[clang-tools-extra] [clang-tidy][NFC] Avoid qualifying names with `llvm::` or `clang::` where possible (PR #185169)

Victor Chernyakin via cfe-commits cfe-commits at lists.llvm.org
Sat Mar 7 01:34:28 PST 2026


https://github.com/localspook created https://github.com/llvm/llvm-project/pull/185169

We have a de-facto policy in clang-tidy to not qualify names unless absolutely necessary. We're *mostly* consistent about following it (especially in new code), but a number of deviations have accumulated over the years too. This makes it jarring to read the code and probably makes it more confusing for newcomers to contribute to the project (do I qualify X or not?). This PR tries to improve the situation by regularizing the codebase.

>From 4af12f50de3e2f35c12145d8c829d330aa0839e3 Mon Sep 17 00:00:00 2001
From: Victor Chernyakin <chernyakin.victor.j at outlook.com>
Date: Sat, 7 Mar 2026 00:42:10 -0800
Subject: [PATCH] [clang-tidy][NFC] Avoid qualifying names with `llvm::` or
 `clang::` where possible

---
 clang-tools-extra/clang-tidy/ClangTidy.cpp    |  36 +-
 clang-tools-extra/clang-tidy/ClangTidy.h      |   9 +-
 .../ClangTidyDiagnosticConsumer.cpp           |  34 +-
 .../clang-tidy/ClangTidyModule.h              |  10 +-
 .../clang-tidy/ClangTidyOptions.cpp           |  19 +-
 .../clang-tidy/ClangTidyOptions.h             |  29 +-
 .../ExpandModularHeadersPPCallbacks.cpp       |  10 +-
 clang-tools-extra/clang-tidy/GlobList.cpp     |   4 +-
 clang-tools-extra/clang-tidy/GlobList.h       |   2 +-
 .../clang-tidy/NoLintDirectiveHandler.h       |   4 +-
 .../abseil/DurationAdditionCheck.cpp          |   8 +-
 .../abseil/DurationConversionCastCheck.cpp    |   6 +-
 .../abseil/DurationFactoryFloatCheck.cpp      |   6 +-
 .../abseil/DurationFactoryScaleCheck.cpp      |  13 +-
 .../clang-tidy/abseil/DurationRewriter.cpp    |  32 +-
 .../clang-tidy/abseil/DurationRewriter.h      |  14 +-
 .../abseil/FasterStrsplitDelimiterCheck.cpp   |   2 +-
 .../abseil/RedundantStrcatCallsCheck.cpp      |  16 +-
 .../abseil/TimeSubtractionCheck.cpp           |   8 +-
 .../clang-tidy/abseil/TimeSubtractionCheck.h  |   2 +-
 .../abseil/UncheckedStatusOrAccessCheck.cpp   |   2 +-
 .../UpgradeDurationConversionsCheck.cpp       |   2 +-
 .../altera/StructPackAlignCheck.cpp           |   4 +-
 .../clang-tidy/boost/UseRangesCheck.cpp       |   2 +-
 .../bugprone/ArgumentCommentCheck.cpp         |   4 +-
 .../bugprone/AssertSideEffectCheck.cpp        |   2 +-
 .../clang-tidy/bugprone/BranchCloneCheck.cpp  |   6 +-
 .../bugprone/ChainedComparisonCheck.cpp       |  10 +-
 ...arePointerToMemberVirtualFunctionCheck.cpp |   2 +-
 .../DerivedMethodShadowingBaseMethodCheck.cpp |   8 +-
 .../DynamicStaticInitializersCheck.cpp        |   2 +-
 .../EasilySwappableParametersCheck.cpp        |   4 +-
 .../clang-tidy/bugprone/EmptyCatchCheck.cpp   |   3 +-
 .../clang-tidy/bugprone/EmptyCatchCheck.h     |   4 +-
 .../bugprone/ExceptionEscapeCheck.cpp         |   2 +-
 .../ForwardingReferenceOverloadCheck.cpp      |   2 +-
 .../IncorrectEnableSharedFromThisCheck.cpp    |   2 +-
 .../bugprone/NarrowingConversionsCheck.cpp    |  12 +-
 .../bugprone/OptionalValueConversionCheck.cpp |   2 +-
 .../bugprone/ParentVirtualCallCheck.cpp       |   5 +-
 .../RawMemoryCallOnNonTrivialTypeCheck.cpp    |   2 +-
 .../bugprone/ReservedIdentifierCheck.cpp      |   4 +-
 .../bugprone/ReservedIdentifierCheck.h        |   4 +-
 .../ReturnConstRefFromParameterCheck.cpp      |   2 +-
 .../bugprone/SignalHandlerCheck.cpp           |   2 +-
 .../clang-tidy/bugprone/SignalHandlerCheck.h  |   7 +-
 .../bugprone/SignedCharMisuseCheck.cpp        |   4 +-
 .../bugprone/SignedCharMisuseCheck.h          |   4 +-
 .../bugprone/SmartPtrArrayMismatchCheck.cpp   |   2 +-
 .../bugprone/StandaloneEmptyCheck.cpp         |  18 +-
 .../StdNamespaceModificationCheck.cpp         |   4 +-
 .../bugprone/StringviewNullptrCheck.cpp       |  10 +-
 .../SuspiciousStringviewDataUsageCheck.h      |   4 +-
 .../bugprone/TaggedUnionMemberCountCheck.cpp  |   4 +-
 .../bugprone/UncheckedOptionalAccessCheck.cpp |   6 +-
 .../UnintendedCharOstreamOutputCheck.cpp      |   2 +-
 .../bugprone/UnsafeFunctionsCheck.cpp         |   2 +-
 .../bugprone/UnsafeToAllowExceptionsCheck.h   |   2 +-
 .../bugprone/UnusedReturnValueCheck.cpp       |   6 +-
 .../clang-tidy/bugprone/UseAfterMoveCheck.cpp |  16 +-
 .../clang-tidy/cert/CERTTidyModule.cpp        | 359 +++++++++---------
 .../clang-tidy/concurrency/MtUnsafeCheck.cpp  |  10 +-
 .../MisleadingCaptureDefaultByValueCheck.cpp  |   2 +-
 .../NoSuspendWithLockCheck.cpp                |   2 +-
 .../PreferMemberInitializerCheck.cpp          |  12 +-
 ...undsAvoidUncheckedContainerAccessCheck.cpp |   2 +-
 ...BoundsAvoidUncheckedContainerAccessCheck.h |   6 +-
 .../SpecialMemberFunctionsCheck.cpp           |  10 +-
 .../SpecialMemberFunctionsCheck.h             |   3 +-
 .../clang-tidy/custom/CustomTidyModule.cpp    |   8 +-
 .../clang-tidy/custom/QueryCheck.cpp          |  16 +-
 .../clang-tidy/custom/QueryCheck.h            |   7 +-
 .../clang-tidy/google/FunctionNamingCheck.cpp |   2 +-
 .../google/GlobalVariableDeclarationCheck.cpp |   5 +-
 .../clang-tidy/google/TodoCommentCheck.cpp    |   3 +-
 .../google/UpgradeGoogletestCaseCheck.cpp     |  25 +-
 .../hicpp/IgnoredRemoveResultCheck.cpp        |   2 +-
 .../llvm/UseNewMLIROpBuilderCheck.cpp         |  12 +-
 .../llvmlibc/CalleeNamespaceCheck.cpp         |   2 +-
 .../llvmlibc/InlineFunctionDeclCheck.cpp      |   3 +-
 .../misc/ConfusableIdentifierCheck.cpp        |   6 +-
 .../misc/ConfusableIdentifierCheck.h          |   5 +-
 .../ConfusableTable/BuildConfusableTable.cpp  |   2 +-
 .../misc/CoroutineHostileRAIICheck.h          |   2 +-
 .../misc/HeaderIncludeCycleCheck.cpp          |   4 +-
 .../clang-tidy/misc/IncludeCleanerCheck.cpp   |  12 +-
 .../clang-tidy/misc/IncludeCleanerCheck.h     |   2 +-
 .../clang-tidy/misc/NewDeleteOverloadsCheck.h |   3 +-
 .../clang-tidy/misc/NoRecursionCheck.cpp      |   3 +-
 .../OverrideWithDifferentVisibilityCheck.h    |   2 +-
 .../misc/RedundantExpressionCheck.cpp         |  12 +-
 .../ThrowByValueCatchByReferenceCheck.cpp     |   4 +-
 .../clang-tidy/misc/UnusedUsingDeclsCheck.cpp |   4 +-
 .../misc/UseAnonymousNamespaceCheck.cpp       |   5 +-
 .../clang-tidy/modernize/AvoidBindCheck.cpp   |   4 +-
 .../modernize/AvoidCArraysCheck.cpp           |  39 +-
 .../modernize/AvoidCStyleCastCheck.cpp        |   4 +-
 .../modernize/ConcatNestedNamespacesCheck.h   |   6 +-
 .../clang-tidy/modernize/LoopConvertCheck.cpp |   4 +-
 .../clang-tidy/modernize/LoopConvertUtils.h   |  91 ++---
 .../clang-tidy/modernize/MakeUniqueCheck.cpp  |   3 +-
 .../MinMaxUseInitializerListCheck.cpp         |  10 +-
 .../clang-tidy/modernize/PassByValueCheck.cpp |   4 +-
 ...ReplaceDisallowCopyAndAssignMacroCheck.cpp |   2 +-
 .../clang-tidy/modernize/ShrinkToFitCheck.cpp |   2 +-
 .../clang-tidy/modernize/UseAutoCheck.cpp     |   8 +-
 .../modernize/UseConstraintsCheck.cpp         |   4 +-
 .../UseDesignatedInitializersCheck.cpp        |   6 +-
 .../clang-tidy/modernize/UseEmplaceCheck.cpp  |   4 +-
 .../UseIntegerSignComparisonCheck.cpp         |  16 +-
 .../modernize/UseNodiscardCheck.cpp           |   7 +-
 .../modernize/UseScopedLockCheck.cpp          |  20 +-
 .../clang-tidy/modernize/UseScopedLockCheck.h |   2 +-
 .../modernize/UseStartsEndsWithCheck.cpp      |   7 +-
 .../modernize/UseStdNumbersCheck.cpp          |  49 ++-
 .../clang-tidy/modernize/UseStdPrintCheck.cpp |   4 +-
 .../modernize/UseStringViewCheck.cpp          |   4 +-
 .../modernize/UseStructuredBindingCheck.cpp   |  23 +-
 .../clang-tidy/modernize/UseUsingCheck.cpp    |  10 +-
 .../clang-tidy/mpi/BufferDerefCheck.cpp       |   2 +-
 .../clang-tidy/objc/AssertEqualsCheck.cpp     |   2 +-
 .../objc/PropertyDeclarationCheck.cpp         |  14 +-
 .../openmp/ExceptionEscapeCheck.cpp           |   2 +-
 .../clang-tidy/performance/AvoidEndlCheck.cpp |   4 +-
 .../performance/InefficientAlgorithmCheck.cpp |   2 +-
 .../InefficientVectorOperationCheck.cpp       |   4 +-
 .../UnnecessaryCopyInitializationCheck.cpp    |   5 +-
 .../UnnecessaryCopyInitializationCheck.h      |   2 +-
 .../UnnecessaryValueParamCheck.cpp            |   2 +-
 .../portability/AvoidPragmaOnceCheck.cpp      |   2 +-
 .../portability/RestrictSystemIncludesCheck.h |   2 +-
 .../portability/SIMDIntrinsicsCheck.h         |   2 +-
 .../readability/ConstReturnTypeCheck.cpp      |   6 +-
 .../readability/ContainerSizeEmptyCheck.cpp   |   9 +-
 .../readability/ContainerSizeEmptyCheck.h     |   2 +-
 .../ConvertMemberFunctionsToStaticCheck.cpp   |   4 +-
 .../readability/ElseAfterReturnCheck.cpp      |  10 +-
 .../readability/EnumInitialValueCheck.cpp     |   2 +-
 .../readability/IdentifierNamingCheck.cpp     |   7 +-
 .../readability/IdentifierNamingCheck.h       |   2 +-
 ...onsistentDeclarationParameterNameCheck.cpp |   6 +-
 .../readability/MagicNumbersCheck.cpp         |   6 +-
 .../readability/MagicNumbersCheck.h           |  28 +-
 .../MakeMemberFunctionConstCheck.cpp          |   4 +-
 .../MathMissingParenthesesCheck.cpp           |  13 +-
 .../readability/NamedParameterCheck.cpp       |   2 +-
 .../readability/NamespaceCommentCheck.h       |   2 +-
 .../OperatorsRepresentationCheck.cpp          |  30 +-
 .../OperatorsRepresentationCheck.h            |   4 +-
 .../readability/QualifiedAutoCheck.cpp        |   6 +-
 .../ReferenceToConstructedTemporaryCheck.cpp  |   6 +-
 .../readability/SimplifyBooleanExprCheck.cpp  |   2 +-
 .../readability/UseStdMinMaxCheck.cpp         |  29 +-
 .../clang-tidy/tool/ClangTidyMain.cpp         |  10 +-
 .../clang-tidy/utils/ASTUtils.cpp             |   4 +-
 .../clang-tidy/utils/DeclRefExprUtils.cpp     |   2 +-
 .../utils/DesignatedInitializers.cpp          |  12 +-
 .../clang-tidy/utils/DesignatedInitializers.h |   4 +-
 .../clang-tidy/utils/ExceptionAnalyzer.cpp    |   4 +-
 .../clang-tidy/utils/ExprSequence.cpp         |   4 +-
 .../clang-tidy/utils/FixItHintUtils.cpp       |  11 +-
 .../utils/FormatStringConverter.cpp           |  29 +-
 .../clang-tidy/utils/FormatStringConverter.h  |   5 +-
 .../clang-tidy/utils/IncludeInserter.cpp      |   2 +-
 .../clang-tidy/utils/IncludeInserter.h        |   5 +-
 .../clang-tidy/utils/Matchers.cpp             |   2 +-
 clang-tools-extra/clang-tidy/utils/Matchers.h |   9 +-
 .../clang-tidy/utils/NamespaceAliaser.h       |   5 +-
 .../utils/RenamerClangTidyCheck.cpp           |   2 +-
 .../clang-tidy/utils/UseRangesCheck.cpp       |   8 +-
 .../clang-tidy/utils/UsingInserter.h          |  10 +-
 171 files changed, 809 insertions(+), 883 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/ClangTidy.cpp b/clang-tools-extra/clang-tidy/ClangTidy.cpp
index 7a898ef07b275..e9340ac703cb5 100644
--- a/clang-tools-extra/clang-tidy/ClangTidy.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidy.cpp
@@ -362,9 +362,8 @@ ClangTidyASTConsumerFactory::ClangTidyASTConsumerFactory(
 }
 
 #if CLANG_TIDY_ENABLE_STATIC_ANALYZER
-static void
-setStaticAnalyzerCheckerOpts(const ClangTidyOptions &Opts,
-                             clang::AnalyzerOptions &AnalyzerOptions) {
+static void setStaticAnalyzerCheckerOpts(const ClangTidyOptions &Opts,
+                                         AnalyzerOptions &AnalyzerOptions) {
   for (const auto &Opt : Opts.CheckOptions) {
     StringRef OptName(Opt.getKey());
     if (!OptName.consume_front(AnalyzerCheckNamePrefix))
@@ -409,9 +408,9 @@ static CheckersList getAnalyzerCheckersAndPackages(ClangTidyContext &Context,
 }
 #endif // CLANG_TIDY_ENABLE_STATIC_ANALYZER
 
-std::unique_ptr<clang::ASTConsumer>
-ClangTidyASTConsumerFactory::createASTConsumer(
-    clang::CompilerInstance &Compiler, StringRef File) {
+std::unique_ptr<ASTConsumer>
+ClangTidyASTConsumerFactory::createASTConsumer(CompilerInstance &Compiler,
+                                               StringRef File) {
   // FIXME: Move this to a separate method, so that CreateASTConsumer doesn't
   // modify Compiler.
   SourceManager *SM = &Compiler.getSourceManager();
@@ -516,10 +515,10 @@ ClangTidyOptions::OptionMap ClangTidyASTConsumerFactory::getCheckOptions() {
 std::vector<std::string> getCheckNames(const ClangTidyOptions &Options,
                                        bool AllowEnablingAnalyzerAlphaCheckers,
                                        bool ExperimentalCustomChecks) {
-  clang::tidy::ClangTidyContext Context(
-      std::make_unique<DefaultOptionsProvider>(ClangTidyGlobalOptions(),
-                                               Options),
-      AllowEnablingAnalyzerAlphaCheckers, false, ExperimentalCustomChecks);
+  ClangTidyContext Context(std::make_unique<DefaultOptionsProvider>(
+                               ClangTidyGlobalOptions(), Options),
+                           AllowEnablingAnalyzerAlphaCheckers, false,
+                           ExperimentalCustomChecks);
   ClangTidyASTConsumerFactory Factory(Context);
   return Factory.getCheckNames();
 }
@@ -542,10 +541,10 @@ ClangTidyOptions::OptionMap
 getCheckOptions(const ClangTidyOptions &Options,
                 bool AllowEnablingAnalyzerAlphaCheckers,
                 bool ExperimentalCustomChecks) {
-  clang::tidy::ClangTidyContext Context(
-      std::make_unique<DefaultOptionsProvider>(ClangTidyGlobalOptions(),
-                                               Options),
-      AllowEnablingAnalyzerAlphaCheckers, false, ExperimentalCustomChecks);
+  ClangTidyContext Context(std::make_unique<DefaultOptionsProvider>(
+                               ClangTidyGlobalOptions(), Options),
+                           AllowEnablingAnalyzerAlphaCheckers, false,
+                           ExperimentalCustomChecks);
   ClangTidyDiagnosticConsumer DiagConsumer(Context);
   auto DiagOpts = std::make_unique<DiagnosticOptions>();
   DiagnosticsEngine DE(llvm::makeIntrusiveRefCnt<DiagnosticIDs>(), *DiagOpts,
@@ -556,12 +555,11 @@ getCheckOptions(const ClangTidyOptions &Options,
 }
 
 std::vector<ClangTidyError>
-runClangTidy(clang::tidy::ClangTidyContext &Context,
-             const CompilationDatabase &Compilations,
+runClangTidy(ClangTidyContext &Context, const CompilationDatabase &Compilations,
              ArrayRef<std::string> InputFiles,
              llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> BaseFS,
              bool ApplyAnyFix, bool EnableCheckProfile,
-             llvm::StringRef StoreCheckProfile, bool Quiet) {
+             StringRef StoreCheckProfile, bool Quiet) {
   ClangTool Tool(Compilations, InputFiles,
                  std::make_shared<PCHContainerOperations>(), BaseFS);
 
@@ -685,7 +683,7 @@ void handleErrors(llvm::ArrayRef<ClangTidyError> Errors,
   WarningsAsErrorsCount += Reporter.getWarningsAsErrorsCount();
 }
 
-void exportReplacements(const llvm::StringRef MainFilePath,
+void exportReplacements(const StringRef MainFilePath,
                         const std::vector<ClangTidyError> &Errors,
                         raw_ostream &OS) {
   TranslationUnitDiagnostics TUD;
@@ -706,7 +704,7 @@ ChecksAndOptions getAllChecksAndOptions(bool AllowEnablingAnalyzerAlphaCheckers,
   ChecksAndOptions Result;
   ClangTidyOptions Opts;
   Opts.Checks = "*";
-  clang::tidy::ClangTidyContext Context(
+  ClangTidyContext Context(
       std::make_unique<DefaultOptionsProvider>(ClangTidyGlobalOptions(), Opts),
       AllowEnablingAnalyzerAlphaCheckers, false, ExperimentalCustomChecks);
   ClangTidyCheckFactories Factories;
diff --git a/clang-tools-extra/clang-tidy/ClangTidy.h b/clang-tools-extra/clang-tidy/ClangTidy.h
index e238f2357caeb..5fac25bd3bbca 100644
--- a/clang-tools-extra/clang-tidy/ClangTidy.h
+++ b/clang-tools-extra/clang-tidy/ClangTidy.h
@@ -38,8 +38,8 @@ class ClangTidyASTConsumerFactory {
       IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFS = nullptr);
 
   /// Returns an ASTConsumer that runs the specified clang-tidy checks.
-  std::unique_ptr<clang::ASTConsumer>
-  createASTConsumer(clang::CompilerInstance &Compiler, StringRef File);
+  std::unique_ptr<ASTConsumer> createASTConsumer(CompilerInstance &Compiler,
+                                                 StringRef File);
 
   /// Get the list of enabled checks.
   std::vector<std::string> getCheckNames();
@@ -91,13 +91,12 @@ void filterCheckOptions(ClangTidyOptions &Options,
 /// the profile will not be output to stderr, but will instead be stored
 /// as a JSON file in the specified directory.
 std::vector<ClangTidyError>
-runClangTidy(clang::tidy::ClangTidyContext &Context,
+runClangTidy(ClangTidyContext &Context,
              const tooling::CompilationDatabase &Compilations,
              ArrayRef<std::string> InputFiles,
              llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> BaseFS,
              bool ApplyAnyFix, bool EnableCheckProfile = false,
-             llvm::StringRef StoreCheckProfile = StringRef(),
-             bool Quiet = false);
+             StringRef StoreCheckProfile = {}, bool Quiet = false);
 
 /// Controls what kind of fixes clang-tidy is allowed to apply.
 enum FixBehaviour {
diff --git a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
index 337d660b1f93b..f7232645a329c 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
@@ -510,57 +510,57 @@ void ClangTidyDiagnosticConsumer::forwardDiagnostic(const Diagnostic &Info) {
   for (unsigned Index = 0; Index < Info.getNumArgs(); ++Index) {
     const DiagnosticsEngine::ArgumentKind Kind = Info.getArgKind(Index);
     switch (Kind) {
-    case clang::DiagnosticsEngine::ak_std_string:
+    case DiagnosticsEngine::ak_std_string:
       Builder << Info.getArgStdStr(Index);
       break;
-    case clang::DiagnosticsEngine::ak_c_string:
+    case DiagnosticsEngine::ak_c_string:
       Builder << Info.getArgCStr(Index);
       break;
-    case clang::DiagnosticsEngine::ak_sint:
+    case DiagnosticsEngine::ak_sint:
       Builder << Info.getArgSInt(Index);
       break;
-    case clang::DiagnosticsEngine::ak_uint:
+    case DiagnosticsEngine::ak_uint:
       Builder << Info.getArgUInt(Index);
       break;
-    case clang::DiagnosticsEngine::ak_tokenkind:
+    case DiagnosticsEngine::ak_tokenkind:
       Builder << static_cast<tok::TokenKind>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_identifierinfo:
+    case DiagnosticsEngine::ak_identifierinfo:
       Builder << Info.getArgIdentifier(Index);
       break;
-    case clang::DiagnosticsEngine::ak_qual:
+    case DiagnosticsEngine::ak_qual:
       Builder << Qualifiers::fromOpaqueValue(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_qualtype:
+    case DiagnosticsEngine::ak_qualtype:
       Builder << QualType::getFromOpaquePtr(
           reinterpret_cast<void *>(Info.getRawArg(Index)));
       break;
-    case clang::DiagnosticsEngine::ak_declarationname:
+    case DiagnosticsEngine::ak_declarationname:
       Builder << DeclarationName::getFromOpaqueInteger(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_nameddecl:
+    case DiagnosticsEngine::ak_nameddecl:
       Builder << reinterpret_cast<const NamedDecl *>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_nestednamespec:
+    case DiagnosticsEngine::ak_nestednamespec:
       Builder << NestedNameSpecifier::getFromVoidPointer(
           reinterpret_cast<void *>(Info.getRawArg(Index)));
       break;
-    case clang::DiagnosticsEngine::ak_declcontext:
+    case DiagnosticsEngine::ak_declcontext:
       Builder << reinterpret_cast<DeclContext *>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_qualtype_pair:
+    case DiagnosticsEngine::ak_qualtype_pair:
       assert(false); // This one is not passed around.
       break;
-    case clang::DiagnosticsEngine::ak_attr:
+    case DiagnosticsEngine::ak_attr:
       Builder << reinterpret_cast<Attr *>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_attr_info:
+    case DiagnosticsEngine::ak_attr_info:
       Builder << reinterpret_cast<AttributeCommonInfo *>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_addrspace:
+    case DiagnosticsEngine::ak_addrspace:
       Builder << static_cast<LangAS>(Info.getRawArg(Index));
       break;
-    case clang::DiagnosticsEngine::ak_expr:
+    case DiagnosticsEngine::ak_expr:
       Builder << reinterpret_cast<const Expr *>(Info.getRawArg(Index));
     }
   }
diff --git a/clang-tools-extra/clang-tidy/ClangTidyModule.h b/clang-tools-extra/clang-tidy/ClangTidyModule.h
index c2d623540999b..3db92c2dab981 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyModule.h
+++ b/clang-tools-extra/clang-tidy/ClangTidyModule.h
@@ -28,12 +28,12 @@ class ClangTidyContext;
 class ClangTidyCheckFactories {
 public:
   using CheckFactory = std::function<std::unique_ptr<ClangTidyCheck>(
-      llvm::StringRef Name, ClangTidyContext *Context)>;
+      StringRef Name, ClangTidyContext *Context)>;
 
   /// Registers check \p Factory with name \p Name.
   ///
   /// For all checks that have default constructors, use \c registerCheck.
-  void registerCheckFactory(llvm::StringRef Name, CheckFactory Factory);
+  void registerCheckFactory(StringRef Name, CheckFactory Factory);
 
   /// Registers the \c CheckType with the name \p Name.
   ///
@@ -56,14 +56,14 @@ class ClangTidyCheckFactories {
   ///   }
   /// };
   /// \endcode
-  template <typename CheckType> void registerCheck(llvm::StringRef CheckName) {
+  template <typename CheckType> void registerCheck(StringRef CheckName) {
     registerCheckFactory(CheckName,
-                         [](llvm::StringRef Name, ClangTidyContext *Context) {
+                         [](StringRef Name, ClangTidyContext *Context) {
                            return std::make_unique<CheckType>(Name, Context);
                          });
   }
 
-  void eraseCheck(llvm::StringRef CheckName) { Factories.erase(CheckName); }
+  void eraseCheck(StringRef CheckName) { Factories.erase(CheckName); }
 
   /// Create instances of checks that are enabled.
   std::vector<std::unique_ptr<ClangTidyCheck>>
diff --git a/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp b/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
index 317fbd9173af7..0a0f392346f6d 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
@@ -324,8 +324,7 @@ ClangTidyOptions ClangTidyOptions::merge(const ClangTidyOptions &Other,
   return Result;
 }
 
-ClangTidyOptions
-ClangTidyOptionsProvider::getOptions(llvm::StringRef FileName) {
+ClangTidyOptions ClangTidyOptionsProvider::getOptions(StringRef FileName) {
   ClangTidyOptions Result;
   unsigned Priority = 0;
   for (auto &Source : getRawOptions(FileName))
@@ -334,7 +333,7 @@ ClangTidyOptionsProvider::getOptions(llvm::StringRef FileName) {
 }
 
 std::vector<OptionsSource>
-DefaultOptionsProvider::getRawOptions(llvm::StringRef FileName) {
+DefaultOptionsProvider::getRawOptions(StringRef FileName) {
   std::vector<OptionsSource> Result;
   Result.emplace_back(DefaultOptions, OptionsSourceTypeDefaultBinary);
   return Result;
@@ -350,14 +349,14 @@ ConfigOptionsProvider::ConfigOptionsProvider(
       ConfigOptions(std::move(ConfigOptions)) {}
 
 std::vector<OptionsSource>
-ConfigOptionsProvider::getRawOptions(llvm::StringRef FileName) {
+ConfigOptionsProvider::getRawOptions(StringRef FileName) {
   std::vector<OptionsSource> RawOptions =
       DefaultOptionsProvider::getRawOptions(FileName);
   if (ConfigOptions.InheritParentConfig.value_or(false)) {
     LLVM_DEBUG(llvm::dbgs()
                << "Getting options for file " << FileName << "...\n");
 
-    llvm::ErrorOr<llvm::SmallString<128>> AbsoluteFilePath =
+    llvm::ErrorOr<SmallString<128>> AbsoluteFilePath =
         getNormalizedAbsolutePath(FileName);
     if (AbsoluteFilePath)
       addRawFileOptions(AbsoluteFilePath->str(), RawOptions);
@@ -390,10 +389,10 @@ FileOptionsBaseProvider::FileOptionsBaseProvider(
       OverrideOptions(std::move(OverrideOptions)),
       ConfigHandlers(std::move(ConfigHandlers)) {}
 
-llvm::ErrorOr<llvm::SmallString<128>>
-FileOptionsBaseProvider::getNormalizedAbsolutePath(llvm::StringRef Path) {
+llvm::ErrorOr<SmallString<128>>
+FileOptionsBaseProvider::getNormalizedAbsolutePath(StringRef Path) {
   assert(FS && "FS must be set.");
-  llvm::SmallString<128> NormalizedAbsolutePath = {Path};
+  SmallString<128> NormalizedAbsolutePath = {Path};
   const std::error_code Err = FS->makeAbsolute(NormalizedAbsolutePath);
   if (Err)
     return Err;
@@ -402,7 +401,7 @@ FileOptionsBaseProvider::getNormalizedAbsolutePath(llvm::StringRef Path) {
 }
 
 void FileOptionsBaseProvider::addRawFileOptions(
-    llvm::StringRef AbsolutePath, std::vector<OptionsSource> &CurOptions) {
+    StringRef AbsolutePath, std::vector<OptionsSource> &CurOptions) {
   auto CurSize = CurOptions.size();
   // Look for a suitable configuration file in all parent directories of the
   // file. Start with the immediate parent directory and move up.
@@ -465,7 +464,7 @@ FileOptionsProvider::getRawOptions(StringRef FileName) {
   LLVM_DEBUG(llvm::dbgs() << "Getting options for file " << FileName
                           << "...\n");
 
-  const llvm::ErrorOr<llvm::SmallString<128>> AbsoluteFilePath =
+  const llvm::ErrorOr<SmallString<128>> AbsoluteFilePath =
       getNormalizedAbsolutePath(FileName);
   if (!AbsoluteFilePath)
     return {};
diff --git a/clang-tools-extra/clang-tidy/ClangTidyOptions.h b/clang-tools-extra/clang-tidy/ClangTidyOptions.h
index 23bbfb01c2ecd..73fdbabd5bdba 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyOptions.h
+++ b/clang-tools-extra/clang-tidy/ClangTidyOptions.h
@@ -116,7 +116,7 @@ struct ClangTidyOptions {
   struct ClangTidyValue {
     ClangTidyValue() = default;
     ClangTidyValue(const char *Value) : Value(Value) {}
-    ClangTidyValue(llvm::StringRef Value, unsigned Priority = 0)
+    ClangTidyValue(StringRef Value, unsigned Priority = 0)
         : Value(Value), Priority(Priority) {}
 
     std::string Value;
@@ -138,9 +138,9 @@ struct ClangTidyOptions {
   struct CustomCheckValue {
     std::string Name;
     std::string Query;
-    llvm::SmallVector<CustomCheckDiag> Diags;
+    SmallVector<CustomCheckDiag> Diags;
   };
-  using CustomCheckValueList = llvm::SmallVector<CustomCheckValue>;
+  using CustomCheckValueList = SmallVector<CustomCheckValue>;
   std::optional<CustomCheckValueList> CustomChecks;
 
   using ArgList = std::vector<std::string>;
@@ -193,12 +193,11 @@ class ClangTidyOptionsProvider {
 
   /// Returns an ordered vector of OptionsSources, in order of increasing
   /// priority.
-  virtual std::vector<OptionsSource>
-  getRawOptions(llvm::StringRef FileName) = 0;
+  virtual std::vector<OptionsSource> getRawOptions(StringRef FileName) = 0;
 
   /// Returns options applying to a specific translation unit with the
   /// specified \p FileName.
-  ClangTidyOptions getOptions(llvm::StringRef FileName);
+  ClangTidyOptions getOptions(StringRef FileName);
 };
 
 /// Implementation of the \c ClangTidyOptionsProvider interface, which
@@ -212,7 +211,7 @@ class DefaultOptionsProvider : public ClangTidyOptionsProvider {
   const ClangTidyGlobalOptions &getGlobalOptions() override {
     return GlobalOptions;
   }
-  std::vector<OptionsSource> getRawOptions(llvm::StringRef FileName) override;
+  std::vector<OptionsSource> getRawOptions(StringRef FileName) override;
 
 private:
   ClangTidyGlobalOptions GlobalOptions;
@@ -256,19 +255,19 @@ class FileOptionsBaseProvider : public DefaultOptionsProvider {
                           ClangTidyOptions OverrideOptions,
                           ConfigFileHandlers ConfigHandlers);
 
-  void addRawFileOptions(llvm::StringRef AbsolutePath,
+  void addRawFileOptions(StringRef AbsolutePath,
                          std::vector<OptionsSource> &CurOptions);
 
-  llvm::ErrorOr<llvm::SmallString<128>>
-  getNormalizedAbsolutePath(llvm::StringRef AbsolutePath);
+  llvm::ErrorOr<SmallString<128>>
+  getNormalizedAbsolutePath(StringRef AbsolutePath);
 
   /// Try to read configuration files from \p Directory using registered
   /// \c ConfigHandlers.
-  std::optional<OptionsSource> tryReadConfigFile(llvm::StringRef Directory);
+  std::optional<OptionsSource> tryReadConfigFile(StringRef Directory);
 
   struct OptionsCache {
     llvm::StringMap<size_t> Memorized;
-    llvm::SmallVector<OptionsSource, 4U> Storage;
+    SmallVector<OptionsSource, 4U> Storage;
   } CachedOptions;
   ClangTidyOptions OverrideOptions;
   ConfigFileHandlers ConfigHandlers;
@@ -283,7 +282,7 @@ class ConfigOptionsProvider : public FileOptionsBaseProvider {
       ClangTidyGlobalOptions GlobalOptions, ClangTidyOptions DefaultOptions,
       ClangTidyOptions ConfigOptions, ClangTidyOptions OverrideOptions,
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
-  std::vector<OptionsSource> getRawOptions(llvm::StringRef FileName) override;
+  std::vector<OptionsSource> getRawOptions(StringRef FileName) override;
 
 private:
   ClangTidyOptions ConfigOptions;
@@ -336,11 +335,11 @@ class FileOptionsProvider : public FileOptionsBaseProvider {
                       ClangTidyOptions OverrideOptions,
                       ConfigFileHandlers ConfigHandlers);
 
-  std::vector<OptionsSource> getRawOptions(llvm::StringRef FileName) override;
+  std::vector<OptionsSource> getRawOptions(StringRef FileName) override;
 };
 
 /// Parses LineFilter from JSON and stores it to the \p Options.
-std::error_code parseLineFilter(llvm::StringRef LineFilter,
+std::error_code parseLineFilter(StringRef LineFilter,
                                 ClangTidyGlobalOptions &Options);
 
 /// Parses configuration from JSON and returns \c ClangTidyOptions or an
diff --git a/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp b/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
index 8a865f1352599..cb6de9962956d 100644
--- a/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
+++ b/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
@@ -88,11 +88,11 @@ ExpandModularHeadersPPCallbacks::ExpandModularHeadersPPCallbacks(
   HeaderInfo = std::make_unique<HeaderSearch>(HSOpts, Sources, Diags, LangOpts,
                                               &Compiler.getTarget());
 
-  PP = std::make_unique<clang::Preprocessor>(Compiler.getPreprocessorOpts(),
-                                             Diags, LangOpts, Sources,
-                                             *HeaderInfo, ModuleLoader,
-                                             /*IILookup=*/nullptr,
-                                             /*OwnsHeaderSearch=*/false);
+  PP = std::make_unique<Preprocessor>(Compiler.getPreprocessorOpts(), Diags,
+                                      LangOpts, Sources, *HeaderInfo,
+                                      ModuleLoader,
+                                      /*IILookup=*/nullptr,
+                                      /*OwnsHeaderSearch=*/false);
   PP->Initialize(Compiler.getTarget(), Compiler.getAuxTarget());
   InitializePreprocessor(*PP, Compiler.getPreprocessorOpts(),
                          Compiler.getPCHContainerReader(),
diff --git a/clang-tools-extra/clang-tidy/GlobList.cpp b/clang-tools-extra/clang-tidy/GlobList.cpp
index 7c72af9d06b12..442322f68fdb3 100644
--- a/clang-tools-extra/clang-tidy/GlobList.cpp
+++ b/clang-tools-extra/clang-tidy/GlobList.cpp
@@ -22,7 +22,7 @@ static bool consumeNegativeIndicator(StringRef &GlobList) {
 // Extracts the first glob from the comma-separated list of globs,
 // removes it and the trailing comma from the GlobList and
 // returns the extracted glob.
-static llvm::StringRef extractNextGlob(StringRef &GlobList) {
+static StringRef extractNextGlob(StringRef &GlobList) {
   const StringRef UntrimmedGlob =
       GlobList.substr(0, GlobList.find_first_of(",\n"));
   const StringRef Glob = UntrimmedGlob.trim();
@@ -31,7 +31,7 @@ static llvm::StringRef extractNextGlob(StringRef &GlobList) {
 }
 
 static llvm::Regex createRegexFromGlob(StringRef &Glob) {
-  llvm::SmallString<128> RegexText("^");
+  SmallString<128> RegexText("^");
   const StringRef MetaChars("()^$|*+?.[]\\{}");
   for (const char C : Glob) {
     if (C == '*')
diff --git a/clang-tools-extra/clang-tidy/GlobList.h b/clang-tools-extra/clang-tidy/GlobList.h
index 9567abf6b1d10..a48ef0132fc6c 100644
--- a/clang-tools-extra/clang-tidy/GlobList.h
+++ b/clang-tools-extra/clang-tidy/GlobList.h
@@ -44,7 +44,7 @@ class GlobList {
   struct GlobListItem {
     bool IsPositive;
     llvm::Regex Regex;
-    llvm::StringRef Text;
+    StringRef Text;
   };
   SmallVector<GlobListItem, 0> Items;
 
diff --git a/clang-tools-extra/clang-tidy/NoLintDirectiveHandler.h b/clang-tools-extra/clang-tidy/NoLintDirectiveHandler.h
index e33d0f2781886..4aafd34b33956 100644
--- a/clang-tools-extra/clang-tidy/NoLintDirectiveHandler.h
+++ b/clang-tools-extra/clang-tidy/NoLintDirectiveHandler.h
@@ -33,8 +33,8 @@ class NoLintDirectiveHandler {
   ~NoLintDirectiveHandler();
 
   bool shouldSuppress(DiagnosticsEngine::Level DiagLevel,
-                      const Diagnostic &Diag, llvm::StringRef DiagName,
-                      llvm::SmallVectorImpl<tooling::Diagnostic> &NoLintErrors,
+                      const Diagnostic &Diag, StringRef DiagName,
+                      SmallVectorImpl<tooling::Diagnostic> &NoLintErrors,
                       bool AllowIO, bool EnableNoLintBlocks);
 
 private:
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationAdditionCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationAdditionCheck.cpp
index 421e5973d4fe0..60d0ac0b0fb66 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationAdditionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationAdditionCheck.cpp
@@ -29,19 +29,19 @@ void DurationAdditionCheck::registerMatchers(MatchFinder *Finder) {
 }
 
 void DurationAdditionCheck::check(const MatchFinder::MatchResult &Result) {
-  const auto *Binop = Result.Nodes.getNodeAs<clang::BinaryOperator>("binop");
-  const auto *Call = Result.Nodes.getNodeAs<clang::CallExpr>("call");
+  const auto *Binop = Result.Nodes.getNodeAs<BinaryOperator>("binop");
+  const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
 
   // Don't try to replace things inside of macro definitions.
   if (Binop->getExprLoc().isMacroID() || Binop->getExprLoc().isInvalid())
     return;
 
   std::optional<DurationScale> Scale = getScaleForTimeInverse(
-      Result.Nodes.getNodeAs<clang::FunctionDecl>("function_decl")->getName());
+      Result.Nodes.getNodeAs<FunctionDecl>("function_decl")->getName());
   if (!Scale)
     return;
 
-  const llvm::StringRef TimeFactory = getTimeInverseForScale(*Scale);
+  const StringRef TimeFactory = getTimeInverseForScale(*Scale);
 
   FixItHint Hint;
   if (Call == Binop->getLHS()->IgnoreParenImpCasts()) {
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationConversionCastCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationConversionCastCheck.cpp
index ef06a9e2ba572..ae2cf5b4cb642 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationConversionCastCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationConversionCastCheck.cpp
@@ -51,8 +51,7 @@ void DurationConversionCastCheck::check(
   // Casting a double to an integer.
   if (MatchedCast->getTypeAsWritten()->isIntegerType() &&
       ConversionFuncName.contains("Double")) {
-    const llvm::StringRef NewFuncName =
-        getDurationInverseForScale(*Scale).second;
+    const StringRef NewFuncName = getDurationInverseForScale(*Scale).second;
 
     diag(MatchedCast->getBeginLoc(),
          "duration should be converted directly to an integer rather than "
@@ -67,8 +66,7 @@ void DurationConversionCastCheck::check(
   // Casting an integer to a double.
   if (MatchedCast->getTypeAsWritten()->isRealFloatingType() &&
       ConversionFuncName.contains("Int64")) {
-    const llvm::StringRef NewFuncName =
-        getDurationInverseForScale(*Scale).first;
+    const StringRef NewFuncName = getDurationInverseForScale(*Scale).first;
 
     diag(MatchedCast->getBeginLoc(), "duration should be converted directly to "
                                      "a floating-point number rather than "
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
index 83906fe05054f..6528d4ed306b3 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
@@ -20,9 +20,9 @@ namespace clang::tidy::abseil {
 // Returns `true` if `Range` is inside a macro definition.
 static bool insideMacroDefinition(const MatchFinder::MatchResult &Result,
                                   SourceRange Range) {
-  return !clang::Lexer::makeFileCharRange(
-              clang::CharSourceRange::getCharRange(Range),
-              *Result.SourceManager, Result.Context->getLangOpts())
+  return !Lexer::makeFileCharRange(CharSourceRange::getCharRange(Range),
+                                   *Result.SourceManager,
+                                   Result.Context->getLangOpts())
               .isValid();
 }
 
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationFactoryScaleCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationFactoryScaleCheck.cpp
index b29fd3a0b94ee..4f1a288d219ec 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationFactoryScaleCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationFactoryScaleCheck.cpp
@@ -20,8 +20,7 @@ namespace clang::tidy::abseil {
 // Given the name of a duration factory function, return the appropriate
 // `DurationScale` for that factory.  If no factory can be found for
 // `FactoryName`, return `std::nullopt`.
-static std::optional<DurationScale>
-getScaleForFactory(llvm::StringRef FactoryName) {
+static std::optional<DurationScale> getScaleForFactory(StringRef FactoryName) {
   return llvm::StringSwitch<std::optional<DurationScale>>(FactoryName)
       .Case("Nanoseconds", DurationScale::Nanoseconds)
       .Case("Microseconds", DurationScale::Microseconds)
@@ -169,8 +168,8 @@ void DurationFactoryScaleCheck::check(const MatchFinder::MatchResult &Result) {
     // cases where a user is multiplying by something such as 1e-3.
 
     // First check the LHS
-    const auto *IntLit = llvm::dyn_cast<IntegerLiteral>(MultBinOp->getLHS());
-    const auto *FloatLit = llvm::dyn_cast<FloatingLiteral>(MultBinOp->getLHS());
+    const auto *IntLit = dyn_cast<IntegerLiteral>(MultBinOp->getLHS());
+    const auto *FloatLit = dyn_cast<FloatingLiteral>(MultBinOp->getLHS());
     if (IntLit || FloatLit) {
       NewScale = getNewScale(Scale, getValue(IntLit, FloatLit));
       if (NewScale)
@@ -179,8 +178,8 @@ void DurationFactoryScaleCheck::check(const MatchFinder::MatchResult &Result) {
 
     // If we weren't able to scale based on the LHS, check the RHS
     if (!NewScale) {
-      IntLit = llvm::dyn_cast<IntegerLiteral>(MultBinOp->getRHS());
-      FloatLit = llvm::dyn_cast<FloatingLiteral>(MultBinOp->getRHS());
+      IntLit = dyn_cast<IntegerLiteral>(MultBinOp->getRHS());
+      FloatLit = dyn_cast<FloatingLiteral>(MultBinOp->getRHS());
       if (IntLit || FloatLit) {
         NewScale = getNewScale(Scale, getValue(IntLit, FloatLit));
         if (NewScale)
@@ -191,7 +190,7 @@ void DurationFactoryScaleCheck::check(const MatchFinder::MatchResult &Result) {
                  Result.Nodes.getNodeAs<BinaryOperator>("div_binop")) {
     // We next handle division.
     // For division, we only check the RHS.
-    const auto *FloatLit = llvm::cast<FloatingLiteral>(DivBinOp->getRHS());
+    const auto *FloatLit = cast<FloatingLiteral>(DivBinOp->getRHS());
 
     std::optional<DurationScale> NewScale =
         getNewScale(Scale, 1.0 / FloatLit->getValueAsApproximateDouble());
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationRewriter.cpp b/clang-tools-extra/clang-tidy/abseil/DurationRewriter.cpp
index a78d07d2e5861..035e7d642c8b7 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationRewriter.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/DurationRewriter.cpp
@@ -30,10 +30,10 @@ truncateIfIntegral(const FloatingLiteral &FloatLiteral) {
   return std::nullopt;
 }
 
-const std::pair<llvm::StringRef, llvm::StringRef> &
+const std::pair<StringRef, StringRef> &
 getDurationInverseForScale(DurationScale Scale) {
-  static constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 6>
-      InverseMap = {{
+  static constexpr std::array<std::pair<StringRef, StringRef>, 6> InverseMap = {
+      {
           {"::absl::ToDoubleHours", "::absl::ToInt64Hours"},
           {"::absl::ToDoubleMinutes", "::absl::ToInt64Minutes"},
           {"::absl::ToDoubleSeconds", "::absl::ToInt64Seconds"},
@@ -50,7 +50,7 @@ getDurationInverseForScale(DurationScale Scale) {
 static std::optional<std::string>
 rewriteInverseDurationCall(const MatchFinder::MatchResult &Result,
                            DurationScale Scale, const Expr &Node) {
-  const std::pair<llvm::StringRef, llvm::StringRef> &InverseFunctions =
+  const std::pair<StringRef, StringRef> &InverseFunctions =
       getDurationInverseForScale(Scale);
   if (const auto *MaybeCallArg = selectFirst<const Expr>(
           "e",
@@ -69,7 +69,7 @@ rewriteInverseDurationCall(const MatchFinder::MatchResult &Result,
 static std::optional<std::string>
 rewriteInverseTimeCall(const MatchFinder::MatchResult &Result,
                        DurationScale Scale, const Expr &Node) {
-  const llvm::StringRef InverseFunction = getTimeInverseForScale(Scale);
+  const StringRef InverseFunction = getTimeInverseForScale(Scale);
   if (const auto *MaybeCallArg = selectFirst<const Expr>(
           "e", match(callExpr(callee(functionDecl(hasName(InverseFunction))),
                               hasArgument(0, expr().bind("e"))),
@@ -81,8 +81,8 @@ rewriteInverseTimeCall(const MatchFinder::MatchResult &Result,
 }
 
 /// Returns the factory function name for a given `Scale`.
-llvm::StringRef getDurationFactoryForScale(DurationScale Scale) {
-  static constexpr std::array<llvm::StringRef, 6> FactoryMap = {
+StringRef getDurationFactoryForScale(DurationScale Scale) {
+  static constexpr std::array<StringRef, 6> FactoryMap = {
       "absl::Hours",        "absl::Minutes",      "absl::Seconds",
       "absl::Milliseconds", "absl::Microseconds", "absl::Nanoseconds",
   };
@@ -90,8 +90,8 @@ llvm::StringRef getDurationFactoryForScale(DurationScale Scale) {
   return FactoryMap[llvm::to_underlying(Scale)];
 }
 
-llvm::StringRef getTimeFactoryForScale(DurationScale Scale) {
-  static constexpr std::array<llvm::StringRef, 6> FactoryMap = {
+StringRef getTimeFactoryForScale(DurationScale Scale) {
+  static constexpr std::array<StringRef, 6> FactoryMap = {
       "absl::FromUnixHours",  "absl::FromUnixMinutes", "absl::FromUnixSeconds",
       "absl::FromUnixMillis", "absl::FromUnixMicros",  "absl::FromUnixNanos",
   };
@@ -100,8 +100,8 @@ llvm::StringRef getTimeFactoryForScale(DurationScale Scale) {
 }
 
 /// Returns the Time factory function name for a given `Scale`.
-llvm::StringRef getTimeInverseForScale(DurationScale Scale) {
-  static constexpr std::array<llvm::StringRef, 6> InverseMap = {
+StringRef getTimeInverseForScale(DurationScale Scale) {
+  static constexpr std::array<StringRef, 6> InverseMap = {
       "absl::ToUnixHours",  "absl::ToUnixMinutes", "absl::ToUnixSeconds",
       "absl::ToUnixMillis", "absl::ToUnixMicros",  "absl::ToUnixNanos",
   };
@@ -115,14 +115,14 @@ bool isLiteralZero(const MatchFinder::MatchResult &Result, const Expr &Node) {
       anyOf(integerLiteral(equals(0)), floatLiteral(equals(0.0)));
 
   // Check to see if we're using a zero directly.
-  if (selectFirst<const clang::Expr>(
+  if (selectFirst<const Expr>(
           "val", match(expr(ignoringImpCasts(ZeroMatcher)).bind("val"), Node,
                        *Result.Context)) != nullptr)
     return true;
 
   // Now check to see if we're using a functional cast with a scalar
   // initializer expression, e.g. `int{0}`.
-  if (selectFirst<const clang::Expr>(
+  if (selectFirst<const Expr>(
           "val", match(cxxFunctionalCastExpr(
                            hasDestinationType(
                                anyOf(isInteger(), realFloatingPointType())),
@@ -158,7 +158,7 @@ stripFloatCast(const ast_matchers::MatchFinder::MatchResult &Result,
 std::optional<std::string>
 stripFloatLiteralFraction(const MatchFinder::MatchResult &Result,
                           const Expr &Node) {
-  if (const auto *LitFloat = llvm::dyn_cast<FloatingLiteral>(&Node))
+  if (const auto *LitFloat = dyn_cast<FloatingLiteral>(&Node))
     // Attempt to simplify a `Duration` factory call with a literal argument.
     if (std::optional<llvm::APSInt> IntValue = truncateIfIntegral(*LitFloat))
       return toString(*IntValue, /*radix=*/10);
@@ -181,7 +181,7 @@ std::string simplifyDurationFactoryArg(const MatchFinder::MatchResult &Result,
   return tooling::fixit::getText(Node, *Result.Context).str();
 }
 
-std::optional<DurationScale> getScaleForDurationInverse(llvm::StringRef Name) {
+std::optional<DurationScale> getScaleForDurationInverse(StringRef Name) {
   static const llvm::StringMap<DurationScale> ScaleMap(
       {{"ToDoubleHours", DurationScale::Hours},
        {"ToInt64Hours", DurationScale::Hours},
@@ -203,7 +203,7 @@ std::optional<DurationScale> getScaleForDurationInverse(llvm::StringRef Name) {
   return ScaleIter->second;
 }
 
-std::optional<DurationScale> getScaleForTimeInverse(llvm::StringRef Name) {
+std::optional<DurationScale> getScaleForTimeInverse(StringRef Name) {
   static const llvm::StringMap<DurationScale> ScaleMap(
       {{"ToUnixHours", DurationScale::Hours},
        {"ToUnixMinutes", DurationScale::Minutes},
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationRewriter.h b/clang-tools-extra/clang-tidy/abseil/DurationRewriter.h
index e3b1753e95a16..f9e42a752c185 100644
--- a/clang-tools-extra/clang-tidy/abseil/DurationRewriter.h
+++ b/clang-tools-extra/clang-tidy/abseil/DurationRewriter.h
@@ -11,7 +11,7 @@
 
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
-#include <cinttypes>
+#include <cstdint>
 #include <optional>
 
 namespace clang::tidy::abseil {
@@ -28,11 +28,11 @@ enum class DurationScale : std::uint8_t {
 
 /// Given a `Scale`, return the appropriate factory function call for
 /// constructing a `Duration` for that scale.
-llvm::StringRef getDurationFactoryForScale(DurationScale Scale);
+StringRef getDurationFactoryForScale(DurationScale Scale);
 
 /// Given a 'Scale', return the appropriate factory function call for
 /// constructing a `Time` for that scale.
-llvm::StringRef getTimeFactoryForScale(DurationScale Scale);
+StringRef getTimeFactoryForScale(DurationScale Scale);
 
 // Determine if `Node` represents a literal floating point or integral zero.
 bool isLiteralZero(const ast_matchers::MatchFinder::MatchResult &Result,
@@ -63,20 +63,20 @@ simplifyDurationFactoryArg(const ast_matchers::MatchFinder::MatchResult &Result,
 
 /// Given the name of an inverse Duration function (e.g., `ToDoubleSeconds`),
 /// return its `DurationScale`, or `std::nullopt` if a match is not found.
-std::optional<DurationScale> getScaleForDurationInverse(llvm::StringRef Name);
+std::optional<DurationScale> getScaleForDurationInverse(StringRef Name);
 
 /// Given the name of an inverse Time function (e.g., `ToUnixSeconds`),
 /// return its `DurationScale`, or `std::nullopt` if a match is not found.
-std::optional<DurationScale> getScaleForTimeInverse(llvm::StringRef Name);
+std::optional<DurationScale> getScaleForTimeInverse(StringRef Name);
 
 /// Given a `Scale` return the fully qualified inverse functions for it.
 /// The first returned value is the inverse for `double`, and the second
 /// returned value is the inverse for `int64`.
-const std::pair<llvm::StringRef, llvm::StringRef> &
+const std::pair<StringRef, StringRef> &
 getDurationInverseForScale(DurationScale Scale);
 
 /// Returns the Time inverse function name for a given `Scale`.
-llvm::StringRef getTimeInverseForScale(DurationScale Scale);
+StringRef getTimeInverseForScale(DurationScale Scale);
 
 /// Assuming `Node` has type `double` or `int` representing a time interval of
 /// `Scale`, return the expression to make it a suitable `Duration`.
diff --git a/clang-tools-extra/clang-tidy/abseil/FasterStrsplitDelimiterCheck.cpp b/clang-tools-extra/clang-tidy/abseil/FasterStrsplitDelimiterCheck.cpp
index 0827526ba3b5d..391777225f739 100644
--- a/clang-tools-extra/clang-tidy/abseil/FasterStrsplitDelimiterCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/FasterStrsplitDelimiterCheck.cpp
@@ -28,7 +28,7 @@ makeCharacterLiteral(const StringLiteral *Literal, const ASTContext &Context) {
          "Only single character string should be matched");
   assert(Literal->getCharByteWidth() == 1 &&
          "StrSplit doesn't support wide char");
-  std::string Result = clang::tooling::fixit::getText(*Literal, Context).str();
+  std::string Result = tooling::fixit::getText(*Literal, Context).str();
   const bool IsRawStringLiteral = StringRef(Result).starts_with(R"(R")");
   // Since raw string literal might contain unescaped non-printable characters,
   // we normalize them using `StringLiteral::outputString`.
diff --git a/clang-tools-extra/clang-tidy/abseil/RedundantStrcatCallsCheck.cpp b/clang-tools-extra/clang-tidy/abseil/RedundantStrcatCallsCheck.cpp
index a58c0410c4e35..79d16c7034cef 100644
--- a/clang-tools-extra/clang-tidy/abseil/RedundantStrcatCallsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/RedundantStrcatCallsCheck.cpp
@@ -61,9 +61,9 @@ static void removeCallLeaveArgs(const CallExpr *Call,
           Call->getRParenLoc(), Call->getEndLoc().getLocWithOffset(1))));
 }
 
-static const clang::CallExpr *
-processArgument(const Expr *Arg, const MatchFinder::MatchResult &Result,
-                StrCatCheckResult *CheckResult) {
+static const CallExpr *processArgument(const Expr *Arg,
+                                       const MatchFinder::MatchResult &Result,
+                                       StrCatCheckResult *CheckResult) {
   const auto IsAlphanum = hasDeclaration(cxxMethodDecl(hasName("AlphaNum")));
   static const auto *const Strcat = new auto(hasName("::absl::StrCat"));
   const auto IsStrcat = cxxBindTemporaryExpr(
@@ -89,17 +89,15 @@ static StrCatCheckResult processCall(const CallExpr *RootCall, bool IsAppend,
   while (!CallsToProcess.empty()) {
     ++CheckResult.NumCalls;
 
-    const CallExpr *CallExpr = CallsToProcess.front();
+    const CallExpr *Call = CallsToProcess.front();
     CallsToProcess.pop_front();
 
-    int StartArg = CallExpr == RootCall && IsAppend;
-    for (const auto *Arg : CallExpr->arguments()) {
+    int StartArg = Call == RootCall && IsAppend;
+    for (const auto *Arg : Call->arguments()) {
       if (StartArg-- > 0)
         continue;
-      if (const clang::CallExpr *Sub =
-              processArgument(Arg, Result, &CheckResult)) {
+      if (const CallExpr *Sub = processArgument(Arg, Result, &CheckResult))
         CallsToProcess.push_back(Sub);
-      }
     }
   }
   return CheckResult;
diff --git a/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.cpp b/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.cpp
index 4ae49d285930d..b7d5cf69fdf68 100644
--- a/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.cpp
@@ -20,9 +20,9 @@ namespace clang::tidy::abseil {
 // Returns `true` if `Range` is inside a macro definition.
 static bool insideMacroDefinition(const MatchFinder::MatchResult &Result,
                                   SourceRange Range) {
-  return !clang::Lexer::makeFileCharRange(
-              clang::CharSourceRange::getCharRange(Range),
-              *Result.SourceManager, Result.Context->getLangOpts())
+  return !Lexer::makeFileCharRange(CharSourceRange::getCharRange(Range),
+                                   *Result.SourceManager,
+                                   Result.Context->getLangOpts())
               .isValid();
 }
 
@@ -85,7 +85,7 @@ static bool parensRequired(const MatchFinder::MatchResult &Result,
 }
 
 void TimeSubtractionCheck::emitDiagnostic(const Expr *Node,
-                                          llvm::StringRef Replacement) {
+                                          StringRef Replacement) {
   diag(Node->getBeginLoc(), "perform subtraction in the time domain")
       << FixItHint::CreateReplacement(Node->getSourceRange(), Replacement);
 }
diff --git a/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.h b/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.h
index 3f44a3ded91e4..10850e7edde90 100644
--- a/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.h
+++ b/clang-tools-extra/clang-tidy/abseil/TimeSubtractionCheck.h
@@ -29,7 +29,7 @@ class TimeSubtractionCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  void emitDiagnostic(const Expr *Node, llvm::StringRef Replacement);
+  void emitDiagnostic(const Expr *Node, StringRef Replacement);
 };
 
 } // namespace clang::tidy::abseil
diff --git a/clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.cpp b/clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.cpp
index 698c3965366ce..3dcdbd37e7795 100644
--- a/clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.cpp
@@ -48,7 +48,7 @@ void UncheckedStatusOrAccessCheck::check(
     return;
 
   UncheckedStatusOrAccessDiagnoser Diagnoser;
-  if (llvm::Expected<llvm::SmallVector<SourceLocation>> Locs =
+  if (llvm::Expected<SmallVector<SourceLocation>> Locs =
           dataflow::diagnoseFunction<UncheckedStatusOrAccessModel,
                                      SourceLocation>(*FuncDecl, *Result.Context,
                                                      Diagnoser))
diff --git a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
index 1a6ff30fc8d96..be09ad9782399 100644
--- a/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/abseil/UpgradeDurationConversionsCheck.cpp
@@ -113,7 +113,7 @@ void UpgradeDurationConversionsCheck::registerMatchers(MatchFinder *Finder) {
 
 void UpgradeDurationConversionsCheck::check(
     const MatchFinder::MatchResult &Result) {
-  const llvm::StringRef Message =
+  static constexpr StringRef Message =
       "implicit conversion to 'int64_t' is deprecated in this context; use an "
       "explicit cast instead";
 
diff --git a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
index 22e8c03805e3f..4a12a44bbbf79 100644
--- a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
+++ b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
@@ -52,7 +52,7 @@ void StructPackAlignCheck::check(const MatchFinder::MatchResult &Result) {
     return;
 
   // Get sizing info for the struct.
-  llvm::SmallVector<std::pair<unsigned int, unsigned int>, 10> FieldSizes;
+  SmallVector<std::pair<unsigned int, unsigned int>, 10> FieldSizes;
   unsigned int TotalBitSize = 0;
   for (const FieldDecl *StructField : Struct->fields()) {
     // For each StructField, record how big it is (in bits).
@@ -73,7 +73,7 @@ void StructPackAlignCheck::check(const MatchFinder::MatchResult &Result) {
   const CharUnits CurrSize =
       Result.Context->getASTRecordLayout(Struct).getSize();
   const CharUnits MinByteSize =
-      CharUnits::fromQuantity(std::max<clang::CharUnits::QuantityType>(
+      CharUnits::fromQuantity(std::max<CharUnits::QuantityType>(
           std::ceil(static_cast<float>(TotalBitSize) / CharSize), 1));
   const CharUnits MaxAlign = CharUnits::fromQuantity(
       std::ceil(static_cast<float>(Struct->getMaxAlignment()) / CharSize));
diff --git a/clang-tools-extra/clang-tidy/boost/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/boost/UseRangesCheck.cpp
index a72d8a3d4f390..e976a7eecbfcb 100644
--- a/clang-tools-extra/clang-tidy/boost/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/boost/UseRangesCheck.cpp
@@ -207,7 +207,7 @@ utils::UseRangesCheck::ReplacerMap UseRangesCheck::getReplacerMap() const {
   const auto AddFrom =
       [&Results](llvm::IntrusiveRefCntPtr<UseRangesCheck::Replacer> Replacer,
                  std::initializer_list<StringRef> Names, StringRef Prefix) {
-        llvm::SmallString<64> Buffer;
+        SmallString<64> Buffer;
         for (const auto &Name : Names) {
           Buffer.assign({"::", Prefix, (Prefix.empty() ? "" : "::"), Name});
           Results.try_emplace(Buffer, Replacer);
diff --git a/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
index eb9b710b28549..e3139f96cfb09 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ArgumentCommentCheck.cpp
@@ -273,7 +273,7 @@ void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx,
     }
 
     for (const auto &Comment : Comments) {
-      llvm::SmallVector<StringRef, 2> Matches;
+      SmallVector<StringRef, 2> Matches;
       if (IdentRE.match(Comment.Text, &Matches) &&
           !sameName(Matches[2], II->getName(), StrictMode)) {
         {
@@ -297,7 +297,7 @@ void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx,
 
     // If the argument comments are missing for literals add them.
     if (Comments.empty() && shouldAddComment(Args[I])) {
-      llvm::SmallString<32> ArgComment;
+      SmallString<32> ArgComment;
       (llvm::Twine("/*") + II->getName() + "=*/").toStringRef(ArgComment);
       const DiagnosticBuilder Diag =
           diag(Args[I]->getBeginLoc(),
diff --git a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
index 6eadae21fae2f..574ccfc255a53 100644
--- a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
@@ -24,7 +24,7 @@ namespace clang::tidy::bugprone {
 namespace {
 
 AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
-               clang::ast_matchers::internal::Matcher<NamedDecl>,
+               ast_matchers::internal::Matcher<NamedDecl>,
                IgnoredFunctionsMatcher) {
   const Expr *E = &Node;
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp
index e1bca0e459c71..588f9bfe076df 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp
@@ -20,7 +20,7 @@ using namespace clang::ast_matchers;
 namespace {
 /// A branch in a switch may consist of several statements; while a branch in
 /// an if/else if/else chain is one statement (which may be a CompoundStmt).
-using SwitchBranch = llvm::SmallVector<const Stmt *, 2>;
+using SwitchBranch = SmallVector<const Stmt *, 2>;
 } // anonymous namespace
 
 /// Determines if the bodies of two branches in a switch statements are Type I
@@ -305,7 +305,7 @@ void BranchCloneCheck::check(const MatchFinder::MatchResult &Result) {
 
     // This is the complicated case when we start an if/else if/else chain.
     // To find all the duplicates, we collect all the branches into a vector.
-    llvm::SmallVector<const Stmt *, 4> Branches;
+    SmallVector<const Stmt *, 4> Branches;
     const IfStmt *Cur = IS;
     while (true) {
       // Store the `then` branch.
@@ -388,7 +388,7 @@ void BranchCloneCheck::check(const MatchFinder::MatchResult &Result) {
     // (`case:` or `default:`) children of Body; that is, we ignore `case:` or
     // `default:` labels embedded inside other statements and we do not follow
     // the effects of `break` and other manipulation of the control-flow.
-    llvm::SmallVector<SwitchBranch, 4> Branches;
+    SmallVector<SwitchBranch, 4> Branches;
     for (const Stmt *S : Body->body()) {
       // If this is a `case` or `default`, we start a new, empty branch.
       if (isa<SwitchCase>(S))
diff --git a/clang-tools-extra/clang-tidy/bugprone/ChainedComparisonCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ChainedComparisonCheck.cpp
index 8b1c8aaa48e3e..1c70fb482aa2d 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ChainedComparisonCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ChainedComparisonCheck.cpp
@@ -37,14 +37,14 @@ AST_MATCHER(CXXOperatorCallExpr,
 }
 
 struct ChainedComparisonData {
-  llvm::SmallString<256U> Name;
-  llvm::SmallVector<const Expr *, 32U> Operands;
+  SmallString<256U> Name;
+  SmallVector<const Expr *, 32U> Operands;
 
   explicit ChainedComparisonData(const Expr *Op) { extract(Op); }
 
 private:
   void add(const Expr *Operand);
-  void add(llvm::StringRef Opcode);
+  void add(StringRef Opcode);
   void extract(const Expr *Op);
   void extract(const BinaryOperator *Op);
   void extract(const CXXOperatorCallExpr *Op);
@@ -60,7 +60,7 @@ void ChainedComparisonData::add(const Expr *Operand) {
   Operands.push_back(Operand);
 }
 
-void ChainedComparisonData::add(llvm::StringRef Opcode) {
+void ChainedComparisonData::add(StringRef Opcode) {
   Name += ' ';
   Name += Opcode;
 }
@@ -148,7 +148,7 @@ void ChainedComparisonCheck::check(const MatchFinder::MatchResult &Result) {
        "chained comparison '%0' may generate unintended results, use "
        "parentheses to specify order of evaluation or a logical operator to "
        "separate comparison expressions")
-      << llvm::StringRef(Data.Name).trim() << MatchedOperator->getSourceRange();
+      << StringRef(Data.Name).trim() << MatchedOperator->getSourceRange();
 
   for (std::size_t Index = 0U; Index < Data.Operands.size(); ++Index) {
     diag(Data.Operands[Index]->getBeginLoc(), "operand 'v%0' is here",
diff --git a/clang-tools-extra/clang-tidy/bugprone/ComparePointerToMemberVirtualFunctionCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ComparePointerToMemberVirtualFunctionCheck.cpp
index 5e6eda674d35b..91290c2850c57 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ComparePointerToMemberVirtualFunctionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ComparePointerToMemberVirtualFunctionCheck.cpp
@@ -65,7 +65,7 @@ void ComparePointerToMemberVirtualFunctionCheck::check(
     return;
   }
   // compare with variable which type is pointer to member function.
-  llvm::SmallVector<SourceLocation, 12U> SameSignatureVirtualMethods{};
+  SmallVector<SourceLocation, 12U> SameSignatureVirtualMethods{};
   const auto *MPT = cast<MemberPointerType>(DRE->getType().getCanonicalType());
   const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
   if (RD == nullptr)
diff --git a/clang-tools-extra/clang-tidy/bugprone/DerivedMethodShadowingBaseMethodCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/DerivedMethodShadowingBaseMethodCheck.cpp
index 7c5867619cf4e..d50569fa70851 100644
--- a/clang-tools-extra/clang-tidy/bugprone/DerivedMethodShadowingBaseMethodCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/DerivedMethodShadowingBaseMethodCheck.cpp
@@ -43,14 +43,13 @@ namespace {
 AST_MATCHER(CXXMethodDecl, nameCollidesWithMethodInBase) {
   const CXXRecordDecl *DerivedClass = Node.getParent();
   for (const auto &Base : DerivedClass->bases()) {
-    llvm::SmallVector<const CXXBaseSpecifier *, 8> Stack;
+    SmallVector<const CXXBaseSpecifier *, 8> Stack;
     Stack.push_back(&Base);
     while (!Stack.empty()) {
       const CXXBaseSpecifier *CurrentBaseSpec = Stack.back();
       Stack.pop_back();
 
-      if (CurrentBaseSpec->getAccessSpecifier() ==
-          clang::AccessSpecifier::AS_private)
+      if (CurrentBaseSpec->getAccessSpecifier() == AccessSpecifier::AS_private)
         continue;
 
       const CXXRecordDecl *CurrentRecord =
@@ -66,8 +65,7 @@ AST_MATCHER(CXXMethodDecl, nameCollidesWithMethodInBase) {
       for (const auto &BaseMethod : CurrentRecord->methods()) {
         if (namesCollide(*BaseMethod, Node)) {
           const ast_matchers::internal::BoundNodesTreeBuilder Result(*Builder);
-          Builder->setBinding("base_method",
-                              clang::DynTypedNode::create(*BaseMethod));
+          Builder->setBinding("base_method", DynTypedNode::create(*BaseMethod));
           return true;
         }
       }
diff --git a/clang-tools-extra/clang-tidy/bugprone/DynamicStaticInitializersCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/DynamicStaticInitializersCheck.cpp
index d40662ab0e7ad..ebbc197e0189a 100644
--- a/clang-tools-extra/clang-tidy/bugprone/DynamicStaticInitializersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/DynamicStaticInitializersCheck.cpp
@@ -17,7 +17,7 @@ namespace clang::tidy::bugprone {
 
 namespace {
 
-AST_MATCHER(clang::VarDecl, hasConstantDeclaration) {
+AST_MATCHER(VarDecl, hasConstantDeclaration) {
   if (Node.isConstexpr() || Node.hasAttr<ConstInitAttr>())
     return true;
   if (const VarDecl *Def = Node.getDefinition();
diff --git a/clang-tools-extra/clang-tidy/bugprone/EasilySwappableParametersCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/EasilySwappableParametersCheck.cpp
index 7774c34927ce1..e95af89375dc8 100644
--- a/clang-tools-extra/clang-tidy/bugprone/EasilySwappableParametersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/EasilySwappableParametersCheck.cpp
@@ -1198,7 +1198,7 @@ class UserDefinedConversionSelector {
   }
 
 private:
-  llvm::SmallVector<PreparedConversion, 2> FlaggedConversions;
+  SmallVector<PreparedConversion, 2> FlaggedConversions;
   const TheCheck &Check;
 };
 
@@ -1740,7 +1740,7 @@ class AccessedSameMemberOf {
 /// Implements the heuristic that marks two parameters related if different
 /// ReturnStmts return them from the function.
 class Returned {
-  llvm::SmallVector<const ParmVarDecl *, SmallDataStructureSize> ReturnedParams;
+  SmallVector<const ParmVarDecl *, SmallDataStructureSize> ReturnedParams;
 
 public:
   void setup(const FunctionDecl *FD) {
diff --git a/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.cpp
index 5cf7cfeb3cd39..9e5e1219b6387 100644
--- a/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.cpp
@@ -35,8 +35,7 @@ AST_MATCHER_P(CXXCatchStmt, hasCaughtType, Matcher<QualType>, InnerMatcher) {
   return InnerMatcher.matches(Node.getCaughtType(), Finder, Builder);
 }
 
-AST_MATCHER_P(CompoundStmt, hasAnyTextFromList, std::vector<llvm::StringRef>,
-              List) {
+AST_MATCHER_P(CompoundStmt, hasAnyTextFromList, std::vector<StringRef>, List) {
   if (List.empty())
     return false;
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.h b/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.h
index db8ee02dfd404..293bc5675a2a6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/EmptyCatchCheck.h
@@ -28,8 +28,8 @@ class EmptyCatchCheck : public ClangTidyCheck {
   std::optional<TraversalKind> getCheckTraversalKind() const override;
 
 private:
-  std::vector<llvm::StringRef> IgnoreCatchWithKeywords;
-  std::vector<llvm::StringRef> AllowEmptyCatchForExceptions;
+  std::vector<StringRef> IgnoreCatchWithKeywords;
+  std::vector<StringRef> AllowEmptyCatchForExceptions;
 };
 
 } // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
index 41e0cdaf6ee61..e4facdad2c7aa 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ExceptionEscapeCheck.cpp
@@ -68,7 +68,7 @@ ExceptionEscapeCheck::ExceptionEscapeCheck(StringRef Name,
       TreatFunctionsWithoutSpecificationAsThrowing(
           Options.get("TreatFunctionsWithoutSpecificationAsThrowing",
                       TreatFunctionsWithoutSpecification::None)) {
-  llvm::SmallVector<StringRef, 8> FunctionsThatShouldNotThrowVec,
+  SmallVector<StringRef, 8> FunctionsThatShouldNotThrowVec,
       IgnoredExceptionsVec, CheckedSwapFunctionsVec;
   RawFunctionsThatShouldNotThrow.split(FunctionsThatShouldNotThrowVec, ",", -1,
                                        false);
diff --git a/clang-tools-extra/clang-tidy/bugprone/ForwardingReferenceOverloadCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ForwardingReferenceOverloadCheck.cpp
index 263ab635d9458..8d4d9d67f17f4 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ForwardingReferenceOverloadCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ForwardingReferenceOverloadCheck.cpp
@@ -46,7 +46,7 @@ AST_MATCHER(QualType, isEnableIf) {
   return false;
 }
 AST_MATCHER_P(TemplateTypeParmDecl, hasDefaultArgument,
-              clang::ast_matchers::internal::Matcher<QualType>, TypeMatcher) {
+              ast_matchers::internal::Matcher<QualType>, TypeMatcher) {
   return Node.hasDefaultArgument() &&
          TypeMatcher.matches(
              Node.getDefaultArgument().getArgument().getAsType(), Finder,
diff --git a/clang-tools-extra/clang-tidy/bugprone/IncorrectEnableSharedFromThisCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/IncorrectEnableSharedFromThisCheck.cpp
index 5ded16a019618..57961724bf1be 100644
--- a/clang-tools-extra/clang-tidy/bugprone/IncorrectEnableSharedFromThisCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/IncorrectEnableSharedFromThisCheck.cpp
@@ -44,7 +44,7 @@ void IncorrectEnableSharedFromThisCheck::check(
       BaseSpec->getAccessSpecifierAsWritten() != AS_none;
   const auto ReplacementRange = CharSourceRange(
       SourceRange(BaseSpec->getBeginLoc()), HasWrittenAccessSpecifier);
-  const llvm::StringRef Replacement =
+  const StringRef Replacement =
       HasWrittenAccessSpecifier ? "public" : "public ";
   const FixItHint Hint =
       IsEnableSharedFromThisDirectBase
diff --git a/clang-tools-extra/clang-tidy/bugprone/NarrowingConversionsCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/NarrowingConversionsCheck.cpp
index 2bc4545f439f0..f0a0f6c9b3106 100644
--- a/clang-tools-extra/clang-tidy/bugprone/NarrowingConversionsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/NarrowingConversionsCheck.cpp
@@ -299,13 +299,13 @@ static bool isFloatExactlyRepresentable(const ASTContext &Context,
   return !Overflows && IsExact;
 }
 
-static llvm::SmallString<64> getValueAsString(const llvm::APSInt &Value,
-                                              uint64_t HexBits) {
-  llvm::SmallString<64> Str;
+static SmallString<64> getValueAsString(const llvm::APSInt &Value,
+                                        uint64_t HexBits) {
+  SmallString<64> Str;
   Value.toString(Str, 10);
   if (HexBits > 0) {
     Str.append(" (0x");
-    llvm::SmallString<32> HexValue;
+    SmallString<32> HexValue;
     Value.toStringUnsigned(HexValue, 16);
     for (size_t I = HexValue.size(); I < (HexBits / 4); ++I)
       Str.append("0");
@@ -550,7 +550,7 @@ void NarrowingConversionsCheck::handleBinaryOperator(const ASTContext &Context,
 
 bool NarrowingConversionsCheck::handleConditionalOperator(
     const ASTContext &Context, const Expr &Lhs, const Expr &Rhs) {
-  if (const auto *CO = llvm::dyn_cast<ConditionalOperator>(&Rhs)) {
+  if (const auto *CO = dyn_cast<ConditionalOperator>(&Rhs)) {
     // We have an expression like so: `output = cond ? lhs : rhs`
     // From the point of view of narrowing conversion we treat it as two
     // expressions `output = lhs` and `output = rhs`.
@@ -563,7 +563,7 @@ bool NarrowingConversionsCheck::handleConditionalOperator(
 
 void NarrowingConversionsCheck::handleConditionalOperatorArgument(
     const ASTContext &Context, const Expr &Lhs, const Expr *Arg) {
-  if (const auto *ICE = llvm::dyn_cast<ImplicitCastExpr>(Arg))
+  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(Arg))
     if (!Arg->getIntegerConstantExpr(Context))
       Arg = ICE->getSubExpr();
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/OptionalValueConversionCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/OptionalValueConversionCheck.cpp
index 9cd8930394a2f..446e62e41d16c 100644
--- a/clang-tools-extra/clang-tidy/bugprone/OptionalValueConversionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/OptionalValueConversionCheck.cpp
@@ -153,7 +153,7 @@ void OptionalValueConversionCheck::check(
          << FixItHint::CreateRemoval(
                 CharSourceRange::getTokenRange(Begin, CallExpr->getEndLoc()));
     if (const auto *Member =
-            llvm::dyn_cast<MemberExpr>(CallExpr->getCallee()->IgnoreImplicit());
+            dyn_cast<MemberExpr>(CallExpr->getCallee()->IgnoreImplicit());
         Member && Member->isArrow())
       Diag << FixItHint::CreateInsertion(CallExpr->getBeginLoc(), "*");
     return;
diff --git a/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
index 3c0ced96c05ac..55e926ed12966 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ParentVirtualCallCheck.cpp
@@ -18,7 +18,7 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::bugprone {
 
-using BasesVector = llvm::SmallVector<const CXXRecordDecl *, 5>;
+using BasesVector = SmallVector<const CXXRecordDecl *, 5>;
 
 static bool isParentOf(const CXXRecordDecl &Parent,
                        const CXXRecordDecl &ThisClass) {
@@ -66,8 +66,7 @@ static std::string getNameAsString(const NamedDecl *Decl) {
 
 // Returns E as written in the source code. Used to handle 'using' and
 // 'typedef'ed names of grand-parent classes.
-static std::string getExprAsString(const clang::Expr &E,
-                                   clang::ASTContext &AC) {
+static std::string getExprAsString(const Expr &E, ASTContext &AC) {
   std::string Text = tooling::fixit::getText(E, AC).str();
   llvm::erase_if(Text, [](char C) {
     return llvm::isSpace(static_cast<unsigned char>(C));
diff --git a/clang-tools-extra/clang-tidy/bugprone/RawMemoryCallOnNonTrivialTypeCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/RawMemoryCallOnNonTrivialTypeCheck.cpp
index e212301047ce2..59942a9fb12e6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/RawMemoryCallOnNonTrivialTypeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/RawMemoryCallOnNonTrivialTypeCheck.cpp
@@ -44,7 +44,7 @@ static const char BuiltinMemCmp[] = "::std::memcmp;"
                                     "::std::strcmp;"
                                     "::strcmp;"
                                     "::strncmp;";
-static constexpr llvm::StringRef ComparisonOperators[] = {
+static constexpr StringRef ComparisonOperators[] = {
     "operator==", "operator!=", "operator<",
     "operator>",  "operator<=", "operator>="};
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
index 62e22450800ea..f8db3602f0ec7 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
@@ -37,9 +37,9 @@ static int getMessageSelectIndex(StringRef Tag) {
   return 0;
 }
 
-llvm::SmallVector<llvm::Regex>
+SmallVector<llvm::Regex>
 ReservedIdentifierCheck::parseAllowedIdentifiers() const {
-  llvm::SmallVector<llvm::Regex> AllowedIdentifiers;
+  SmallVector<llvm::Regex> AllowedIdentifiers;
   AllowedIdentifiers.reserve(AllowedIdentifiersRaw.size());
 
   for (const auto &Identifier : AllowedIdentifiersRaw) {
diff --git a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.h b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.h
index 89e2c86f99a8f..49de2442d530e 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.h
@@ -31,7 +31,7 @@ namespace clang::tidy::bugprone {
 class ReservedIdentifierCheck final : public RenamerClangTidyCheck {
   const bool Invert;
   const std::vector<StringRef> AllowedIdentifiersRaw;
-  const llvm::SmallVector<llvm::Regex> AllowedIdentifiers;
+  const SmallVector<llvm::Regex> AllowedIdentifiers;
 
 public:
   ReservedIdentifierCheck(StringRef Name, ClangTidyContext *Context);
@@ -47,7 +47,7 @@ class ReservedIdentifierCheck final : public RenamerClangTidyCheck {
                       const SourceManager &SM) const override;
   DiagInfo getDiagInfo(const NamingCheckId &ID,
                        const NamingCheckFailure &Failure) const override;
-  llvm::SmallVector<llvm::Regex> parseAllowedIdentifiers() const;
+  SmallVector<llvm::Regex> parseAllowedIdentifiers() const;
 };
 
 } // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp
index 2b9a8d36c2835..dda687ff7ade5 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp
@@ -65,7 +65,7 @@ static bool hasSameParameterTypes(const FunctionDecl &FD, const FunctionDecl &O,
     const ParmVarDecl *DPD = FD.getParamDecl(I);
     const QualType OPT = O.getParamDecl(I)->getType();
     if (DPD == &PD) {
-      if (!llvm::isa<RValueReferenceType>(OPT) ||
+      if (!isa<RValueReferenceType>(OPT) ||
           !isSameTypeIgnoringConstRef(DPD->getType(), OPT))
         return false;
     } else {
diff --git a/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp
index 6479ede6bf606..0f9a5f967c153 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp
@@ -532,7 +532,7 @@ bool SignalHandlerCheck::isStandardFunctionAsyncSafe(
 }
 
 void SignalHandlerCheck::reportHandlerChain(
-    const llvm::df_iterator<const clang::CallGraphNode *> &Itr,
+    const llvm::df_iterator<const CallGraphNode *> &Itr,
     const DeclRefExpr *HandlerRef, bool SkipPathEnd) {
   int CallLevel = Itr.getPathLength() - 2;
   assert(CallLevel >= -1 && "Empty iterator?");
diff --git a/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h b/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h
index 324b2c88207fd..6833cae6879d4 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h
@@ -65,11 +65,10 @@ class SignalHandlerCheck : public ClangTidyCheck {
   /// registered as signal handler.
   /// @param SkipPathEnd If true the last item of the call chain (farthest away
   /// from the \c signal call) is omitted from note generation.
-  void
-  reportHandlerChain(const llvm::df_iterator<const clang::CallGraphNode *> &Itr,
-                     const DeclRefExpr *HandlerRef, bool SkipPathEnd);
+  void reportHandlerChain(const llvm::df_iterator<const CallGraphNode *> &Itr,
+                          const DeclRefExpr *HandlerRef, bool SkipPathEnd);
 
-  clang::CallGraph CG;
+  CallGraph CG;
 
   AsyncSafeFunctionSetKind AsyncSafeFunctionSet;
   llvm::StringSet<> ConformingFunctions;
diff --git a/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.cpp
index 31c5413b8aa4c..88a2614b266b9 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.cpp
@@ -32,8 +32,8 @@ void SignedCharMisuseCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
 }
 
 // Create a matcher for char -> integer cast.
-BindableMatcher<clang::Stmt> SignedCharMisuseCheck::charCastExpression(
-    bool IsSigned, const Matcher<clang::QualType> &IntegerType,
+BindableMatcher<Stmt> SignedCharMisuseCheck::charCastExpression(
+    bool IsSigned, const Matcher<QualType> &IntegerType,
     const std::string &CastBindName) const {
   // We can ignore typedefs which are some kind of integer types
   // (e.g. typedef char sal_Int8). In this case, we don't need to
diff --git a/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.h b/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.h
index c6d9f29523c5e..970c2aa5f8e0b 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/SignedCharMisuseCheck.h
@@ -30,9 +30,9 @@ class SignedCharMisuseCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  ast_matchers::internal::BindableMatcher<clang::Stmt> charCastExpression(
+  ast_matchers::internal::BindableMatcher<Stmt> charCastExpression(
       bool IsSigned,
-      const ast_matchers::internal::Matcher<clang::QualType> &IntegerType,
+      const ast_matchers::internal::Matcher<QualType> &IntegerType,
       const std::string &CastBindName) const;
 
   const StringRef CharTypedefsToIgnoreList;
diff --git a/clang-tools-extra/clang-tidy/bugprone/SmartPtrArrayMismatchCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SmartPtrArrayMismatchCheck.cpp
index af478b105fdd1..a0db39ab6f90d 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SmartPtrArrayMismatchCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/SmartPtrArrayMismatchCheck.cpp
@@ -89,7 +89,7 @@ void SmartPtrArrayMismatchCheck::check(const MatchFinder::MatchResult &Result) {
   if (VarOrField) {
     auto TSTypeLoc = VarOrField->getTypeSourceInfo()
                          ->getTypeLoc()
-                         .getAsAdjusted<clang::TemplateSpecializationTypeLoc>();
+                         .getAsAdjusted<TemplateSpecializationTypeLoc>();
     assert(TSTypeLoc.getNumArgs() >= 1 &&
            "Matched type should have at least 1 template argument.");
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
index 056ae4b80f109..1d72f3e9f387b 100644
--- a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
@@ -129,14 +129,13 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     auto Candidates = HeuristicResolver(Context).lookupDependentName(
         MemberCall->getRecordDecl(), Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
-                 llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
-                     0 &&
-                 !llvm::cast<CXXMethodDecl>(ND)->isConst();
+                 cast<CXXMethodDecl>(ND)->getMinRequiredArguments() == 0 &&
+                 !cast<CXXMethodDecl>(ND)->isConst();
         });
 
     const bool HasClear = !Candidates.empty();
     if (HasClear) {
-      const auto *Clear = llvm::cast<CXXMethodDecl>(Candidates.at(0));
+      const auto *Clear = cast<CXXMethodDecl>(Candidates.at(0));
       const QualType RangeType =
           MemberCall->getImplicitObjectArgument()->getType();
       const bool QualifierIncompatible =
@@ -179,15 +178,14 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     auto Candidates = HeuristicResolver(Context).lookupDependentName(
         ArgRecordDecl, Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
-                 llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
-                     0 &&
-                 !llvm::cast<CXXMethodDecl>(ND)->isConst();
+                 cast<CXXMethodDecl>(ND)->getMinRequiredArguments() == 0 &&
+                 !cast<CXXMethodDecl>(ND)->isConst();
         });
 
     const bool HasClear = !Candidates.empty();
 
     if (HasClear) {
-      const auto *Clear = llvm::cast<CXXMethodDecl>(Candidates.at(0));
+      const auto *Clear = cast<CXXMethodDecl>(Candidates.at(0));
       const bool QualifierIncompatible =
           (!Clear->isVolatile() && Arg->getType().isVolatileQualified()) ||
           Arg->getType().isConstQualified();
@@ -201,7 +199,7 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
             SourceRange(NonMemberLoc, NonMemberEndLoc);
         diag(NonMemberLoc,
              "ignoring the result of '%0'; did you mean 'clear()'?")
-            << llvm::dyn_cast<NamedDecl>(NonMemberCall->getCalleeDecl())
+            << dyn_cast<NamedDecl>(NonMemberCall->getCalleeDecl())
                    ->getQualifiedNameAsString()
             << FixItHint::CreateReplacement(ReplacementRange, ReplacementText);
         return;
@@ -209,7 +207,7 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     }
 
     diag(NonMemberLoc, "ignoring the result of '%0'")
-        << llvm::dyn_cast<NamedDecl>(NonMemberCall->getCalleeDecl())
+        << dyn_cast<NamedDecl>(NonMemberCall->getCalleeDecl())
                ->getQualifiedNameAsString();
   }
 }
diff --git a/clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.cpp
index 8a79db184e87a..4c167eb4892c5 100644
--- a/clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.cpp
@@ -19,9 +19,9 @@ AST_POLYMORPHIC_MATCHER_P(
     hasAnyTemplateArgumentIncludingPack,
     AST_POLYMORPHIC_SUPPORTED_TYPES(ClassTemplateSpecializationDecl,
                                     TemplateSpecializationType, FunctionDecl),
-    clang::ast_matchers::internal::Matcher<TemplateArgument>, InnerMatcher) {
+    ast_matchers::internal::Matcher<TemplateArgument>, InnerMatcher) {
   const ArrayRef<TemplateArgument> Args =
-      clang::ast_matchers::internal::getTemplateSpecializationArgs(Node);
+      ast_matchers::internal::getTemplateSpecializationArgs(Node);
   for (const auto &Arg : Args) {
     if (Arg.getKind() != TemplateArgument::Pack)
       continue;
diff --git a/clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
index faa07fff5a369..6da20d3f6fecb 100644
--- a/clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
@@ -27,8 +27,8 @@ AST_MATCHER_P(InitListExpr, initCountIs, unsigned, N) {
   return Node.getNumInits() == N;
 }
 
-AST_MATCHER(clang::VarDecl, isDirectInitialization) {
-  return Node.getInitStyle() != clang::VarDecl::InitializationStyle::CInit;
+AST_MATCHER(VarDecl, isDirectInitialization) {
+  return Node.getInitStyle() != VarDecl::InitializationStyle::CInit;
 }
 
 } // namespace
@@ -59,7 +59,7 @@ static RewriteRuleWith<std::string> stringviewNullptrCheckImpl() {
 
   // Matches `nullptr` and `(nullptr)` binding to a pointer
   auto NullLiteral = implicitCastExpr(
-      hasCastKind(clang::CK_NullToPointer),
+      hasCastKind(CK_NullToPointer),
       hasSourceExpression(ignoringParens(cxxNullPtrLiteralExpr())));
 
   // Matches `{nullptr}` and `{(nullptr)}` binding to a pointer
@@ -233,7 +233,7 @@ static RewriteRuleWith<std::string> stringviewNullptrCheckImpl() {
       cxxOperatorCallExpr(
           hasOverloadedOperatorName("=="),
           hasOperands(ignoringImpCasts(BasicStringViewConstructingFromNullExpr),
-                      traverse(clang::TK_IgnoreUnlessSpelledInSource,
+                      traverse(TK_IgnoreUnlessSpelledInSource,
                                expr().bind("instance"))))
           .bind("root"),
       changeTo(node("root"), cat(access("instance", cat("empty")), "()")),
@@ -244,7 +244,7 @@ static RewriteRuleWith<std::string> stringviewNullptrCheckImpl() {
       cxxOperatorCallExpr(
           hasOverloadedOperatorName("!="),
           hasOperands(ignoringImpCasts(BasicStringViewConstructingFromNullExpr),
-                      traverse(clang::TK_IgnoreUnlessSpelledInSource,
+                      traverse(TK_IgnoreUnlessSpelledInSource,
                                expr().bind("instance"))))
           .bind("root"),
       changeTo(node("root"), cat("!", access("instance", cat("empty")), "()")),
diff --git a/clang-tools-extra/clang-tidy/bugprone/SuspiciousStringviewDataUsageCheck.h b/clang-tools-extra/clang-tidy/bugprone/SuspiciousStringviewDataUsageCheck.h
index eae8aad5b7d3e..ee7301f77611b 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SuspiciousStringviewDataUsageCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/SuspiciousStringviewDataUsageCheck.h
@@ -29,8 +29,8 @@ class SuspiciousStringviewDataUsageCheck : public ClangTidyCheck {
   std::optional<TraversalKind> getCheckTraversalKind() const override;
 
 private:
-  std::vector<llvm::StringRef> StringViewTypes;
-  std::vector<llvm::StringRef> AllowedCallees;
+  std::vector<StringRef> StringViewTypes;
+  std::vector<StringRef> AllowedCallees;
 };
 
 } // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/TaggedUnionMemberCountCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TaggedUnionMemberCountCheck.cpp
index 3e43a1802c43f..0c64b68fba591 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TaggedUnionMemberCountCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TaggedUnionMemberCountCheck.cpp
@@ -43,7 +43,7 @@ AST_MATCHER_P2(RecordDecl, fieldCountOfKindIsOne,
   // is used for matching.
   //
   // For precedence, see commit: 5b07de1a5faf4a22ae6fd982b877c5e7e3a76559
-  clang::ast_matchers::internal::BoundNodesTreeBuilder TempBuilder;
+  ast_matchers::internal::BoundNodesTreeBuilder TempBuilder;
 
   const FieldDecl *FirstMatch = nullptr;
   for (const FieldDecl *Field : Node.fields()) {
@@ -55,7 +55,7 @@ AST_MATCHER_P2(RecordDecl, fieldCountOfKindIsOne,
   }
 
   if (FirstMatch) {
-    Builder->setBinding(BindName, clang::DynTypedNode::create(*FirstMatch));
+    Builder->setBinding(BindName, DynTypedNode::create(*FirstMatch));
     return true;
   }
   return false;
diff --git a/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.cpp
index 6521a95d2b80f..79d6e4974c316 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessCheck.cpp
@@ -53,9 +53,9 @@ void UncheckedOptionalAccessCheck::check(
   UncheckedOptionalAccessDiagnoser Diagnoser(ModelOptions);
   // FIXME: Allow user to set the (defaulted) SAT iterations max for
   // `diagnoseFunction` with config options.
-  if (llvm::Expected<llvm::SmallVector<UncheckedOptionalAccessDiagnostic>>
-          Diags = dataflow::diagnoseFunction<UncheckedOptionalAccessModel,
-                                             UncheckedOptionalAccessDiagnostic>(
+  if (llvm::Expected<SmallVector<UncheckedOptionalAccessDiagnostic>> Diags =
+          dataflow::diagnoseFunction<UncheckedOptionalAccessModel,
+                                     UncheckedOptionalAccessDiagnostic>(
               *FuncDecl, *Result.Context, Diagnoser))
     for (const UncheckedOptionalAccessDiagnostic &Diag : *Diags) {
       diag(Diag.Range.getBegin(), "unchecked access to optional value")
diff --git a/clang-tools-extra/clang-tidy/bugprone/UnintendedCharOstreamOutputCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/UnintendedCharOstreamOutputCheck.cpp
index e10b17ca20753..5056172cd38a6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UnintendedCharOstreamOutputCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/UnintendedCharOstreamOutputCheck.cpp
@@ -90,7 +90,7 @@ void UnintendedCharOstreamOutputCheck::check(
   const QualType T = Value->getType();
   const Type *UnqualifiedDesugaredType = T->getUnqualifiedDesugaredType();
 
-  const llvm::StringRef CastType = CastTypeName.value_or(
+  const StringRef CastType = CastTypeName.value_or(
       UnqualifiedDesugaredType->isSpecificBuiltinType(BuiltinType::SChar)
           ? "int"
           : "unsigned int");
diff --git a/clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.cpp
index 52d11309c7842..0bce3be13eef6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.cpp
@@ -228,7 +228,7 @@ void UnsafeFunctionsCheck::registerMatchers(MatchFinder *Finder) {
   }
 
   if (!CustomFunctions.empty()) {
-    std::vector<llvm::StringRef> FunctionNames;
+    std::vector<StringRef> FunctionNames;
     FunctionNames.reserve(CustomFunctions.size());
 
     for (const auto &Entry : CustomFunctions)
diff --git a/clang-tools-extra/clang-tidy/bugprone/UnsafeToAllowExceptionsCheck.h b/clang-tools-extra/clang-tidy/bugprone/UnsafeToAllowExceptionsCheck.h
index d91d48427ce4a..5d113b2f6ce65 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UnsafeToAllowExceptionsCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/UnsafeToAllowExceptionsCheck.h
@@ -29,7 +29,7 @@ class UnsafeToAllowExceptionsCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::vector<llvm::StringRef> CheckedSwapFunctions;
+  std::vector<StringRef> CheckedSwapFunctions;
 };
 
 } // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
index 7aee725cae434..c5792cd17b9b2 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
@@ -44,7 +44,7 @@ AST_MATCHER(FunctionDecl, isAssignmentOverloadedOperator) {
 }
 } // namespace
 
-UnusedReturnValueCheck::UnusedReturnValueCheck(llvm::StringRef Name,
+UnusedReturnValueCheck::UnusedReturnValueCheck(StringRef Name,
                                                ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
       CheckedFunctions(utils::options::parseStringList(
@@ -148,13 +148,13 @@ UnusedReturnValueCheck::UnusedReturnValueCheck(llvm::StringRef Name,
       AllowCastToVoid(Options.get("AllowCastToVoid", false)) {}
 
 UnusedReturnValueCheck::UnusedReturnValueCheck(
-    llvm::StringRef Name, ClangTidyContext *Context,
+    StringRef Name, ClangTidyContext *Context,
     std::vector<StringRef> CheckedFunctions)
     : UnusedReturnValueCheck(Name, Context, std::move(CheckedFunctions), {},
                              false) {}
 
 UnusedReturnValueCheck::UnusedReturnValueCheck(
-    llvm::StringRef Name, ClangTidyContext *Context,
+    StringRef Name, ClangTidyContext *Context,
     std::vector<StringRef> CheckedFunctions,
     std::vector<StringRef> CheckedReturnTypes, bool AllowCastToVoid)
     : ClangTidyCheck(Name, Context),
diff --git a/clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
index 7dc648f8ed405..8e9f48ee0cd21 100644
--- a/clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/UseAfterMoveCheck.cpp
@@ -65,7 +65,7 @@ class UseAfterMoveFinder {
                                            const Expr *MovingCall,
                                            const ValueDecl *MovedVariable);
   void getUsesAndReinits(const CFGBlock *Block, const ValueDecl *MovedVariable,
-                         llvm::SmallVectorImpl<const DeclRefExpr *> *Uses,
+                         SmallVectorImpl<const DeclRefExpr *> *Uses,
                          llvm::SmallPtrSetImpl<const Stmt *> *Reinits);
   void getDeclRefs(const CFGBlock *Block, const Decl *MovedVariable,
                    llvm::SmallPtrSetImpl<const DeclRefExpr *> *DeclRefs);
@@ -133,9 +133,9 @@ makeReinitMatcher(const ValueDecl *MovedVariable,
                                            StandardResettableOwnerTypeMatcher)),
                                    callee(cxxMethodDecl(hasName("reset")))),
                  // Methods that have the [[clang::reinitializes]] attribute.
-                 cxxMemberCallExpr(on(DeclRefMatcher),
-                                   callee(cxxMethodDecl(
-                                       hasAttr(clang::attr::Reinitializes)))),
+                 cxxMemberCallExpr(
+                     on(DeclRefMatcher),
+                     callee(cxxMethodDecl(hasAttr(attr::Reinitializes)))),
                  // Functions that are specified in ReinitializationFunctions
                  // option.
                  callExpr(
@@ -243,7 +243,7 @@ UseAfterMoveFinder::findInternal(const CFGBlock *Block, const Expr *MovingCall,
     Visited.insert(Block);
 
   // Get all uses and reinits in the block.
-  llvm::SmallVector<const DeclRefExpr *, 1> Uses;
+  SmallVector<const DeclRefExpr *, 1> Uses;
   llvm::SmallPtrSet<const Stmt *, 1> Reinits;
   getUsesAndReinits(Block, MovedVariable, &Uses, &Reinits);
 
@@ -251,7 +251,7 @@ UseAfterMoveFinder::findInternal(const CFGBlock *Block, const Expr *MovingCall,
   // reinit.
   // If `Reinit` is identical to `MovingCall`, we're looking at a move-to-self
   // (e.g. `a = std::move(a)`). Count these as reinitializations.
-  llvm::SmallVector<const Stmt *, 1> ReinitsToDelete;
+  SmallVector<const Stmt *, 1> ReinitsToDelete;
   for (const Stmt *Reinit : Reinits)
     if (MovingCall && Reinit != MovingCall &&
         Sequence->potentiallyAfter(MovingCall, Reinit))
@@ -303,7 +303,7 @@ UseAfterMoveFinder::findInternal(const CFGBlock *Block, const Expr *MovingCall,
 
 void UseAfterMoveFinder::getUsesAndReinits(
     const CFGBlock *Block, const ValueDecl *MovedVariable,
-    llvm::SmallVectorImpl<const DeclRefExpr *> *Uses,
+    SmallVectorImpl<const DeclRefExpr *> *Uses,
     llvm::SmallPtrSetImpl<const Stmt *> *Reinits) {
   llvm::SmallPtrSet<const DeclRefExpr *, 1> DeclRefs;
   llvm::SmallPtrSet<const DeclRefExpr *, 1> ReinitDeclRefs;
@@ -550,7 +550,7 @@ void UseAfterMoveCheck::check(const MatchFinder::MatchResult &Result) {
     return;
 
   // Collect all code blocks that could use the arg after move.
-  llvm::SmallVector<Stmt *> CodeBlocks{};
+  SmallVector<Stmt *> CodeBlocks{};
   if (ContainingCtor) {
     CodeBlocks.push_back(ContainingCtor->getBody());
     if (ContainingCtorInit) {
diff --git a/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp b/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
index f64cb47d18b4e..8b62ef69e1290 100644
--- a/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
@@ -42,194 +42,191 @@
 #include "../readability/EnumInitialValueCheck.h"
 #include "../readability/UppercaseLiteralSuffixCheck.h"
 
-namespace {
+namespace clang::tidy {
 
 // Checked functions for cert-err33-c.
 // The following functions are deliberately excluded because they can be
 // called with NULL argument and in this case the check is not applicable:
 // `mblen, mbrlen, mbrtowc, mbtowc, wctomb, wctomb_s`.
 // FIXME: The check can be improved to handle such cases.
-const llvm::StringRef CertErr33CCheckedFunctions = "^::aligned_alloc$;"
-                                                   "^::asctime_s$;"
-                                                   "^::at_quick_exit$;"
-                                                   "^::atexit$;"
-                                                   "^::bsearch$;"
-                                                   "^::bsearch_s$;"
-                                                   "^::btowc$;"
-                                                   "^::c16rtomb$;"
-                                                   "^::c32rtomb$;"
-                                                   "^::calloc$;"
-                                                   "^::clock$;"
-                                                   "^::cnd_broadcast$;"
-                                                   "^::cnd_init$;"
-                                                   "^::cnd_signal$;"
-                                                   "^::cnd_timedwait$;"
-                                                   "^::cnd_wait$;"
-                                                   "^::ctime_s$;"
-                                                   "^::fclose$;"
-                                                   "^::fflush$;"
-                                                   "^::fgetc$;"
-                                                   "^::fgetpos$;"
-                                                   "^::fgets$;"
-                                                   "^::fgetwc$;"
-                                                   "^::fopen$;"
-                                                   "^::fopen_s$;"
-                                                   "^::fprintf$;"
-                                                   "^::fprintf_s$;"
-                                                   "^::fputc$;"
-                                                   "^::fputs$;"
-                                                   "^::fputwc$;"
-                                                   "^::fputws$;"
-                                                   "^::fread$;"
-                                                   "^::freopen$;"
-                                                   "^::freopen_s$;"
-                                                   "^::fscanf$;"
-                                                   "^::fscanf_s$;"
-                                                   "^::fseek$;"
-                                                   "^::fsetpos$;"
-                                                   "^::ftell$;"
-                                                   "^::fwprintf$;"
-                                                   "^::fwprintf_s$;"
-                                                   "^::fwrite$;"
-                                                   "^::fwscanf$;"
-                                                   "^::fwscanf_s$;"
-                                                   "^::getc$;"
-                                                   "^::getchar$;"
-                                                   "^::getenv$;"
-                                                   "^::getenv_s$;"
-                                                   "^::gets_s$;"
-                                                   "^::getwc$;"
-                                                   "^::getwchar$;"
-                                                   "^::gmtime$;"
-                                                   "^::gmtime_s$;"
-                                                   "^::localtime$;"
-                                                   "^::localtime_s$;"
-                                                   "^::malloc$;"
-                                                   "^::mbrtoc16$;"
-                                                   "^::mbrtoc32$;"
-                                                   "^::mbsrtowcs$;"
-                                                   "^::mbsrtowcs_s$;"
-                                                   "^::mbstowcs$;"
-                                                   "^::mbstowcs_s$;"
-                                                   "^::memchr$;"
-                                                   "^::mktime$;"
-                                                   "^::mtx_init$;"
-                                                   "^::mtx_lock$;"
-                                                   "^::mtx_timedlock$;"
-                                                   "^::mtx_trylock$;"
-                                                   "^::mtx_unlock$;"
-                                                   "^::printf_s$;"
-                                                   "^::putc$;"
-                                                   "^::putwc$;"
-                                                   "^::raise$;"
-                                                   "^::realloc$;"
-                                                   "^::remove$;"
-                                                   "^::rename$;"
-                                                   "^::scanf$;"
-                                                   "^::scanf_s$;"
-                                                   "^::setlocale$;"
-                                                   "^::setvbuf$;"
-                                                   "^::signal$;"
-                                                   "^::snprintf$;"
-                                                   "^::snprintf_s$;"
-                                                   "^::sprintf$;"
-                                                   "^::sprintf_s$;"
-                                                   "^::sscanf$;"
-                                                   "^::sscanf_s$;"
-                                                   "^::strchr$;"
-                                                   "^::strerror_s$;"
-                                                   "^::strftime$;"
-                                                   "^::strpbrk$;"
-                                                   "^::strrchr$;"
-                                                   "^::strstr$;"
-                                                   "^::strtod$;"
-                                                   "^::strtof$;"
-                                                   "^::strtoimax$;"
-                                                   "^::strtok$;"
-                                                   "^::strtok_s$;"
-                                                   "^::strtol$;"
-                                                   "^::strtold$;"
-                                                   "^::strtoll$;"
-                                                   "^::strtoul$;"
-                                                   "^::strtoull$;"
-                                                   "^::strtoumax$;"
-                                                   "^::strxfrm$;"
-                                                   "^::swprintf$;"
-                                                   "^::swprintf_s$;"
-                                                   "^::swscanf$;"
-                                                   "^::swscanf_s$;"
-                                                   "^::thrd_create$;"
-                                                   "^::thrd_detach$;"
-                                                   "^::thrd_join$;"
-                                                   "^::thrd_sleep$;"
-                                                   "^::time$;"
-                                                   "^::timespec_get$;"
-                                                   "^::tmpfile$;"
-                                                   "^::tmpfile_s$;"
-                                                   "^::tmpnam$;"
-                                                   "^::tmpnam_s$;"
-                                                   "^::tss_create$;"
-                                                   "^::tss_get$;"
-                                                   "^::tss_set$;"
-                                                   "^::ungetc$;"
-                                                   "^::ungetwc$;"
-                                                   "^::vfprintf$;"
-                                                   "^::vfprintf_s$;"
-                                                   "^::vfscanf$;"
-                                                   "^::vfscanf_s$;"
-                                                   "^::vfwprintf$;"
-                                                   "^::vfwprintf_s$;"
-                                                   "^::vfwscanf$;"
-                                                   "^::vfwscanf_s$;"
-                                                   "^::vprintf_s$;"
-                                                   "^::vscanf$;"
-                                                   "^::vscanf_s$;"
-                                                   "^::vsnprintf$;"
-                                                   "^::vsnprintf_s$;"
-                                                   "^::vsprintf$;"
-                                                   "^::vsprintf_s$;"
-                                                   "^::vsscanf$;"
-                                                   "^::vsscanf_s$;"
-                                                   "^::vswprintf$;"
-                                                   "^::vswprintf_s$;"
-                                                   "^::vswscanf$;"
-                                                   "^::vswscanf_s$;"
-                                                   "^::vwprintf_s$;"
-                                                   "^::vwscanf$;"
-                                                   "^::vwscanf_s$;"
-                                                   "^::wcrtomb$;"
-                                                   "^::wcschr$;"
-                                                   "^::wcsftime$;"
-                                                   "^::wcspbrk$;"
-                                                   "^::wcsrchr$;"
-                                                   "^::wcsrtombs$;"
-                                                   "^::wcsrtombs_s$;"
-                                                   "^::wcsstr$;"
-                                                   "^::wcstod$;"
-                                                   "^::wcstof$;"
-                                                   "^::wcstoimax$;"
-                                                   "^::wcstok$;"
-                                                   "^::wcstok_s$;"
-                                                   "^::wcstol$;"
-                                                   "^::wcstold$;"
-                                                   "^::wcstoll$;"
-                                                   "^::wcstombs$;"
-                                                   "^::wcstombs_s$;"
-                                                   "^::wcstoul$;"
-                                                   "^::wcstoull$;"
-                                                   "^::wcstoumax$;"
-                                                   "^::wcsxfrm$;"
-                                                   "^::wctob$;"
-                                                   "^::wctrans$;"
-                                                   "^::wctype$;"
-                                                   "^::wmemchr$;"
-                                                   "^::wprintf_s$;"
-                                                   "^::wscanf$;"
-                                                   "^::wscanf_s$;";
+static constexpr StringRef CertErr33CCheckedFunctions = "^::aligned_alloc$;"
+                                                        "^::asctime_s$;"
+                                                        "^::at_quick_exit$;"
+                                                        "^::atexit$;"
+                                                        "^::bsearch$;"
+                                                        "^::bsearch_s$;"
+                                                        "^::btowc$;"
+                                                        "^::c16rtomb$;"
+                                                        "^::c32rtomb$;"
+                                                        "^::calloc$;"
+                                                        "^::clock$;"
+                                                        "^::cnd_broadcast$;"
+                                                        "^::cnd_init$;"
+                                                        "^::cnd_signal$;"
+                                                        "^::cnd_timedwait$;"
+                                                        "^::cnd_wait$;"
+                                                        "^::ctime_s$;"
+                                                        "^::fclose$;"
+                                                        "^::fflush$;"
+                                                        "^::fgetc$;"
+                                                        "^::fgetpos$;"
+                                                        "^::fgets$;"
+                                                        "^::fgetwc$;"
+                                                        "^::fopen$;"
+                                                        "^::fopen_s$;"
+                                                        "^::fprintf$;"
+                                                        "^::fprintf_s$;"
+                                                        "^::fputc$;"
+                                                        "^::fputs$;"
+                                                        "^::fputwc$;"
+                                                        "^::fputws$;"
+                                                        "^::fread$;"
+                                                        "^::freopen$;"
+                                                        "^::freopen_s$;"
+                                                        "^::fscanf$;"
+                                                        "^::fscanf_s$;"
+                                                        "^::fseek$;"
+                                                        "^::fsetpos$;"
+                                                        "^::ftell$;"
+                                                        "^::fwprintf$;"
+                                                        "^::fwprintf_s$;"
+                                                        "^::fwrite$;"
+                                                        "^::fwscanf$;"
+                                                        "^::fwscanf_s$;"
+                                                        "^::getc$;"
+                                                        "^::getchar$;"
+                                                        "^::getenv$;"
+                                                        "^::getenv_s$;"
+                                                        "^::gets_s$;"
+                                                        "^::getwc$;"
+                                                        "^::getwchar$;"
+                                                        "^::gmtime$;"
+                                                        "^::gmtime_s$;"
+                                                        "^::localtime$;"
+                                                        "^::localtime_s$;"
+                                                        "^::malloc$;"
+                                                        "^::mbrtoc16$;"
+                                                        "^::mbrtoc32$;"
+                                                        "^::mbsrtowcs$;"
+                                                        "^::mbsrtowcs_s$;"
+                                                        "^::mbstowcs$;"
+                                                        "^::mbstowcs_s$;"
+                                                        "^::memchr$;"
+                                                        "^::mktime$;"
+                                                        "^::mtx_init$;"
+                                                        "^::mtx_lock$;"
+                                                        "^::mtx_timedlock$;"
+                                                        "^::mtx_trylock$;"
+                                                        "^::mtx_unlock$;"
+                                                        "^::printf_s$;"
+                                                        "^::putc$;"
+                                                        "^::putwc$;"
+                                                        "^::raise$;"
+                                                        "^::realloc$;"
+                                                        "^::remove$;"
+                                                        "^::rename$;"
+                                                        "^::scanf$;"
+                                                        "^::scanf_s$;"
+                                                        "^::setlocale$;"
+                                                        "^::setvbuf$;"
+                                                        "^::signal$;"
+                                                        "^::snprintf$;"
+                                                        "^::snprintf_s$;"
+                                                        "^::sprintf$;"
+                                                        "^::sprintf_s$;"
+                                                        "^::sscanf$;"
+                                                        "^::sscanf_s$;"
+                                                        "^::strchr$;"
+                                                        "^::strerror_s$;"
+                                                        "^::strftime$;"
+                                                        "^::strpbrk$;"
+                                                        "^::strrchr$;"
+                                                        "^::strstr$;"
+                                                        "^::strtod$;"
+                                                        "^::strtof$;"
+                                                        "^::strtoimax$;"
+                                                        "^::strtok$;"
+                                                        "^::strtok_s$;"
+                                                        "^::strtol$;"
+                                                        "^::strtold$;"
+                                                        "^::strtoll$;"
+                                                        "^::strtoul$;"
+                                                        "^::strtoull$;"
+                                                        "^::strtoumax$;"
+                                                        "^::strxfrm$;"
+                                                        "^::swprintf$;"
+                                                        "^::swprintf_s$;"
+                                                        "^::swscanf$;"
+                                                        "^::swscanf_s$;"
+                                                        "^::thrd_create$;"
+                                                        "^::thrd_detach$;"
+                                                        "^::thrd_join$;"
+                                                        "^::thrd_sleep$;"
+                                                        "^::time$;"
+                                                        "^::timespec_get$;"
+                                                        "^::tmpfile$;"
+                                                        "^::tmpfile_s$;"
+                                                        "^::tmpnam$;"
+                                                        "^::tmpnam_s$;"
+                                                        "^::tss_create$;"
+                                                        "^::tss_get$;"
+                                                        "^::tss_set$;"
+                                                        "^::ungetc$;"
+                                                        "^::ungetwc$;"
+                                                        "^::vfprintf$;"
+                                                        "^::vfprintf_s$;"
+                                                        "^::vfscanf$;"
+                                                        "^::vfscanf_s$;"
+                                                        "^::vfwprintf$;"
+                                                        "^::vfwprintf_s$;"
+                                                        "^::vfwscanf$;"
+                                                        "^::vfwscanf_s$;"
+                                                        "^::vprintf_s$;"
+                                                        "^::vscanf$;"
+                                                        "^::vscanf_s$;"
+                                                        "^::vsnprintf$;"
+                                                        "^::vsnprintf_s$;"
+                                                        "^::vsprintf$;"
+                                                        "^::vsprintf_s$;"
+                                                        "^::vsscanf$;"
+                                                        "^::vsscanf_s$;"
+                                                        "^::vswprintf$;"
+                                                        "^::vswprintf_s$;"
+                                                        "^::vswscanf$;"
+                                                        "^::vswscanf_s$;"
+                                                        "^::vwprintf_s$;"
+                                                        "^::vwscanf$;"
+                                                        "^::vwscanf_s$;"
+                                                        "^::wcrtomb$;"
+                                                        "^::wcschr$;"
+                                                        "^::wcsftime$;"
+                                                        "^::wcspbrk$;"
+                                                        "^::wcsrchr$;"
+                                                        "^::wcsrtombs$;"
+                                                        "^::wcsrtombs_s$;"
+                                                        "^::wcsstr$;"
+                                                        "^::wcstod$;"
+                                                        "^::wcstof$;"
+                                                        "^::wcstoimax$;"
+                                                        "^::wcstok$;"
+                                                        "^::wcstok_s$;"
+                                                        "^::wcstol$;"
+                                                        "^::wcstold$;"
+                                                        "^::wcstoll$;"
+                                                        "^::wcstombs$;"
+                                                        "^::wcstombs_s$;"
+                                                        "^::wcstoul$;"
+                                                        "^::wcstoull$;"
+                                                        "^::wcstoumax$;"
+                                                        "^::wcsxfrm$;"
+                                                        "^::wctob$;"
+                                                        "^::wctrans$;"
+                                                        "^::wctype$;"
+                                                        "^::wmemchr$;"
+                                                        "^::wprintf_s$;"
+                                                        "^::wscanf$;"
+                                                        "^::wscanf_s$;";
 
-} // namespace
-
-namespace clang::tidy {
 namespace cert {
 namespace {
 
diff --git a/clang-tools-extra/clang-tidy/concurrency/MtUnsafeCheck.cpp b/clang-tools-extra/clang-tidy/concurrency/MtUnsafeCheck.cpp
index f8050bcfe3263..1a14f7219d324 100644
--- a/clang-tools-extra/clang-tidy/concurrency/MtUnsafeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/concurrency/MtUnsafeCheck.cpp
@@ -11,8 +11,10 @@
 
 using namespace clang::ast_matchers;
 
+namespace clang::tidy {
+
 // Initial list was extracted from gcc documentation
-static const clang::StringRef GlibcFunctions[] = {
+static constexpr StringRef GlibcFunctions[] = {
     "::argp_error",
     "::argp_help",
     "::argp_parse",
@@ -171,7 +173,7 @@ static const clang::StringRef GlibcFunctions[] = {
     "::wordexp",
 };
 
-static const clang::StringRef PosixFunctions[] = {
+static constexpr StringRef PosixFunctions[] = {
     "::asctime",
     "::basename",
     "::catgets",
@@ -256,8 +258,6 @@ static const clang::StringRef PosixFunctions[] = {
     "::wctomb",
 };
 
-namespace clang::tidy {
-
 template <> struct OptionEnumMapping<concurrency::MtUnsafeCheck::FunctionSet> {
   static llvm::ArrayRef<
       std::pair<concurrency::MtUnsafeCheck::FunctionSet, StringRef>>
@@ -273,7 +273,7 @@ template <> struct OptionEnumMapping<concurrency::MtUnsafeCheck::FunctionSet> {
 
 namespace concurrency {
 
-static ast_matchers::internal::Matcher<clang::NamedDecl>
+static ast_matchers::internal::Matcher<NamedDecl>
 hasAnyMtUnsafeNames(MtUnsafeCheck::FunctionSet Libc) {
   switch (Libc) {
   case MtUnsafeCheck::FunctionSet::Posix:
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
index e1636e40507ea..a8f2dcc8f5e1b 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
@@ -48,7 +48,7 @@ static std::string createReplacementText(const LambdaExpr *Lambda) {
   std::string Replacement;
   llvm::raw_string_ostream Stream(Replacement);
 
-  auto AppendName = [&](llvm::StringRef Name) {
+  auto AppendName = [&](StringRef Name) {
     if (!Replacement.empty())
       Stream << ", ";
     if (Lambda->getCaptureDefault() == LCD_ByRef && Name != "this")
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/NoSuspendWithLockCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/NoSuspendWithLockCheck.cpp
index ee3a45c171e32..f2460aec3b2fd 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/NoSuspendWithLockCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/NoSuspendWithLockCheck.cpp
@@ -56,7 +56,7 @@ void NoSuspendWithLockCheck::check(const MatchFinder::MatchResult &Result) {
   Options.AddTemporaryDtors = true;
 
   const std::unique_ptr<CFG> TheCFG = CFG::buildCFG(
-      nullptr, const_cast<clang::CompoundStmt *>(Block), &Context, Options);
+      nullptr, const_cast<CompoundStmt *>(Block), &Context, Options);
   if (!TheCFG)
     return;
 
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp
index 164943293c8d2..f04b5e87a084c 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp
@@ -251,12 +251,12 @@ void PreferMemberInitializerCheck::check(
           // comma.
           InsertPrefix = ", ";
         } else {
-          InsertPos = Lexer::getLocForEndOfToken(
-              Ctor->getTypeSourceInfo()
-                  ->getTypeLoc()
-                  .getAs<clang::FunctionTypeLoc>()
-                  .getLocalRangeEnd(),
-              0, *Result.SourceManager, getLangOpts());
+          InsertPos = Lexer::getLocForEndOfToken(Ctor->getTypeSourceInfo()
+                                                     ->getTypeLoc()
+                                                     .getAs<FunctionTypeLoc>()
+                                                     .getLocalRangeEnd(),
+                                                 0, *Result.SourceManager,
+                                                 getLangOpts());
 
           // If this is first time in the loop, there are no initializers so
           // `:` declares member initialization list. If this is a
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.cpp
index 73f43d3cd3b1a..a98dabbb14f5f 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.cpp
@@ -16,7 +16,7 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
-static constexpr llvm::StringRef DefaultExclusionStr =
+static constexpr StringRef DefaultExclusionStr =
     "::std::map;::std::unordered_map;::std::flat_map";
 
 ProBoundsAvoidUncheckedContainerAccessCheck::
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.h
index 85b5a93940562..68d4c83ef6191 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.h
@@ -35,11 +35,11 @@ class ProBoundsAvoidUncheckedContainerAccessCheck : public ClangTidyCheck {
 
 private:
   // A list of class names that are excluded from the warning
-  std::vector<llvm::StringRef> ExcludedClasses;
+  std::vector<StringRef> ExcludedClasses;
   // Setting which fix to suggest
   FixModes FixMode;
-  llvm::StringRef FixFunction;
-  llvm::StringRef FixFunctionEmptyArgs;
+  StringRef FixFunction;
+  StringRef FixFunctionEmptyArgs;
 };
 } // namespace clang::tidy::cppcoreguidelines
 
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.cpp
index a8ef59157958f..1ef64b702cd66 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.cpp
@@ -76,7 +76,7 @@ void SpecialMemberFunctionsCheck::registerMatchers(MatchFinder *Finder) {
       this);
 }
 
-static llvm::StringRef
+static StringRef
 toString(SpecialMemberFunctionsCheck::SpecialMemberFunctionKind K) {
   switch (K) {
   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::Destructor:
@@ -101,7 +101,7 @@ toString(SpecialMemberFunctionsCheck::SpecialMemberFunctionKind K) {
 
 static std::string
 join(ArrayRef<SpecialMemberFunctionsCheck::SpecialMemberFunctionKind> SMFS,
-     llvm::StringRef AndOr) {
+     StringRef AndOr) {
   assert(!SMFS.empty() &&
          "List of defined or undefined members should never be empty.");
   std::string Buffer;
@@ -126,7 +126,7 @@ void SpecialMemberFunctionsCheck::check(
                 std::string(MatchedDecl->getName()));
 
   auto StoreMember = [this, &ID](SpecialMemberFunctionData Data) {
-    llvm::SmallVectorImpl<SpecialMemberFunctionData> &Members =
+    SmallVectorImpl<SpecialMemberFunctionData> &Members =
         ClassWithSpecialMembers[ID];
     if (!llvm::is_contained(Members, Data))
       Members.push_back(std::move(Data));
@@ -165,7 +165,7 @@ void SpecialMemberFunctionsCheck::onEndOfTranslationUnit() {
 void SpecialMemberFunctionsCheck::checkForMissingMembers(
     const ClassDefId &ID,
     llvm::ArrayRef<SpecialMemberFunctionData> DefinedMembers) {
-  llvm::SmallVector<SpecialMemberFunctionKind, 5> MissingMembers;
+  SmallVector<SpecialMemberFunctionKind, 5> MissingMembers;
 
   auto HasMember = [&](SpecialMemberFunctionKind Kind) {
     return llvm::any_of(DefinedMembers, [Kind](const auto &Data) {
@@ -234,7 +234,7 @@ void SpecialMemberFunctionsCheck::checkForMissingMembers(
   }
 
   if (!MissingMembers.empty()) {
-    llvm::SmallVector<SpecialMemberFunctionKind, 5> DefinedMemberKinds;
+    SmallVector<SpecialMemberFunctionKind, 5> DefinedMemberKinds;
     for (const auto &Data : DefinedMembers)
       if (!Data.IsImplicit)
         DefinedMemberKinds.push_back(Data.FunctionKind);
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.h
index 6d76e07078f3b..ecf43468eea20 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.h
@@ -56,8 +56,7 @@ class SpecialMemberFunctionsCheck : public ClangTidyCheck {
   using ClassDefId = std::pair<SourceLocation, std::string>;
 
   using ClassDefiningSpecialMembersMap =
-      llvm::DenseMap<ClassDefId,
-                     llvm::SmallVector<SpecialMemberFunctionData, 5>>;
+      llvm::DenseMap<ClassDefId, SmallVector<SpecialMemberFunctionData, 5>>;
 
 private:
   void checkForMissingMembers(
diff --git a/clang-tools-extra/clang-tidy/custom/CustomTidyModule.cpp b/clang-tools-extra/clang-tidy/custom/CustomTidyModule.cpp
index f2267c2549eac..c68d186eefd7d 100644
--- a/clang-tools-extra/clang-tidy/custom/CustomTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/custom/CustomTidyModule.cpp
@@ -15,17 +15,17 @@ namespace custom {
 // will changed dynamically when switching to different source file.
 static void registerCustomChecks(const ClangTidyOptions &Options,
                                  ClangTidyCheckFactories &Factories) {
-  static llvm::SmallSet<llvm::SmallString<32>, 8> CustomCheckNames{};
+  static llvm::SmallSet<SmallString<32>, 8> CustomCheckNames{};
   if (!Options.CustomChecks.has_value() || Options.CustomChecks->empty())
     return;
-  for (const llvm::SmallString<32> &Name : CustomCheckNames)
+  for (const SmallString<32> &Name : CustomCheckNames)
     Factories.eraseCheck(Name);
   for (const ClangTidyOptions::CustomCheckValue &V :
        Options.CustomChecks.value()) {
-    llvm::SmallString<32> Name = llvm::StringRef{"custom-" + V.Name};
+    SmallString<32> Name = StringRef{"custom-" + V.Name};
     Factories.registerCheckFactory(
         // add custom- prefix to avoid conflicts with builtin checks
-        Name, [&V](llvm::StringRef Name, ClangTidyContext *Context) {
+        Name, [&V](StringRef Name, ClangTidyContext *Context) {
           return std::make_unique<custom::QueryCheck>(Name, V, Context);
         });
     CustomCheckNames.insert(std::move(Name));
diff --git a/clang-tools-extra/clang-tidy/custom/QueryCheck.cpp b/clang-tools-extra/clang-tidy/custom/QueryCheck.cpp
index 315ce5840e5d4..60f2f91708c7b 100644
--- a/clang-tools-extra/clang-tidy/custom/QueryCheck.cpp
+++ b/clang-tools-extra/clang-tidy/custom/QueryCheck.cpp
@@ -31,27 +31,27 @@ parseQuery(const ClangTidyOptions::CustomCheckValue &V,
            ClangTidyContext *Context) {
   SmallVector<ast_matchers::dynamic::DynTypedMatcher> Matchers{};
   clang::query::QuerySession QS({});
-  llvm::StringRef QueryStringRef{V.Query};
+  StringRef QueryStringRef{V.Query};
   while (!QueryStringRef.empty()) {
     const query::QueryRef Q = query::QueryParser::parse(QueryStringRef, QS);
     switch (Q->Kind) {
     case query::QK_Match: {
-      const auto &MatchQuery = llvm::cast<query::MatchQuery>(*Q);
+      const auto &MatchQuery = cast<query::MatchQuery>(*Q);
       Matchers.push_back(MatchQuery.Matcher);
       break;
     }
     case query::QK_Let: {
-      const auto &LetQuery = llvm::cast<query::LetQuery>(*Q);
+      const auto &LetQuery = cast<query::LetQuery>(*Q);
       LetQuery.run(llvm::errs(), QS);
       break;
     }
     case query::QK_NoOp: {
-      const auto &NoOpQuery = llvm::cast<query::NoOpQuery>(*Q);
+      const auto &NoOpQuery = cast<query::NoOpQuery>(*Q);
       NoOpQuery.run(llvm::errs(), QS);
       break;
     }
     case query::QK_Invalid: {
-      const auto &InvalidQuery = llvm::cast<query::InvalidQuery>(*Q);
+      const auto &InvalidQuery = cast<query::InvalidQuery>(*Q);
       emitConfigurationDiag(Context, InvalidQuery.ErrStr, V.Name);
       return {};
     }
@@ -99,7 +99,7 @@ parseQuery(const ClangTidyOptions::CustomCheckValue &V,
   return Matchers;
 }
 
-QueryCheck::QueryCheck(llvm::StringRef Name,
+QueryCheck::QueryCheck(StringRef Name,
                        const ClangTidyOptions::CustomCheckValue &V,
                        ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context) {
@@ -107,11 +107,11 @@ QueryCheck::QueryCheck(llvm::StringRef Name,
     auto DiagnosticIdIt =
         Diags
             .try_emplace(D.Level.value_or(DiagnosticIDs::Warning),
-                         llvm::StringMap<llvm::SmallVector<std::string>>{})
+                         llvm::StringMap<SmallVector<std::string>>{})
             .first;
     auto DiagMessageIt =
         DiagnosticIdIt->getSecond()
-            .try_emplace(D.BindName, llvm::SmallVector<std::string>{})
+            .try_emplace(D.BindName, SmallVector<std::string>{})
             .first;
     DiagMessageIt->second.emplace_back(D.Message);
   }
diff --git a/clang-tools-extra/clang-tidy/custom/QueryCheck.h b/clang-tools-extra/clang-tidy/custom/QueryCheck.h
index 3dcdc518736c2..15ca8e0884f7d 100644
--- a/clang-tools-extra/clang-tidy/custom/QueryCheck.h
+++ b/clang-tools-extra/clang-tidy/custom/QueryCheck.h
@@ -22,15 +22,14 @@ namespace clang::tidy::custom {
 /// Not directly visible to users.
 class QueryCheck : public ClangTidyCheck {
 public:
-  QueryCheck(llvm::StringRef Name, const ClangTidyOptions::CustomCheckValue &V,
+  QueryCheck(StringRef Name, const ClangTidyOptions::CustomCheckValue &V,
              ClangTidyContext *Context);
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  llvm::SmallVector<ast_matchers::dynamic::DynTypedMatcher> Matchers;
-  using BindNameMapToDiagMessage =
-      llvm::StringMap<llvm::SmallVector<std::string>>;
+  SmallVector<ast_matchers::dynamic::DynTypedMatcher> Matchers;
+  using BindNameMapToDiagMessage = llvm::StringMap<SmallVector<std::string>>;
   using DiagMaps =
       llvm::DenseMap<DiagnosticIDs::Level, BindNameMapToDiagMessage>;
   DiagMaps Diags;
diff --git a/clang-tools-extra/clang-tidy/google/FunctionNamingCheck.cpp b/clang-tools-extra/clang-tidy/google/FunctionNamingCheck.cpp
index 459cc1bbe9b48..e0b4ba5351b02 100644
--- a/clang-tools-extra/clang-tidy/google/FunctionNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/FunctionNamingCheck.cpp
@@ -75,7 +75,7 @@ static FixItHint generateFixItHint(const FunctionDecl *Decl) {
   if (NewName != Name)
     return FixItHint::CreateReplacement(
         CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
-        llvm::StringRef(NewName));
+        StringRef(NewName));
 
   return {};
 }
diff --git a/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp
index 7470b1eb206bb..ec4fe724fcf58 100644
--- a/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp
@@ -46,13 +46,12 @@ static FixItHint generateFixItHint(const VarDecl *Decl, bool IsConst) {
     return {};
   }
 
-  auto NewName = (IsConst ? "k" : "g") +
-                 llvm::StringRef(std::string(1, FC)).upper() +
+  auto NewName = (IsConst ? "k" : "g") + StringRef(std::string(1, FC)).upper() +
                  Decl->getName().substr(1).str();
 
   return FixItHint::CreateReplacement(
       CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
-      llvm::StringRef(NewName));
+      StringRef(NewName));
 }
 
 void GlobalVariableDeclarationCheck::registerMatchers(MatchFinder *Finder) {
diff --git a/clang-tools-extra/clang-tidy/google/TodoCommentCheck.cpp b/clang-tools-extra/clang-tidy/google/TodoCommentCheck.cpp
index f6a6811af006f..006430cbc7522 100644
--- a/clang-tools-extra/clang-tidy/google/TodoCommentCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/TodoCommentCheck.cpp
@@ -41,8 +41,7 @@ class TodoCommentCheck::TodoCommentHandler : public CommentHandler {
   TodoCommentHandler(TodoCommentCheck &Check, std::optional<std::string> User)
       : Check(Check), User(User ? *User : "unknown"),
         TodoMatch(R"(^// *TODO *((\((.*)\))?:?( )?|: *(.*) *- *)?(.*)$)") {
-    const llvm::StringRef TodoStyleString =
-        Check.Options.get("Style", "Hyphen");
+    const StringRef TodoStyleString = Check.Options.get("Style", "Hyphen");
     for (const auto &[Value, Name] :
          OptionEnumMapping<StyleKind>::getEnumMapping()) {
       if (Name == TodoStyleString) {
diff --git a/clang-tools-extra/clang-tidy/google/UpgradeGoogletestCaseCheck.cpp b/clang-tools-extra/clang-tidy/google/UpgradeGoogletestCaseCheck.cpp
index 9ca23aaeb6211..a5124ad784a2f 100644
--- a/clang-tools-extra/clang-tidy/google/UpgradeGoogletestCaseCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/UpgradeGoogletestCaseCheck.cpp
@@ -17,13 +17,12 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::google {
 
-static const llvm::StringRef RenameCaseToSuiteMessage =
+static constexpr StringRef RenameCaseToSuiteMessage =
     "Google Test APIs named with 'case' are deprecated; use equivalent APIs "
     "named with 'suite'";
 
-static std::optional<llvm::StringRef>
-getNewMacroName(llvm::StringRef MacroName) {
-  static const llvm::StringMap<llvm::StringRef> ReplacementMap = {
+static std::optional<StringRef> getNewMacroName(StringRef MacroName) {
+  static const llvm::StringMap<StringRef> ReplacementMap = {
       {"TYPED_TEST_CASE", "TYPED_TEST_SUITE"},
       {"TYPED_TEST_CASE_P", "TYPED_TEST_SUITE_P"},
       {"REGISTER_TYPED_TEST_CASE_P", "REGISTER_TYPED_TEST_SUITE_P"},
@@ -62,7 +61,7 @@ class UpgradeGoogletestCasePPCallback : public PPCallbacks {
       // We check if the newly defined macro is one of the target replacements.
       // This ensures that the check creates warnings only if it is including a
       // recent enough version of Google Test.
-      const llvm::StringRef FileName = PP->getSourceManager().getFilename(
+      const StringRef FileName = PP->getSourceManager().getFilename(
           MD->getMacroInfo()->getDefinitionLoc());
       ReplacementFound = FileName.ends_with("gtest/gtest-typed-test.h") &&
                          PP->getSpelling(MacroNameTok) == "TYPED_TEST_SUITE";
@@ -87,18 +86,18 @@ class UpgradeGoogletestCasePPCallback : public PPCallbacks {
 private:
   enum class CheckAction { Warn, Rename };
 
-  void macroUsed(const clang::Token &MacroNameTok, const MacroDefinition &MD,
+  void macroUsed(const Token &MacroNameTok, const MacroDefinition &MD,
                  SourceLocation Loc, CheckAction Action) {
     if (!ReplacementFound)
       return;
 
     const std::string Name = PP->getSpelling(MacroNameTok);
 
-    std::optional<llvm::StringRef> Replacement = getNewMacroName(Name);
+    std::optional<StringRef> Replacement = getNewMacroName(Name);
     if (!Replacement)
       return;
 
-    const llvm::StringRef FileName = PP->getSourceManager().getFilename(
+    const StringRef FileName = PP->getSourceManager().getFilename(
         MD.getMacroInfo()->getDefinitionLoc());
     if (!FileName.ends_with("gtest/gtest-typed-test.h"))
       return;
@@ -201,8 +200,8 @@ void UpgradeGoogletestCaseCheck::registerMatchers(MatchFinder *Finder) {
       this);
 }
 
-static llvm::StringRef getNewMethodName(llvm::StringRef CurrentName) {
-  static const llvm::StringMap<llvm::StringRef> ReplacementMap = {
+static StringRef getNewMethodName(StringRef CurrentName) {
+  static const llvm::StringMap<StringRef> ReplacementMap = {
       {"SetUpTestCase", "SetUpTestSuite"},
       {"TearDownTestCase", "TearDownTestSuite"},
       {"test_case_name", "test_suite_name"},
@@ -238,7 +237,7 @@ static bool isInTemplate(const NodeType &Node,
 
 static bool
 derivedTypeHasReplacementMethod(const MatchFinder::MatchResult &Result,
-                                llvm::StringRef ReplacementMethod) {
+                                StringRef ReplacementMethod) {
   const auto *Class = Result.Nodes.getNodeAs<CXXRecordDecl>("class");
   return !match(cxxRecordDecl(
                     unless(isExpansionInFileMatching(
@@ -264,7 +263,7 @@ getAliasNameRange(const MatchFinder::MatchResult &Result) {
 }
 
 void UpgradeGoogletestCaseCheck::check(const MatchFinder::MatchResult &Result) {
-  llvm::StringRef ReplacementText;
+  StringRef ReplacementText;
   CharSourceRange ReplacementRange;
   if (const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method")) {
     ReplacementText = getNewMethodName(Method->getName());
@@ -273,7 +272,7 @@ void UpgradeGoogletestCaseCheck::check(const MatchFinder::MatchResult &Result) {
     bool IsInTemplate = false;
     bool AddFix = true;
     if (const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("call")) {
-      const auto *Callee = llvm::cast<MemberExpr>(Call->getCallee());
+      const auto *Callee = cast<MemberExpr>(Call->getCallee());
       ReplacementRange = CharSourceRange::getTokenRange(Callee->getMemberLoc(),
                                                         Callee->getMemberLoc());
       IsInInstantiation = isInInstantiation(*Call, Result);
diff --git a/clang-tools-extra/clang-tidy/hicpp/IgnoredRemoveResultCheck.cpp b/clang-tools-extra/clang-tidy/hicpp/IgnoredRemoveResultCheck.cpp
index 5321fd8d5b1c2..35a10fcf91105 100644
--- a/clang-tools-extra/clang-tidy/hicpp/IgnoredRemoveResultCheck.cpp
+++ b/clang-tools-extra/clang-tidy/hicpp/IgnoredRemoveResultCheck.cpp
@@ -10,7 +10,7 @@
 
 namespace clang::tidy::hicpp {
 
-IgnoredRemoveResultCheck::IgnoredRemoveResultCheck(llvm::StringRef Name,
+IgnoredRemoveResultCheck::IgnoredRemoveResultCheck(StringRef Name,
                                                    ClangTidyContext *Context)
     : UnusedReturnValueCheck(Name, Context,
                              {
diff --git a/clang-tools-extra/clang-tidy/llvm/UseNewMLIROpBuilderCheck.cpp b/clang-tools-extra/clang-tidy/llvm/UseNewMLIROpBuilderCheck.cpp
index e4564149066bd..ca3e778e573c1 100644
--- a/clang-tools-extra/clang-tidy/llvm/UseNewMLIROpBuilderCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvm/UseNewMLIROpBuilderCheck.cpp
@@ -50,14 +50,14 @@ static EditGenerator rewrite(RangeSelector Call, RangeSelector Builder) {
     auto NextToken = [&](std::optional<Token> CurrentToken) {
       if (!CurrentToken)
         return CurrentToken;
-      if (CurrentToken->is(clang::tok::eof))
+      if (CurrentToken->is(tok::eof))
         return std::optional<Token>();
       return utils::lexer::findNextTokenSkippingComments(
           CurrentToken->getLocation(), SM, LangOpts);
     };
     std::optional<Token> LessToken =
         utils::lexer::findNextTokenSkippingComments(Begin, SM, LangOpts);
-    while (LessToken && LessToken->getKind() != clang::tok::less)
+    while (LessToken && LessToken->getKind() != tok::less)
       LessToken = NextToken(LessToken);
     if (!LessToken) {
       return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
@@ -66,7 +66,7 @@ static EditGenerator rewrite(RangeSelector Call, RangeSelector Builder) {
 
     std::optional<Token> EndToken = NextToken(LessToken);
     std::optional<Token> GreaterToken = NextToken(EndToken);
-    for (; GreaterToken && GreaterToken->getKind() != clang::tok::greater;
+    for (; GreaterToken && GreaterToken->getKind() != tok::greater;
          GreaterToken = NextToken(GreaterToken)) {
       EndToken = GreaterToken;
     }
@@ -76,7 +76,7 @@ static EditGenerator rewrite(RangeSelector Call, RangeSelector Builder) {
     }
 
     std::optional<Token> ArgStart = NextToken(GreaterToken);
-    if (!ArgStart || ArgStart->getKind() != clang::tok::l_paren) {
+    if (!ArgStart || ArgStart->getKind() != tok::l_paren) {
       return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
                                                  "missing '(' token");
     }
@@ -85,7 +85,7 @@ static EditGenerator rewrite(RangeSelector Call, RangeSelector Builder) {
       return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
                                                  "unexpected end of file");
     }
-    const bool HasArgs = Arg->getKind() != clang::tok::r_paren;
+    const bool HasArgs = Arg->getKind() != tok::r_paren;
 
     Expected<CharSourceRange> BuilderRange = Builder(Result);
     if (!BuilderRange)
@@ -93,7 +93,7 @@ static EditGenerator rewrite(RangeSelector Call, RangeSelector Builder) {
 
     // Helper for concatting below.
     auto GetText = [&](const CharSourceRange &Range) {
-      return clang::Lexer::getSourceText(Range, SM, LangOpts);
+      return Lexer::getSourceText(Range, SM, LangOpts);
     };
 
     Edit Replace;
diff --git a/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp b/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
index dd1ef076c65e1..8f3d150ce0117 100644
--- a/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
@@ -64,7 +64,7 @@ void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
       << FuncDecl << RequiredNamespaceRefMacroName;
 
   diag(FuncDecl->getLocation(), "resolves to this declaration",
-       clang::DiagnosticIDs::Note);
+       DiagnosticIDs::Note);
 }
 
 } // namespace clang::tidy::llvm_libc
diff --git a/clang-tools-extra/clang-tidy/llvmlibc/InlineFunctionDeclCheck.cpp b/clang-tools-extra/clang-tidy/llvmlibc/InlineFunctionDeclCheck.cpp
index 9f09947c4da29..9eb749dede6d2 100644
--- a/clang-tools-extra/clang-tidy/llvmlibc/InlineFunctionDeclCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvmlibc/InlineFunctionDeclCheck.cpp
@@ -78,8 +78,7 @@ void InlineFunctionDeclCheck::check(const MatchFinder::MatchResult &Result) {
   // Check if decl starts with LIBC_INLINE
   auto Loc = FullSourceLoc(Result.SourceManager->getFileLoc(SrcBegin),
                            *Result.SourceManager);
-  const llvm::StringRef SrcText =
-      Loc.getBufferData().drop_front(Loc.getFileOffset());
+  const StringRef SrcText = Loc.getBufferData().drop_front(Loc.getFileOffset());
   if (SrcText.starts_with("LIBC_INLINE"))
     return;
 
diff --git a/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp b/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
index cef2c0ebb94f0..f386bd613dfc6 100644
--- a/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
@@ -45,7 +45,7 @@ ConfusableIdentifierCheck::~ConfusableIdentifierCheck() = default;
 // We're skipping 1. and 3. for the sake of simplicity, but this can lead to
 // false positive.
 
-static llvm::SmallString<64U> skeleton(StringRef Name) {
+static SmallString<64U> skeleton(StringRef Name) {
   using namespace llvm;
   SmallString<64U> Skeleton;
   Skeleton.reserve(1U + Name.size());
@@ -102,7 +102,7 @@ struct Entry {
 // that has no corresponding context, such as an alias template or variable
 // template.
 using DeclsWithinContextMap =
-    llvm::DenseMap<const Decl *, llvm::SmallVector<Entry, 1>>;
+    llvm::DenseMap<const Decl *, SmallVector<Entry, 1>>;
 
 static bool addToContext(DeclsWithinContextMap &DeclsWithinContext,
                          const Decl *Context, Entry E) {
@@ -189,7 +189,7 @@ void ConfusableIdentifierCheck::addDeclToCheck(const NamedDecl *ND,
 }
 
 void ConfusableIdentifierCheck::onEndOfTranslationUnit() {
-  llvm::StringMap<llvm::SmallVector<const IdentifierInfo *, 1>> SkeletonToNames;
+  llvm::StringMap<SmallVector<const IdentifierInfo *, 1>> SkeletonToNames;
   // Compute the skeleton for each identifier.
   for (auto &[Ident, Decls] : NameToDecls)
     SkeletonToNames[skeleton(Ident->getName())].push_back(Ident);
diff --git a/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.h b/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.h
index 5b98d48780eb5..e88bfc9025536 100644
--- a/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.h
@@ -33,9 +33,8 @@ class ConfusableIdentifierCheck : public ClangTidyCheck {
 private:
   void addDeclToCheck(const NamedDecl *ND, const Decl *Parent);
 
-  llvm::DenseMap<
-      const IdentifierInfo *,
-      llvm::SmallVector<std::pair<const NamedDecl *, const Decl *>, 1>>
+  llvm::DenseMap<const IdentifierInfo *,
+                 SmallVector<std::pair<const NamedDecl *, const Decl *>, 1>>
       NameToDecls;
 };
 
diff --git a/clang-tools-extra/clang-tidy/misc/ConfusableTable/BuildConfusableTable.cpp b/clang-tools-extra/clang-tidy/misc/ConfusableTable/BuildConfusableTable.cpp
index f5dcc7f4edcb6..e041e83ccb2fd 100644
--- a/clang-tools-extra/clang-tidy/misc/ConfusableTable/BuildConfusableTable.cpp
+++ b/clang-tools-extra/clang-tidy/misc/ConfusableTable/BuildConfusableTable.cpp
@@ -37,7 +37,7 @@ int main(int argc, char *argv[]) {
       return 2;
     }
 
-    const llvm::StringRef From = Values[0].trim();
+    const StringRef From = Values[0].trim();
     llvm::UTF32 CodePoint = 0;
     From.getAsInteger(16, CodePoint);
 
diff --git a/clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.h b/clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.h
index 12ad1b1e0e220..16760f439d014 100644
--- a/clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.h
+++ b/clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.h
@@ -25,7 +25,7 @@ namespace clang::tidy::misc {
 ///  https://clang.llvm.org/extra/clang-tidy/checks/misc/coroutine-hostile-raii.html
 class CoroutineHostileRAIICheck : public ClangTidyCheck {
 public:
-  CoroutineHostileRAIICheck(llvm::StringRef Name, ClangTidyContext *Context);
+  CoroutineHostileRAIICheck(StringRef Name, ClangTidyContext *Context);
 
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus20;
diff --git a/clang-tools-extra/clang-tidy/misc/HeaderIncludeCycleCheck.cpp b/clang-tools-extra/clang-tidy/misc/HeaderIncludeCycleCheck.cpp
index d69f3bbd168cc..be554c0c7365f 100644
--- a/clang-tools-extra/clang-tidy/misc/HeaderIncludeCycleCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/HeaderIncludeCycleCheck.cpp
@@ -43,7 +43,7 @@ class CyclicDependencyCallbacks : public PPCallbacks {
   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                    SrcMgr::CharacteristicKind FileType,
                    FileID PrevFID) override {
-    if (FileType != clang::SrcMgr::C_User)
+    if (FileType != SrcMgr::C_User)
       return;
 
     if (Reason != EnterFile && Reason != ExitFile)
@@ -77,7 +77,7 @@ class CyclicDependencyCallbacks : public PPCallbacks {
                           OptionalFileEntryRef File, StringRef, StringRef,
                           const Module *, bool,
                           SrcMgr::CharacteristicKind FileType) override {
-    if (FileType != clang::SrcMgr::C_User)
+    if (FileType != SrcMgr::C_User)
       return;
 
     NextToEnter = Range.getBegin();
diff --git a/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.cpp b/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.cpp
index 558c368901f1c..94232fa2ff626 100644
--- a/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.cpp
@@ -123,7 +123,7 @@ void IncludeCleanerCheck::check(const MatchFinder::MatchResult &Result) {
   const FileEntry *MainFile = SM->getFileEntryForID(SM->getMainFileID());
   llvm::DenseSet<const include_cleaner::Include *> Used;
   std::vector<MissingIncludeInfo> Missing;
-  llvm::SmallVector<Decl *> MainFileDecls;
+  SmallVector<Decl *> MainFileDecls;
   for (Decl *D : Result.Nodes.getNodeAs<TranslationUnitDecl>("top")->decls()) {
     if (!SM->isWrittenInMainFile(SM->getExpansionLoc(D->getLocation())))
       continue;
@@ -200,7 +200,7 @@ void IncludeCleanerCheck::check(const MatchFinder::MatchResult &Result) {
     Unused.push_back(&I);
   }
 
-  const llvm::StringRef Code = SM->getBufferData(SM->getMainFileID());
+  const StringRef Code = SM->getBufferData(SM->getMainFileID());
   auto FileStyle =
       format::getStyle(format::DefaultFormatStyle, getCurrentMainFile(),
                        format::DefaultFallbackStyle, Code,
@@ -227,14 +227,14 @@ void IncludeCleanerCheck::check(const MatchFinder::MatchResult &Result) {
     for (const auto &Inc : Missing) {
       const std::string Spelling = include_cleaner::spellHeader(
           {Inc.Missing, PP->getHeaderSearchInfo(), MainFile});
-      const bool Angled = llvm::StringRef{Spelling}.starts_with("<");
+      const bool Angled = StringRef{Spelling}.starts_with("<");
       // We might suggest insertion of an existing include in edge cases, e.g.,
       // include is present in a PP-disabled region, or spelling of the header
       // turns out to be the same as one of the unresolved includes in the
       // main file.
-      if (auto Replacement = HeaderIncludes.insert(
-              llvm::StringRef{Spelling}.trim("\"<>"), Angled,
-              tooling::IncludeDirective::Include)) {
+      if (auto Replacement =
+              HeaderIncludes.insert(StringRef{Spelling}.trim("\"<>"), Angled,
+                                    tooling::IncludeDirective::Include)) {
         const DiagnosticBuilder DB =
             diag(SM->getSpellingLoc(Inc.SymRef.RefLocation),
                  "no header providing \"%0\" is directly included")
diff --git a/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.h b/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.h
index 619d8191ab41f..ab97565775e46 100644
--- a/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/IncludeCleanerCheck.h
@@ -51,7 +51,7 @@ class IncludeCleanerCheck : public ClangTidyCheck {
   const bool UnusedIncludes;
   // Whether to report missing includes.
   const bool MissingIncludes;
-  llvm::SmallVector<llvm::Regex> IgnoreHeadersRegex;
+  SmallVector<llvm::Regex> IgnoreHeadersRegex;
   bool shouldIgnore(const include_cleaner::Header &H);
 };
 
diff --git a/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.h b/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.h
index 36af07c9fbd17..7053e5d9fc1bc 100644
--- a/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/NewDeleteOverloadsCheck.h
@@ -14,8 +14,7 @@
 namespace clang::tidy::misc {
 
 class NewDeleteOverloadsCheck : public ClangTidyCheck {
-  llvm::DenseMap<const CXXRecordDecl *,
-                 llvm::SmallVector<const FunctionDecl *, 4>>
+  llvm::DenseMap<const CXXRecordDecl *, SmallVector<const FunctionDecl *, 4>>
       Overloads;
 
 public:
diff --git a/clang-tools-extra/clang-tidy/misc/NoRecursionCheck.cpp b/clang-tools-extra/clang-tidy/misc/NoRecursionCheck.cpp
index 8bcbb61961fa6..e1c0612336df5 100644
--- a/clang-tools-extra/clang-tidy/misc/NoRecursionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/NoRecursionCheck.cpp
@@ -148,8 +148,7 @@ template <typename T, unsigned SmallSize> class SmartSmallSetVector {
 constexpr unsigned SmallCallStackSize = 16;
 constexpr unsigned SmallSCCSize = 32;
 
-using CallStackTy =
-    llvm::SmallVector<CallGraphNode::CallRecord, SmallCallStackSize>;
+using CallStackTy = SmallVector<CallGraphNode::CallRecord, SmallCallStackSize>;
 
 } // namespace
 
diff --git a/clang-tools-extra/clang-tidy/misc/OverrideWithDifferentVisibilityCheck.h b/clang-tools-extra/clang-tidy/misc/OverrideWithDifferentVisibilityCheck.h
index d8da30bd738d6..7300be0002c55 100644
--- a/clang-tools-extra/clang-tidy/misc/OverrideWithDifferentVisibilityCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/OverrideWithDifferentVisibilityCheck.h
@@ -35,7 +35,7 @@ class OverrideWithDifferentVisibilityCheck : public ClangTidyCheck {
   ChangeKind DetectVisibilityChange;
   bool CheckDestructors;
   bool CheckOperators;
-  std::vector<llvm::StringRef> IgnoredFunctions;
+  std::vector<StringRef> IgnoredFunctions;
 };
 
 } // namespace clang::tidy::misc
diff --git a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
index 945da332130a3..9db297990b274 100644
--- a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
@@ -868,14 +868,14 @@ static bool areExprsMacroAndNonMacro(const Expr *&LhsExpr,
   return LhsLoc.isMacroID() != RhsLoc.isMacroID();
 }
 
-static bool areStringsSameIgnoreSpaces(const llvm::StringRef Left,
-                                       const llvm::StringRef Right) {
+static bool areStringsSameIgnoreSpaces(const StringRef Left,
+                                       const StringRef Right) {
   if (Left == Right)
     return true;
 
   // Do running comparison ignoring spaces
-  llvm::StringRef L = Left.trim();
-  llvm::StringRef R = Right.trim();
+  StringRef L = Left.trim();
+  StringRef R = Right.trim();
   while (!L.empty() && !R.empty()) {
     L = L.ltrim();
     R = R.ltrim();
@@ -905,9 +905,9 @@ static bool areExprsSameMacroOrLiteral(const BinaryOperator *BinOp,
     // Left is macro so right macro too
     if (Rsr.getBegin().isMacroID()) {
       // Both sides are macros so they are same macro or literal
-      const llvm::StringRef L = Lexer::getSourceText(
+      const StringRef L = Lexer::getSourceText(
           CharSourceRange::getTokenRange(Lsr), SM, Context->getLangOpts());
-      const llvm::StringRef R = Lexer::getSourceText(
+      const StringRef R = Lexer::getSourceText(
           CharSourceRange::getTokenRange(Rsr), SM, Context->getLangOpts());
       return areStringsSameIgnoreSpaces(L, R);
     }
diff --git a/clang-tools-extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp b/clang-tools-extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp
index fc739a020c1ef..8dae11d236919 100644
--- a/clang-tools-extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/ThrowByValueCatchByReferenceCheck.cpp
@@ -51,8 +51,8 @@ bool ThrowByValueCatchByReferenceCheck::isFunctionParameter(
 bool ThrowByValueCatchByReferenceCheck::isCatchVariable(
     const DeclRefExpr *DeclRefExpr) {
   auto *ValueDecl = DeclRefExpr->getDecl();
-  if (auto *VarDecl = dyn_cast<clang::VarDecl>(ValueDecl))
-    return VarDecl->isExceptionVariable();
+  if (auto *Var = dyn_cast<VarDecl>(ValueDecl))
+    return Var->isExceptionVariable();
   return false;
 }
 
diff --git a/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp
index cb5eee4d0dd9c..b5011d982bf76 100644
--- a/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp
@@ -20,13 +20,13 @@ namespace clang::tidy::misc {
 namespace {
 
 AST_MATCHER_P(DeducedTemplateSpecializationType, refsToTemplatedDecl,
-              clang::ast_matchers::internal::Matcher<NamedDecl>, DeclMatcher) {
+              ast_matchers::internal::Matcher<NamedDecl>, DeclMatcher) {
   if (const auto *TD = Node.getTemplateName().getAsTemplateDecl())
     return DeclMatcher.matches(*TD, Finder, Builder);
   return false;
 }
 
-AST_MATCHER_P(Type, asTagDecl, clang::ast_matchers::internal::Matcher<TagDecl>,
+AST_MATCHER_P(Type, asTagDecl, ast_matchers::internal::Matcher<TagDecl>,
               DeclMatcher) {
   if (const TagDecl *ND = Node.getAsTagDecl())
     return DeclMatcher.matches(*ND, Finder, Builder);
diff --git a/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp b/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp
index ed36d486a1734..90643264a7d29 100644
--- a/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp
@@ -24,7 +24,7 @@ AST_POLYMORPHIC_MATCHER_P(isInHeaderFile,
 }
 
 AST_MATCHER(FunctionDecl, isMemberFunction) {
-  return llvm::isa<CXXMethodDecl>(&Node);
+  return isa<CXXMethodDecl>(&Node);
 }
 AST_MATCHER(VarDecl, isStaticDataMember) { return Node.isStaticDataMember(); }
 } // namespace
@@ -52,8 +52,7 @@ void UseAnonymousNamespaceCheck::registerMatchers(MatchFinder *Finder) {
 
 void UseAnonymousNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
   if (const auto *MatchedDecl = Result.Nodes.getNodeAs<NamedDecl>("x")) {
-    const StringRef Type =
-        llvm::isa<VarDecl>(MatchedDecl) ? "variable" : "function";
+    const StringRef Type = isa<VarDecl>(MatchedDecl) ? "variable" : "function";
     diag(MatchedDecl->getLocation(),
          "%0 %1 declared 'static', move to anonymous namespace instead")
         << Type << MatchedDecl;
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidBindCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidBindCheck.cpp
index 3f522041b863d..dd8fb6889e14d 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidBindCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidBindCheck.cpp
@@ -391,7 +391,7 @@ static std::vector<const FunctionDecl *>
 findCandidateCallOperators(const CXXRecordDecl *RecordDecl, size_t NumArgs) {
   std::vector<const FunctionDecl *> Candidates;
 
-  for (const clang::CXXMethodDecl *Method : RecordDecl->methods()) {
+  for (const CXXMethodDecl *Method : RecordDecl->methods()) {
     const OverloadedOperatorKind OOK = Method->getOverloadedOperator();
 
     if (OOK != OverloadedOperatorKind::OO_Call)
@@ -404,7 +404,7 @@ findCandidateCallOperators(const CXXRecordDecl *RecordDecl, size_t NumArgs) {
   }
 
   // Find templated operator(), if any.
-  for (const clang::Decl *D : RecordDecl->decls()) {
+  for (const Decl *D : RecordDecl->decls()) {
     const auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
     if (!FTD)
       continue;
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index b153e3fb0b824..b056255b8e23b 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -17,49 +17,44 @@ namespace clang::tidy::modernize {
 
 template <typename TargetType, typename NodeType>
 static const TargetType *getAs(const NodeType *Node) {
-  if constexpr (std::is_same_v<NodeType, clang::DynTypedNode>)
+  if constexpr (std::is_same_v<NodeType, DynTypedNode>)
     return Node->template get<TargetType>();
   else
-    return llvm::dyn_cast<TargetType>(Node);
+    return dyn_cast<TargetType>(Node);
 }
 
 namespace {
 
-AST_MATCHER(clang::TypeLoc, hasValidBeginLoc) {
-  return Node.getBeginLoc().isValid();
-}
+AST_MATCHER(TypeLoc, hasValidBeginLoc) { return Node.getBeginLoc().isValid(); }
 
-AST_MATCHER_P(clang::TypeLoc, hasType,
-              clang::ast_matchers::internal::Matcher<clang::Type>,
+AST_MATCHER_P(TypeLoc, hasType, ast_matchers::internal::Matcher<Type>,
               InnerMatcher) {
-  const clang::Type *TypeNode = Node.getTypePtr();
+  const Type *TypeNode = Node.getTypePtr();
   return TypeNode != nullptr &&
          InnerMatcher.matches(*TypeNode, Finder, Builder);
 }
 
-AST_MATCHER(clang::RecordDecl, isExternCContext) {
-  return Node.isExternCContext();
-}
+AST_MATCHER(RecordDecl, isExternCContext) { return Node.isExternCContext(); }
 
-AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
-  const clang::DeclContext *DC = Node.getDeclContext();
-  const auto *FD = llvm::dyn_cast<clang::FunctionDecl>(DC);
+AST_MATCHER(ParmVarDecl, isArgvOfMain) {
+  const DeclContext *DC = Node.getDeclContext();
+  const auto *FD = dyn_cast<FunctionDecl>(DC);
   return FD ? FD->isMain() : false;
 }
 
-AST_MATCHER(clang::TypeLoc, isWithinImplicitTemplateInstantiation) {
+AST_MATCHER(TypeLoc, isWithinImplicitTemplateInstantiation) {
   const auto IsImplicitTemplateInstantiation = [](const auto *Node) {
     const auto IsImplicitInstantiation = [](const auto *Node) {
       return (Node != nullptr) && (Node->getTemplateSpecializationKind() ==
                                    TSK_ImplicitInstantiation);
     };
-    return (IsImplicitInstantiation(getAs<clang::CXXRecordDecl>(Node)) ||
-            IsImplicitInstantiation(getAs<clang::FunctionDecl>(Node)) ||
-            IsImplicitInstantiation(getAs<clang::VarDecl>(Node)));
+    return (IsImplicitInstantiation(getAs<CXXRecordDecl>(Node)) ||
+            IsImplicitInstantiation(getAs<FunctionDecl>(Node)) ||
+            IsImplicitInstantiation(getAs<VarDecl>(Node)));
   };
 
   DynTypedNodeList ParentNodes = Finder->getASTContext().getParents(Node);
-  const clang::NamedDecl *ParentDecl = nullptr;
+  const NamedDecl *ParentDecl = nullptr;
   while (!ParentNodes.empty()) {
     const DynTypedNode &ParentNode = ParentNodes[0];
     if (IsImplicitTemplateInstantiation(&ParentNode))
@@ -68,14 +63,14 @@ AST_MATCHER(clang::TypeLoc, isWithinImplicitTemplateInstantiation) {
     // in case of a `NamedDecl` as parent node, it is more efficient to proceed
     // with the upward traversal via DeclContexts (see below) instead of via
     // parent nodes
-    if ((ParentDecl = ParentNode.template get<clang::NamedDecl>()))
+    if ((ParentDecl = ParentNode.get<NamedDecl>()))
       break;
 
     ParentNodes = Finder->getASTContext().getParents(ParentNode);
   }
 
   if (ParentDecl != nullptr) {
-    const clang::DeclContext *DeclContext = ParentDecl->getDeclContext();
+    const DeclContext *DeclContext = ParentDecl->getDeclContext();
     while (DeclContext != nullptr) {
       if (IsImplicitTemplateInstantiation(DeclContext))
         return true;
@@ -141,7 +136,7 @@ void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
       Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
   const bool IsVLA = ArrayTypeLoc.getTypePtr()->isVariableArrayType();
   enum class RecommendType { Array, Vector, Span };
-  llvm::SmallVector<const char *> RecommendTypes{};
+  SmallVector<const char *> RecommendTypes{};
   if (IsVLA) {
     RecommendTypes.push_back("'std::vector'");
   } else if (ArrayTypeLoc.getTypePtr()->isIncompleteArrayType() && IsInParam) {
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCStyleCastCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCStyleCastCheck.cpp
index 94eb0a59c6fbd..7010b8774deca 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCStyleCastCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCStyleCastCheck.cpp
@@ -58,7 +58,7 @@ static bool pointedUnqualifiedTypesAreEqual(QualType T1, QualType T2) {
   return T1.getUnqualifiedType() == T2.getUnqualifiedType();
 }
 
-static clang::CharSourceRange getReplaceRange(const ExplicitCastExpr *Expr) {
+static CharSourceRange getReplaceRange(const ExplicitCastExpr *Expr) {
   if (const auto *CastExpr = dyn_cast<CStyleCastExpr>(Expr))
     return CharSourceRange::getCharRange(
         CastExpr->getLParenLoc(),
@@ -254,7 +254,7 @@ void AvoidCStyleCastCheck::check(const MatchFinder::MatchResult &Result) {
     }
 
     [[fallthrough]];
-  case clang::CK_IntegralCast:
+  case CK_IntegralCast:
     // Convert integral and no-op casts between builtin types and enums to
     // static_cast. A cast from enum to integer may be unnecessary, but it's
     // still retained.
diff --git a/clang-tools-extra/clang-tidy/modernize/ConcatNestedNamespacesCheck.h b/clang-tools-extra/clang-tidy/modernize/ConcatNestedNamespacesCheck.h
index 9886cb5a2d7d9..74585e39105ad 100644
--- a/clang-tools-extra/clang-tidy/modernize/ConcatNestedNamespacesCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/ConcatNestedNamespacesCheck.h
@@ -15,9 +15,9 @@
 
 namespace clang::tidy::modernize {
 
-using NamespaceName = llvm::SmallString<40>;
+using NamespaceName = SmallString<40>;
 
-class NS : public llvm::SmallVector<const NamespaceDecl *, 6> {
+class NS : public SmallVector<const NamespaceDecl *, 6> {
 public:
   std::optional<SourceRange>
   getCleanedNamespaceFrontRange(const SourceManager &SM,
@@ -43,7 +43,7 @@ class ConcatNestedNamespacesCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  using NamespaceContextVec = llvm::SmallVector<NS, 6>;
+  using NamespaceContextVec = SmallVector<NS, 6>;
 
   void reportDiagnostic(const SourceManager &SM, const LangOptions &LangOpts);
   NamespaceContextVec Namespaces;
diff --git a/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp b/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp
index 2d63da2fef974..0179f649a0e9f 100644
--- a/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp
@@ -1074,7 +1074,7 @@ void LoopConvertCheck::check(const MatchFinder::MatchResult &Result) {
                Finder.aliasFromForInit(), Loop, Descriptor);
 }
 
-llvm::StringRef LoopConvertCheck::getReverseFunction() const {
+StringRef LoopConvertCheck::getReverseFunction() const {
   if (!ReverseFunction.empty())
     return ReverseFunction;
   if (UseReverseRanges)
@@ -1082,7 +1082,7 @@ llvm::StringRef LoopConvertCheck::getReverseFunction() const {
   return "";
 }
 
-llvm::StringRef LoopConvertCheck::getReverseHeader() const {
+StringRef LoopConvertCheck::getReverseHeader() const {
   if (!ReverseHeader.empty())
     return ReverseHeader;
   if (UseReverseRanges && ReverseFunction.empty())
diff --git a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.h b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.h
index 5d0800d8e7880..0c295fd5d0820 100644
--- a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.h
+++ b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.h
@@ -15,8 +15,6 @@
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
 #include <algorithm>
 #include <memory>
 #include <string>
@@ -32,29 +30,26 @@ enum LoopFixerKind {
 };
 
 /// A map used to walk the AST in reverse: maps child Stmt to parent Stmt.
-using StmtParentMap = llvm::DenseMap<const clang::Stmt *, const clang::Stmt *>;
+using StmtParentMap = llvm::DenseMap<const Stmt *, const Stmt *>;
 
 /// A map used to walk the AST in reverse:
 ///  maps VarDecl to the to parent DeclStmt.
-using DeclParentMap =
-    llvm::DenseMap<const clang::VarDecl *, const clang::DeclStmt *>;
+using DeclParentMap = llvm::DenseMap<const VarDecl *, const DeclStmt *>;
 
 /// A map used to track which variables have been removed by a refactoring pass.
 /// It maps the parent ForStmt to the removed index variable's VarDecl.
-using ReplacedVarsMap =
-    llvm::DenseMap<const clang::ForStmt *, const clang::VarDecl *>;
+using ReplacedVarsMap = llvm::DenseMap<const ForStmt *, const VarDecl *>;
 
 /// A map used to remember the variable names generated in a Stmt
-using StmtGeneratedVarNameMap =
-    llvm::DenseMap<const clang::Stmt *, std::string>;
+using StmtGeneratedVarNameMap = llvm::DenseMap<const Stmt *, std::string>;
 
 /// A vector used to store the AST subtrees of an Expr.
-using ComponentVector = llvm::SmallVector<const clang::Expr *, 16>;
+using ComponentVector = SmallVector<const Expr *, 16>;
 
 /// Class used build the reverse AST properties needed to detect
 /// name conflicts and free variables.
 class StmtAncestorASTVisitor
-    : public clang::RecursiveASTVisitor<StmtAncestorASTVisitor> {
+    : public RecursiveASTVisitor<StmtAncestorASTVisitor> {
 public:
   StmtAncestorASTVisitor() { StmtStack.push_back(nullptr); }
 
@@ -72,50 +67,50 @@ class StmtAncestorASTVisitor
   /// Accessor for DeclParents.
   const DeclParentMap &getDeclToParentStmtMap() { return DeclParents; }
 
-  friend class clang::RecursiveASTVisitor<StmtAncestorASTVisitor>;
+  friend class RecursiveASTVisitor<StmtAncestorASTVisitor>;
 
 private:
   StmtParentMap StmtAncestors;
   DeclParentMap DeclParents;
-  llvm::SmallVector<const clang::Stmt *, 16> StmtStack;
+  SmallVector<const Stmt *, 16> StmtStack;
 
-  bool TraverseStmt(clang::Stmt *Statement);
-  bool VisitDeclStmt(clang::DeclStmt *Statement);
+  bool TraverseStmt(Stmt *Statement);
+  bool VisitDeclStmt(DeclStmt *Statement);
 };
 
 /// Class used to find the variables and member expressions on which an
 /// arbitrary expression depends.
 class ComponentFinderASTVisitor
-    : public clang::RecursiveASTVisitor<ComponentFinderASTVisitor> {
+    : public RecursiveASTVisitor<ComponentFinderASTVisitor> {
 public:
   ComponentFinderASTVisitor() = default;
 
   /// Find the components of an expression and place them in a ComponentVector.
-  void findExprComponents(const clang::Expr *SourceExpr) {
-    TraverseStmt(const_cast<clang::Expr *>(SourceExpr));
+  void findExprComponents(const Expr *SourceExpr) {
+    TraverseStmt(const_cast<Expr *>(SourceExpr));
   }
 
   /// Accessor for Components.
   const ComponentVector &getComponents() { return Components; }
 
-  friend class clang::RecursiveASTVisitor<ComponentFinderASTVisitor>;
+  friend class RecursiveASTVisitor<ComponentFinderASTVisitor>;
 
 private:
   ComponentVector Components;
 
-  bool VisitDeclRefExpr(clang::DeclRefExpr *E);
-  bool VisitMemberExpr(clang::MemberExpr *Member);
+  bool VisitDeclRefExpr(DeclRefExpr *E);
+  bool VisitMemberExpr(MemberExpr *Member);
 };
 
 /// Class used to determine if an expression is dependent on a variable declared
 /// inside of the loop where it would be used.
 class DependencyFinderASTVisitor
-    : public clang::RecursiveASTVisitor<DependencyFinderASTVisitor> {
+    : public RecursiveASTVisitor<DependencyFinderASTVisitor> {
 public:
   DependencyFinderASTVisitor(const StmtParentMap *StmtParents,
                              const DeclParentMap *DeclParents,
                              const ReplacedVarsMap *ReplacedVars,
-                             const clang::Stmt *ContainingStmt)
+                             const Stmt *ContainingStmt)
       : StmtParents(StmtParents), DeclParents(DeclParents),
         ContainingStmt(ContainingStmt), ReplacedVars(ReplacedVars) {}
 
@@ -149,31 +144,30 @@ class DependencyFinderASTVisitor
   /// In order to avoid this, this class looks at the container expression
   /// `arr[k]` and decides whether or not it contains a sub-expression declared
   /// within the loop body.
-  bool dependsOnInsideVariable(const clang::Stmt *Body) {
+  bool dependsOnInsideVariable(const Stmt *Body) {
     DependsOnInsideVariable = false;
-    TraverseStmt(const_cast<clang::Stmt *>(Body));
+    TraverseStmt(const_cast<Stmt *>(Body));
     return DependsOnInsideVariable;
   }
 
-  friend class clang::RecursiveASTVisitor<DependencyFinderASTVisitor>;
+  friend class RecursiveASTVisitor<DependencyFinderASTVisitor>;
 
 private:
   const StmtParentMap *StmtParents;
   const DeclParentMap *DeclParents;
-  const clang::Stmt *ContainingStmt;
+  const Stmt *ContainingStmt;
   const ReplacedVarsMap *ReplacedVars;
   bool DependsOnInsideVariable;
 
-  bool VisitVarDecl(clang::VarDecl *V);
-  bool VisitDeclRefExpr(clang::DeclRefExpr *D);
+  bool VisitVarDecl(VarDecl *V);
+  bool VisitDeclRefExpr(DeclRefExpr *D);
 };
 
 /// Class used to determine if any declarations used in a Stmt would conflict
 /// with a particular identifier. This search includes the names that don't
 /// actually appear in the AST (i.e. created by a refactoring tool) by including
 /// a map from Stmts to generated names associated with those stmts.
-class DeclFinderASTVisitor
-    : public clang::RecursiveASTVisitor<DeclFinderASTVisitor> {
+class DeclFinderASTVisitor : public RecursiveASTVisitor<DeclFinderASTVisitor> {
 public:
   DeclFinderASTVisitor(const StringRef &Name,
                        const StmtGeneratedVarNameMap *GeneratedDecls)
@@ -182,13 +176,13 @@ class DeclFinderASTVisitor
   /// Attempts to find any usages of variables name Name in Body, returning
   /// true when it is used in Body. This includes the generated loop variables
   /// of ForStmts which have already been transformed.
-  bool findUsages(const clang::Stmt *Body) {
+  bool findUsages(const Stmt *Body) {
     Found = false;
-    TraverseStmt(const_cast<clang::Stmt *>(Body));
+    TraverseStmt(const_cast<Stmt *>(Body));
     return Found;
   }
 
-  friend class clang::RecursiveASTVisitor<DeclFinderASTVisitor>;
+  friend class RecursiveASTVisitor<DeclFinderASTVisitor>;
 
 private:
   std::string Name;
@@ -197,10 +191,10 @@ class DeclFinderASTVisitor
   const StmtGeneratedVarNameMap *GeneratedDecls;
   bool Found = false;
 
-  bool VisitForStmt(clang::ForStmt *);
-  bool VisitNamedDecl(clang::NamedDecl *);
-  bool VisitDeclRefExpr(clang::DeclRefExpr *);
-  bool VisitTypeLoc(clang::TypeLoc);
+  bool VisitForStmt(ForStmt *);
+  bool VisitNamedDecl(NamedDecl *);
+  bool VisitDeclRefExpr(DeclRefExpr *);
+  bool VisitTypeLoc(TypeLoc);
 };
 
 /// The information needed to describe a valid convertible usage
@@ -270,7 +264,7 @@ class Confidence {
 };
 
 // The main computational result of ForLoopIndexVisitor.
-using UsageResult = llvm::SmallVector<Usage, 8>;
+using UsageResult = SmallVector<Usage, 8>;
 
 // General functions used by ForLoopIndexUseVisitor and LoopConvertCheck.
 const Expr *digThroughConstructorsConversions(const Expr *E);
@@ -385,7 +379,7 @@ class ForLoopIndexUseVisitor
   ///
   /// If any of these expressions are encountered outside of an acceptable usage
   /// of the loop element, lower our confidence level.
-  llvm::SmallVector<std::pair<const Expr *, llvm::FoldingSetNodeID>, 16>
+  SmallVector<std::pair<const Expr *, llvm::FoldingSetNodeID>, 16>
       DependentExprs;
 
   /// The parent-in-waiting. Will become the real parent once we traverse down
@@ -435,10 +429,9 @@ class VariableNamer {
   };
 
   VariableNamer(StmtGeneratedVarNameMap *GeneratedDecls,
-                const StmtParentMap *ReverseAST, const clang::Stmt *SourceStmt,
-                const clang::VarDecl *OldIndex,
-                const clang::ValueDecl *TheContainer,
-                const clang::ASTContext *Context, NamingStyle Style)
+                const StmtParentMap *ReverseAST, const Stmt *SourceStmt,
+                const VarDecl *OldIndex, const ValueDecl *TheContainer,
+                const ASTContext *Context, NamingStyle Style)
       : GeneratedDecls(GeneratedDecls), ReverseAST(ReverseAST),
         SourceStmt(SourceStmt), OldIndex(OldIndex), TheContainer(TheContainer),
         Context(Context), Style(Style) {}
@@ -453,15 +446,15 @@ class VariableNamer {
 private:
   StmtGeneratedVarNameMap *GeneratedDecls;
   const StmtParentMap *ReverseAST;
-  const clang::Stmt *SourceStmt;
-  const clang::VarDecl *OldIndex;
-  const clang::ValueDecl *TheContainer;
-  const clang::ASTContext *Context;
+  const Stmt *SourceStmt;
+  const VarDecl *OldIndex;
+  const ValueDecl *TheContainer;
+  const ASTContext *Context;
   const NamingStyle Style;
 
   // Determine whether or not a declaration that would conflict with Symbol
   // exists in an outer context or in any statement contained in SourceStmt.
-  bool declarationExists(llvm::StringRef Symbol);
+  bool declarationExists(StringRef Symbol);
 };
 
 } // namespace clang::tidy::modernize
diff --git a/clang-tools-extra/clang-tidy/modernize/MakeUniqueCheck.cpp b/clang-tools-extra/clang-tidy/modernize/MakeUniqueCheck.cpp
index b13d95633c12e..91a1f22c0033d 100644
--- a/clang-tools-extra/clang-tidy/modernize/MakeUniqueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/MakeUniqueCheck.cpp
@@ -12,8 +12,7 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::modernize {
 
-MakeUniqueCheck::MakeUniqueCheck(StringRef Name,
-                                 clang::tidy::ClangTidyContext *Context)
+MakeUniqueCheck::MakeUniqueCheck(StringRef Name, ClangTidyContext *Context)
     : MakeSmartPtrCheck(Name, Context, "std::make_unique"),
       RequireCPlusPlus14(Options.get("MakeSmartPtrFunction", "").empty()) {}
 
diff --git a/clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.cpp b/clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.cpp
index f4592950fc05e..3f61a2d5d8bba 100644
--- a/clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.cpp
@@ -13,7 +13,9 @@
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Lex/Lexer.h"
 
-using namespace clang;
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
 
 namespace {
 
@@ -21,15 +23,11 @@ struct FindArgsResult {
   const Expr *First;
   const Expr *Last;
   const Expr *Compare;
-  SmallVector<const clang::Expr *, 2> Args;
+  SmallVector<const Expr *, 2> Args;
 };
 
 } // anonymous namespace
 
-using namespace clang::ast_matchers;
-
-namespace clang::tidy::modernize {
-
 static FindArgsResult findArgs(const CallExpr *Call) {
   FindArgsResult Result;
   Result.First = nullptr;
diff --git a/clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp b/clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp
index 2619331cba0b0..77add86cb85c1 100644
--- a/clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp
@@ -173,9 +173,9 @@ static bool hasRValueOverload(const CXXConstructorDecl *Ctor,
         C->getNumParams() != Ctor->getNumParams())
       return false;
     for (int I = 0, E = C->getNumParams(); I < E; ++I) {
-      const clang::QualType CandidateParamType =
+      const QualType CandidateParamType =
           C->parameters()[I]->getType().getCanonicalType();
-      const clang::QualType CtorParamType =
+      const QualType CtorParamType =
           Ctor->parameters()[I]->getType().getCanonicalType();
       const bool IsLValueRValuePair =
           CtorParamType->isLValueReferenceType() &&
diff --git a/clang-tools-extra/clang-tidy/modernize/ReplaceDisallowCopyAndAssignMacroCheck.cpp b/clang-tools-extra/clang-tidy/modernize/ReplaceDisallowCopyAndAssignMacroCheck.cpp
index b10e2cc1c2e2e..8d09b9a88f0ad 100644
--- a/clang-tools-extra/clang-tidy/modernize/ReplaceDisallowCopyAndAssignMacroCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/ReplaceDisallowCopyAndAssignMacroCheck.cpp
@@ -39,7 +39,7 @@ class ReplaceDisallowCopyAndAssignMacroCallbacks : public PPCallbacks {
       // For now we only support simple argument that don't need to be
       // pre-expanded.
       return;
-    const clang::IdentifierInfo *ClassIdent = ClassNameTok->getIdentifierInfo();
+    const IdentifierInfo *ClassIdent = ClassNameTok->getIdentifierInfo();
     if (!ClassIdent)
       return;
 
diff --git a/clang-tools-extra/clang-tidy/modernize/ShrinkToFitCheck.cpp b/clang-tools-extra/clang-tidy/modernize/ShrinkToFitCheck.cpp
index e32ddbf87efe9..a13e270bf85e1 100644
--- a/clang-tools-extra/clang-tidy/modernize/ShrinkToFitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/ShrinkToFitCheck.cpp
@@ -50,7 +50,7 @@ void ShrinkToFitCheck::check(const MatchFinder::MatchResult &Result) {
   if (!MemberCall->getBeginLoc().isMacroID()) {
     const LangOptions &Opts = getLangOpts();
     std::string ReplacementText;
-    if (const auto *UnaryOp = llvm::dyn_cast<UnaryOperator>(Container)) {
+    if (const auto *UnaryOp = dyn_cast<UnaryOperator>(Container)) {
       ReplacementText = std::string(
           Lexer::getSourceText(CharSourceRange::getTokenRange(
                                    UnaryOp->getSubExpr()->getSourceRange()),
diff --git a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp
index 1666987411790..cebab03e2ab03 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp
@@ -428,13 +428,13 @@ void UseAutoCheck::replaceExpr(
 
   // Space after 'auto' to handle cases where the '*' in the pointer type is
   // next to the identifier. This avoids changing 'int *p' into 'autop'.
-  const llvm::StringRef Auto = ShouldReplenishVariableName
-                                   ? (RemoveStars ? "auto " : "auto *")
-                                   : (RemoveStars ? "auto " : "auto");
+  const StringRef Auto = ShouldReplenishVariableName
+                             ? (RemoveStars ? "auto " : "auto *")
+                             : (RemoveStars ? "auto " : "auto");
   const std::string ReplenishedVariableName =
       ShouldReplenishVariableName ? FirstDecl->getQualifiedNameAsString() : "";
   const std::string Replacement =
-      (Auto + llvm::StringRef{ReplenishedVariableName}).str();
+      (Auto + StringRef{ReplenishedVariableName}).str();
   Diag << FixItHint::CreateReplacement(Range, Replacement) << StarRemovals;
 }
 
diff --git a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
index 9521bfcd6ba58..025290df43719 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
@@ -326,12 +326,12 @@ static std::optional<std::string> getConditionText(const Expr *ConditionExpr,
                            SM, LangOpts) == "//";
 
   bool Invalid = false;
-  const llvm::StringRef ConditionText = Lexer::getSourceText(
+  const StringRef ConditionText = Lexer::getSourceText(
       CharSourceRange::getCharRange(ConditionRange), SM, LangOpts, &Invalid);
   if (Invalid)
     return std::nullopt;
 
-  auto AddParens = [&](llvm::StringRef Text) -> std::string {
+  auto AddParens = [&](StringRef Text) -> std::string {
     if (isPrimaryExpression(ConditionExpr))
       return Text.str();
     return "(" + Text.str() + ")";
diff --git a/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
index 5a8f3e3c9e922..5874c061d299f 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
@@ -55,19 +55,19 @@ struct Designators {
 
   unsigned size() { return getCached().size(); }
 
-  std::optional<llvm::StringRef> operator[](const SourceLocation &Location) {
+  std::optional<StringRef> operator[](const SourceLocation &Location) {
     const auto &Designators = getCached();
     const auto Result = Designators.find(Location);
     if (Result == Designators.end())
       return {};
-    const llvm::StringRef Designator = Result->getSecond();
+    const StringRef Designator = Result->getSecond();
     return (Designator.front() == '.' ? Designator.substr(1) : Designator)
         .trim("\0"); // Trim NULL characters appearing on Windows in the
                      // name.
   }
 
 private:
-  using LocationToNameMap = llvm::DenseMap<clang::SourceLocation, std::string>;
+  using LocationToNameMap = llvm::DenseMap<SourceLocation, std::string>;
 
   std::optional<LocationToNameMap> CachedDesignators;
   const InitListExpr *InitList;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp
index c37f23665b68a..5fcc03dea6b42 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp
@@ -51,8 +51,8 @@ AST_MATCHER_P(NamedDecl, hasAnyNameIgnoringTemplates, std::vector<StringRef>,
 }
 
 // Checks if the given matcher is the last argument of the given CallExpr.
-AST_MATCHER_P(CallExpr, hasLastArgument,
-              clang::ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
+AST_MATCHER_P(CallExpr, hasLastArgument, ast_matchers::internal::Matcher<Expr>,
+              InnerMatcher) {
   if (Node.getNumArgs() == 0)
     return false;
 
diff --git a/clang-tools-extra/clang-tidy/modernize/UseIntegerSignComparisonCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseIntegerSignComparisonCheck.cpp
index 574cbea46124b..8128acb055c84 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseIntegerSignComparisonCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseIntegerSignComparisonCheck.cpp
@@ -18,23 +18,21 @@ namespace clang::tidy::modernize {
 
 /// Find if the passed type is the actual "char" type,
 /// not applicable to explicit "signed char" or "unsigned char" types.
-static bool isActualCharType(const clang::QualType &Ty) {
+static bool isActualCharType(const QualType &Ty) {
   using namespace clang;
   const Type *DesugaredType = Ty->getUnqualifiedDesugaredType();
-  if (const auto *BT = llvm::dyn_cast<BuiltinType>(DesugaredType))
+  if (const auto *BT = dyn_cast<BuiltinType>(DesugaredType))
     return (BT->getKind() == BuiltinType::Char_U ||
             BT->getKind() == BuiltinType::Char_S);
   return false;
 }
 
 namespace {
-AST_MATCHER(clang::QualType, isActualChar) {
-  return clang::tidy::modernize::isActualCharType(Node);
-}
+AST_MATCHER(QualType, isActualChar) { return isActualCharType(Node); }
 } // namespace
 
-static BindableMatcher<clang::Stmt>
-intCastExpression(bool IsSigned, StringRef CastBindName = {}) {
+static BindableMatcher<Stmt> intCastExpression(bool IsSigned,
+                                               StringRef CastBindName = {}) {
   // std::cmp_{} functions trigger a compile-time error if either LHS or RHS
   // is a non-integer type, char, enum or bool
   // (unsigned char/ signed char are Ok and can be used).
@@ -134,13 +132,13 @@ void UseIntegerSignComparisonCheck::check(
   SourceRange R2(BinaryOp->getOperatorLoc());
   SourceRange R3(Lexer::getLocForEndOfToken(
       RHS->getEndLoc(), 0, *Result.SourceManager, getLangOpts()));
-  if (const auto *LHSCast = llvm::dyn_cast<ExplicitCastExpr>(LHS)) {
+  if (const auto *LHSCast = dyn_cast<ExplicitCastExpr>(LHS)) {
     SubExprLHS = LHSCast->getSubExpr();
     R1.setEnd(SubExprLHS->getBeginLoc().getLocWithOffset(-1));
     R2.setBegin(Lexer::getLocForEndOfToken(
         SubExprLHS->getEndLoc(), 0, *Result.SourceManager, getLangOpts()));
   }
-  if (const auto *RHSCast = llvm::dyn_cast<ExplicitCastExpr>(RHS)) {
+  if (const auto *RHSCast = dyn_cast<ExplicitCastExpr>(RHS)) {
     SubExprRHS = RHSCast->getSubExpr();
     R2.setEnd(SubExprRHS->getBeginLoc().getLocWithOffset(-1));
     R3.setBegin(Lexer::getLocForEndOfToken(
diff --git a/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
index 7e8d98241118a..4940b5590f803 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseNodiscardCheck.cpp
@@ -17,7 +17,7 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::modernize {
 
 static bool doesNoDiscardMacroExist(ASTContext &Context,
-                                    const llvm::StringRef &MacroId) {
+                                    const StringRef &MacroId) {
   // Don't check for the Macro existence if we are using an attribute
   // either a C++17 standard attribute or pre C++17 syntax
   if (MacroId.starts_with("[[") || MacroId.starts_with("__attribute__"))
@@ -92,11 +92,10 @@ void UseNodiscardCheck::registerMatchers(MatchFinder *Finder) {
           isConst(), isDefinitionOrInline(),
           unless(anyOf(
               returns(voidType()),
-              returns(
-                  hasDeclaration(decl(hasAttr(clang::attr::WarnUnusedResult)))),
+              returns(hasDeclaration(decl(hasAttr(attr::WarnUnusedResult)))),
               isNoReturn(), isOverloadedOperator(), isVariadic(),
               hasTemplateReturnType(), hasClassMutableFields(),
-              isConversionOperator(), hasAttr(clang::attr::WarnUnusedResult),
+              isConversionOperator(), hasAttr(attr::WarnUnusedResult),
               hasType(isInstantiationDependentType()),
               hasAnyParameter(
                   anyOf(parmVarDecl(anyOf(hasType(FunctionObj),
diff --git a/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.cpp
index a170b7e6b7b91..74f15a68d6326 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.cpp
@@ -40,9 +40,8 @@ static bool isLockGuard(const QualType &Type) {
   return false;
 }
 
-static llvm::SmallVector<const VarDecl *>
-getLockGuardsFromDecl(const DeclStmt *DS) {
-  llvm::SmallVector<const VarDecl *> LockGuards;
+static SmallVector<const VarDecl *> getLockGuardsFromDecl(const DeclStmt *DS) {
+  SmallVector<const VarDecl *> LockGuards;
 
   for (const Decl *Decl : DS->decls()) {
     if (const auto *VD = dyn_cast<VarDecl>(Decl)) {
@@ -58,12 +57,12 @@ getLockGuardsFromDecl(const DeclStmt *DS) {
 
 // Scans through the statements in a block and groups consecutive
 // 'std::lock_guard' variable declarations together.
-static llvm::SmallVector<llvm::SmallVector<const VarDecl *>>
+static SmallVector<SmallVector<const VarDecl *>>
 findLocksInCompoundStmt(const CompoundStmt *Block,
                         const ast_matchers::MatchFinder::MatchResult &Result) {
   // store groups of consecutive 'std::lock_guard' declarations
-  llvm::SmallVector<llvm::SmallVector<const VarDecl *>> LockGuardGroups;
-  llvm::SmallVector<const VarDecl *> CurrentLockGuardGroup;
+  SmallVector<SmallVector<const VarDecl *>> LockGuardGroups;
+  SmallVector<const VarDecl *> CurrentLockGuardGroup;
 
   auto AddAndClearCurrentGroup = [&]() {
     if (!CurrentLockGuardGroup.empty()) {
@@ -74,8 +73,7 @@ findLocksInCompoundStmt(const CompoundStmt *Block,
 
   for (const Stmt *Stmt : Block->body()) {
     if (const auto *DS = dyn_cast<DeclStmt>(Stmt)) {
-      const llvm::SmallVector<const VarDecl *> LockGuards =
-          getLockGuardsFromDecl(DS);
+      const SmallVector<const VarDecl *> LockGuards = getLockGuardsFromDecl(DS);
 
       if (!LockGuards.empty()) {
         CurrentLockGuardGroup.append(LockGuards);
@@ -172,7 +170,7 @@ void UseScopedLockCheck::registerMatchers(MatchFinder *Finder) {
 
 void UseScopedLockCheck::check(const MatchFinder::MatchResult &Result) {
   if (const auto *DS = Result.Nodes.getNodeAs<DeclStmt>("lock-decl-single")) {
-    const llvm::SmallVector<const VarDecl *> Decls = getLockGuardsFromDecl(DS);
+    const SmallVector<const VarDecl *> Decls = getLockGuardsFromDecl(DS);
     diagOnMultipleLocks({Decls}, Result);
     return;
   }
@@ -249,9 +247,9 @@ void UseScopedLockCheck::diagOnSingleLock(
 }
 
 void UseScopedLockCheck::diagOnMultipleLocks(
-    const llvm::SmallVector<llvm::SmallVector<const VarDecl *>> &LockGroups,
+    const SmallVector<SmallVector<const VarDecl *>> &LockGroups,
     const ast_matchers::MatchFinder::MatchResult &Result) {
-  for (const llvm::SmallVector<const VarDecl *> &Group : LockGroups) {
+  for (const SmallVector<const VarDecl *> &Group : LockGroups) {
     if (Group.size() == 1) {
       if (WarnOnSingleLocks)
         diagOnSingleLock(Group[0], Result);
diff --git a/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.h b/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.h
index 8f6b5a4b2aaff..7bf4c773984b5 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseScopedLockCheck.h
@@ -38,7 +38,7 @@ class UseScopedLockCheck : public ClangTidyCheck {
   void diagOnSingleLock(const VarDecl *LockGuard,
                         const ast_matchers::MatchFinder::MatchResult &Result);
   void diagOnMultipleLocks(
-      const llvm::SmallVector<llvm::SmallVector<const VarDecl *>> &LockGroups,
+      const SmallVector<SmallVector<const VarDecl *>> &LockGroups,
       const ast_matchers::MatchFinder::MatchResult &Result);
   void diagOnSourceInfo(const TypeSourceInfo *LockGuardSourceInfo,
                         const ast_matchers::MatchFinder::MatchResult &Result);
diff --git a/clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp
index eebd609cc84a8..97d71ef774924 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp
@@ -20,14 +20,13 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::modernize {
 
 static bool isNegativeComparison(const Expr *ComparisonExpr) {
-  if (const auto *Op = llvm::dyn_cast<BinaryOperator>(ComparisonExpr))
+  if (const auto *Op = dyn_cast<BinaryOperator>(ComparisonExpr))
     return Op->getOpcode() == BO_NE;
 
-  if (const auto *Op = llvm::dyn_cast<CXXOperatorCallExpr>(ComparisonExpr))
+  if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(ComparisonExpr))
     return Op->getOperator() == OO_ExclaimEqual;
 
-  if (const auto *Op =
-          llvm::dyn_cast<CXXRewrittenBinaryOperator>(ComparisonExpr))
+  if (const auto *Op = dyn_cast<CXXRewrittenBinaryOperator>(ComparisonExpr))
     return Op->getOperator() == BO_NE;
 
   return false;
diff --git a/clang-tools-extra/clang-tidy/modernize/UseStdNumbersCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseStdNumbersCheck.cpp
index 2b84dcbe4eab8..912c2927d1aee 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseStdNumbersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseStdNumbersCheck.cpp
@@ -36,35 +36,35 @@
 #include <tuple>
 #include <utility>
 
-namespace {
 using namespace clang::ast_matchers;
 using clang::ast_matchers::internal::Matcher;
-using llvm::StringRef;
 
-AST_MATCHER_P2(clang::FloatingLiteral, near, double, Value, double,
-               DiffThreshold) {
+namespace clang::tidy::modernize {
+
+namespace {
+
+AST_MATCHER_P2(FloatingLiteral, near, double, Value, double, DiffThreshold) {
   return std::abs(Node.getValueAsApproximateDouble() - Value) < DiffThreshold;
 }
 
-AST_MATCHER_P(clang::QualType, hasCanonicalTypeUnqualified,
-              Matcher<clang::QualType>, InnerMatcher) {
+AST_MATCHER_P(QualType, hasCanonicalTypeUnqualified, Matcher<QualType>,
+              InnerMatcher) {
   return !Node.isNull() &&
          InnerMatcher.matches(Node->getCanonicalTypeUnqualified(), Finder,
                               Builder);
 }
 
-AST_MATCHER(clang::QualType, isArithmetic) {
+AST_MATCHER(QualType, isArithmetic) {
   return !Node.isNull() && Node->isArithmeticType();
 }
-AST_MATCHER(clang::QualType, isFloating) {
+AST_MATCHER(QualType, isFloating) {
   return !Node.isNull() && Node->isFloatingType();
 }
 
-AST_MATCHER_P(clang::Expr, anyOfExhaustive, std::vector<Matcher<clang::Stmt>>,
-              Exprs) {
+AST_MATCHER_P(Expr, anyOfExhaustive, std::vector<Matcher<Stmt>>, Exprs) {
   bool FoundMatch = false;
   for (const auto &InnerMatcher : Exprs) {
-    clang::ast_matchers::internal::BoundNodesTreeBuilder Result = *Builder;
+    ast_matchers::internal::BoundNodesTreeBuilder Result = *Builder;
     if (InnerMatcher.matches(Node, Finder, &Result)) {
       *Builder = std::move(Result);
       FoundMatch = true;
@@ -79,18 +79,16 @@ AST_MATCHER_P(clang::Expr, anyOfExhaustive, std::vector<Matcher<clang::Stmt>>,
 // the literal of every constant and for formulas' subexpressions that look at
 // literals.
 struct MatchBuilder {
-  auto
-  ignoreParenAndArithmeticCasting(const Matcher<clang::Expr> &Matcher) const {
+  auto ignoreParenAndArithmeticCasting(const Matcher<Expr> &Matcher) const {
     return expr(hasType(qualType(isArithmetic())), ignoringParenCasts(Matcher));
   }
 
-  auto
-  ignoreParenAndFloatingCasting(const Matcher<clang::Expr> &Matcher) const {
+  auto ignoreParenAndFloatingCasting(const Matcher<Expr> &Matcher) const {
     return expr(hasType(qualType(isFloating())), ignoringParenCasts(Matcher));
   }
 
   auto matchMathCall(const StringRef FunctionName,
-                     const Matcher<clang::Expr> &ArgumentMatcher) const {
+                     const Matcher<Expr> &ArgumentMatcher) const {
     auto HasAnyPrecisionName = hasAnyName(
         FunctionName, (FunctionName + "l").str(),
         (FunctionName + "f").str()); // Support long double(l) and float(f).
@@ -100,7 +98,7 @@ struct MatchBuilder {
                  hasArgument(0, ArgumentMatcher))));
   }
 
-  auto matchSqrt(const Matcher<clang::Expr> &ArgumentMatcher) const {
+  auto matchSqrt(const Matcher<Expr> &ArgumentMatcher) const {
     return matchMathCall("sqrt", ArgumentMatcher);
   }
 
@@ -148,7 +146,7 @@ struct MatchBuilder {
     return expr(anyOf(Int, Float, Dref));
   }
 
-  auto match1Div(const Matcher<clang::Expr> &Match) const {
+  auto match1Div(const Matcher<Expr> &Match) const {
     return binaryOperator(hasOperatorName("/"), hasLHS(matchValue(1)),
                           hasRHS(Match));
   }
@@ -266,24 +264,23 @@ static std::string getCode(const StringRef Constant, const bool IsFloat,
   return ("std::numbers::" + Constant).str();
 }
 
-static bool isRangeOfCompleteMacro(const clang::SourceRange &Range,
-                                   const clang::SourceManager &SM,
-                                   const clang::LangOptions &LO) {
+static bool isRangeOfCompleteMacro(const SourceRange &Range,
+                                   const SourceManager &SM,
+                                   const LangOptions &LO) {
   if (!Range.getBegin().isMacroID())
     return false;
-  if (!clang::Lexer::isAtStartOfMacroExpansion(Range.getBegin(), SM, LO))
+  if (!Lexer::isAtStartOfMacroExpansion(Range.getBegin(), SM, LO))
     return false;
 
   if (!Range.getEnd().isMacroID())
     return false;
 
-  if (!clang::Lexer::isAtEndOfMacroExpansion(Range.getEnd(), SM, LO))
+  if (!Lexer::isAtEndOfMacroExpansion(Range.getEnd(), SM, LO))
     return false;
 
   return true;
 }
 
-namespace clang::tidy::modernize {
 UseStdNumbersCheck::UseStdNumbersCheck(const StringRef Name,
                                        ClangTidyContext *const Context)
     : ClangTidyCheck(Name, Context),
@@ -301,7 +298,7 @@ UseStdNumbersCheck::UseStdNumbersCheck(const StringRef Name,
 
 void UseStdNumbersCheck::registerMatchers(MatchFinder *const Finder) {
   const auto Matches = MatchBuilder{DiffThreshold};
-  const std::vector<Matcher<clang::Stmt>> ConstantMatchers = {
+  const std::vector<Matcher<Stmt>> ConstantMatchers = {
       Matches.matchLog2Euler(),     Matches.matchLog10Euler(),
       Matches.matchEulerTopLevel(), Matches.matchEgamma(),
       Matches.matchInvSqrtPi(),     Matches.matchInvPi(),
@@ -360,7 +357,7 @@ void UseStdNumbersCheck::check(const MatchFinder::MatchResult &Result) {
   };
 
   auto MatchedLiterals =
-      llvm::SmallVector<std::tuple<std::string, double, const Expr *>>{};
+      SmallVector<std::tuple<std::string, double, const Expr *>>{};
 
   const auto &SM = *Result.SourceManager;
   const auto &LO = Result.Context->getLangOpts();
diff --git a/clang-tools-extra/clang-tidy/modernize/UseStdPrintCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseStdPrintCheck.cpp
index e92155c822dc7..710f2e8770495 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseStdPrintCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseStdPrintCheck.cpp
@@ -69,8 +69,8 @@ void UseStdPrintCheck::registerPPCallbacks(const SourceManager &SM,
   this->PP = PP;
 }
 
-static clang::ast_matchers::StatementMatcher unusedReturnValue(
-    const clang::ast_matchers::StatementMatcher &MatchedCallExpr) {
+static StatementMatcher
+unusedReturnValue(const StatementMatcher &MatchedCallExpr) {
   auto UnusedInCompoundStmt =
       compoundStmt(forEach(MatchedCallExpr),
                    // The checker can't currently differentiate between the
diff --git a/clang-tools-extra/clang-tidy/modernize/UseStringViewCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseStringViewCheck.cpp
index 1dc4cc9856549..f5a51c0baba33 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseStringViewCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseStringViewCheck.cpp
@@ -100,8 +100,8 @@ void UseStringViewCheck::check(const MatchFinder::MatchResult &Result) {
   assert(MatchedDecl);
   bool ShouldAKA = false;
   const std::string DesugaredTypeStr =
-      clang::desugarForDiagnostic(
-          *Result.Context, QualType(MatchedDecl->getReturnType()), ShouldAKA)
+      desugarForDiagnostic(*Result.Context,
+                           QualType(MatchedDecl->getReturnType()), ShouldAKA)
           .getAsString();
   const StringRef DestReturnTypeStr = toStringViewTypeStr(DesugaredTypeStr);
 
diff --git a/clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.cpp
index 8dd6bbfa3d2ab..ee1474d9eade1 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.cpp
@@ -100,7 +100,7 @@ enum TransferType : uint8_t {
 /// Matches a Stmt whose parent is a CompoundStmt, and which is directly
 /// following two VarDecls matching the inner matcher.
 AST_MATCHER_P(Stmt, hasPreTwoVarDecl,
-              llvm::SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
+              SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
               InnerMatchers) {
   const DynTypedNodeList Parents = Finder->getASTContext().getParents(Node);
   if (Parents.size() != 1)
@@ -119,7 +119,7 @@ AST_MATCHER_P(Stmt, hasPreTwoVarDecl,
 /// Matches a Stmt whose parent is a CompoundStmt, and which is directly
 /// followed by two VarDecls matching the inner matcher.
 AST_MATCHER_P(Stmt, hasNextTwoVarDecl,
-              llvm::SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
+              SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
               InnerMatchers) {
   const DynTypedNodeList Parents = Finder->getASTContext().getParents(Node);
   if (Parents.size() != 1)
@@ -138,7 +138,7 @@ AST_MATCHER_P(Stmt, hasNextTwoVarDecl,
 /// Matches a CompoundStmt which has two VarDecls matching the inner matcher in
 /// the beginning.
 AST_MATCHER_P(CompoundStmt, hasFirstTwoVarDecl,
-              llvm::SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
+              SmallVector<ast_matchers::internal::Matcher<VarDecl>>,
               InnerMatchers) {
   return matchNVarDeclStartingWith(Node.body_begin(), Node.body_end(),
                                    InnerMatchers, Finder, Builder);
@@ -253,7 +253,7 @@ void UseStructuredBindingCheck::registerMatchers(MatchFinder *Finder) {
                   hasRHS(expr(hasType(PairType))))
                   .bind(StdTieAssignStmtName)),
           hasPreTwoVarDecl(
-              llvm::SmallVector<ast_matchers::internal::Matcher<VarDecl>>{
+              SmallVector<ast_matchers::internal::Matcher<VarDecl>>{
                   varDecl(equalsBoundNode(std::string(FirstVarDeclName))),
                   varDecl(equalsBoundNode(std::string(SecondVarDeclName)))}),
           hasParent(compoundStmt(UnlessFirstVarOrSecondVarIsCapturedByLambda)
@@ -274,7 +274,7 @@ void UseStructuredBindingCheck::registerMatchers(MatchFinder *Finder) {
                                     expr().bind(InitExprName))))
                             .bind(PairDeclName)),
           hasNextTwoVarDecl(
-              llvm::SmallVector<ast_matchers::internal::Matcher<VarDecl>>{
+              SmallVector<ast_matchers::internal::Matcher<VarDecl>>{
                   VarInitWithFirstMember, VarInitWithSecondMember}),
           hasParent(compoundStmt(UnlessFirstVarOrSecondVarIsCapturedByLambda)
                         .bind(ScopeBlockName))),
@@ -293,13 +293,12 @@ void UseStructuredBindingCheck::registerMatchers(MatchFinder *Finder) {
                       hasInitializer(ignoringCopyCtorAndImplicitCast(
                           expr().bind(InitExprName))))
                   .bind(PairDeclName)),
-          hasBody(
-              compoundStmt(
-                  hasFirstTwoVarDecl(llvm::SmallVector<
-                                     ast_matchers::internal::Matcher<VarDecl>>{
-                      VarInitWithFirstMember, VarInitWithSecondMember}),
-                  UnlessFirstVarOrSecondVarIsCapturedByLambda)
-                  .bind(ScopeBlockName)))
+          hasBody(compoundStmt(
+                      hasFirstTwoVarDecl(
+                          SmallVector<ast_matchers::internal::Matcher<VarDecl>>{
+                              VarInitWithFirstMember, VarInitWithSecondMember}),
+                      UnlessFirstVarOrSecondVarIsCapturedByLambda)
+                      .bind(ScopeBlockName)))
           .bind(ForRangeStmtName),
       this);
 }
diff --git a/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
index 4d9b5ee568d80..aaba2d56389f8 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseUsingCheck.cpp
@@ -17,14 +17,16 @@
 #include <string>
 
 using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+
 namespace {
 
-AST_MATCHER(clang::LinkageSpecDecl, isExternCLinkage) {
-  return Node.getLanguage() == clang::LinkageSpecLanguageIDs::C;
+AST_MATCHER(LinkageSpecDecl, isExternCLinkage) {
+  return Node.getLanguage() == LinkageSpecLanguageIDs::C;
 }
-} // namespace
 
-namespace clang::tidy::modernize {
+} // namespace
 
 static constexpr StringRef ExternCDeclName = "extern-c-decl";
 static constexpr StringRef ParentDeclName = "parent-decl";
diff --git a/clang-tools-extra/clang-tidy/mpi/BufferDerefCheck.cpp b/clang-tools-extra/clang-tidy/mpi/BufferDerefCheck.cpp
index 632185295b12f..347059e65f453 100644
--- a/clang-tools-extra/clang-tidy/mpi/BufferDerefCheck.cpp
+++ b/clang-tools-extra/clang-tidy/mpi/BufferDerefCheck.cpp
@@ -83,7 +83,7 @@ void BufferDerefCheck::checkBuffers(ArrayRef<const Type *> BufferTypes,
   for (size_t I = 0; I < BufferTypes.size(); ++I) {
     unsigned IndirectionCount = 0;
     const Type *BufferType = BufferTypes[I];
-    llvm::SmallVector<IndirectionType, 1> Indirections;
+    SmallVector<IndirectionType, 1> Indirections;
 
     // Capture the depth and types of indirections for the passed buffer.
     while (true) {
diff --git a/clang-tools-extra/clang-tidy/objc/AssertEqualsCheck.cpp b/clang-tools-extra/clang-tidy/objc/AssertEqualsCheck.cpp
index a9e6a4b9ea9bb..688dd57cde1d4 100644
--- a/clang-tools-extra/clang-tidy/objc/AssertEqualsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/objc/AssertEqualsCheck.cpp
@@ -46,7 +46,7 @@ void AssertEqualsCheck::check(
       diag(MacroCallsite,
            (Twine("use ") + TargetName + " for comparing objects").str())
           << FixItHint::CreateReplacement(
-                 clang::CharSourceRange::getCharRange(
+                 CharSourceRange::getCharRange(
                      MacroCallsite,
                      MacroCallsite.getLocWithOffset(CurrName.size())),
                  TargetName);
diff --git a/clang-tools-extra/clang-tidy/objc/PropertyDeclarationCheck.cpp b/clang-tools-extra/clang-tidy/objc/PropertyDeclarationCheck.cpp
index e8c49eed190f3..0080a389ce9cb 100644
--- a/clang-tools-extra/clang-tidy/objc/PropertyDeclarationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/objc/PropertyDeclarationCheck.cpp
@@ -40,7 +40,7 @@ static FixItHint generateFixItHint(const ObjCPropertyDecl *Decl,
   size_t Index = 0;
   if (Style == CategoryProperty) {
     const size_t UnderScorePos = Name.find_first_of('_');
-    if (UnderScorePos != llvm::StringRef::npos) {
+    if (UnderScorePos != StringRef::npos) {
       Index = UnderScorePos + 1;
       NewName.replace(0, Index - 1, Name.substr(0, Index - 1).lower());
     }
@@ -50,7 +50,7 @@ static FixItHint generateFixItHint(const ObjCPropertyDecl *Decl,
     if (NewName != Name) {
       return FixItHint::CreateReplacement(
           CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
-          llvm::StringRef(NewName));
+          StringRef(NewName));
     }
   }
   return {};
@@ -78,19 +78,19 @@ static std::string validPropertyNameRegex(bool UsedInMatcher) {
   return StartMatcher + "([a-z]|[A-Z][A-Z0-9])[a-z0-9A-Z]*$";
 }
 
-static bool hasCategoryPropertyPrefix(llvm::StringRef PropertyName) {
+static bool hasCategoryPropertyPrefix(StringRef PropertyName) {
   auto RegexExp =
       llvm::Regex("^[a-zA-Z][a-zA-Z0-9]*_[a-zA-Z0-9][a-zA-Z0-9_]+$");
   return RegexExp.match(PropertyName);
 }
 
-static bool prefixedPropertyNameValid(llvm::StringRef PropertyName) {
+static bool prefixedPropertyNameValid(StringRef PropertyName) {
   const size_t Start = PropertyName.find_first_of('_');
-  assert(Start != llvm::StringRef::npos && Start + 1 < PropertyName.size());
+  assert(Start != StringRef::npos && Start + 1 < PropertyName.size());
   auto Prefix = PropertyName.substr(0, Start);
   if (Prefix.lower() != Prefix)
     return false;
-  auto RegexExp = llvm::Regex(llvm::StringRef(validPropertyNameRegex(false)));
+  auto RegexExp = llvm::Regex(StringRef(validPropertyNameRegex(false)));
   return RegexExp.match(PropertyName.substr(Start + 1));
 }
 
@@ -108,7 +108,7 @@ void PropertyDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
       Result.Nodes.getNodeAs<ObjCPropertyDecl>("property");
   assert(!MatchedDecl->getName().empty());
   auto *DeclContext = MatchedDecl->getDeclContext();
-  auto *CategoryDecl = llvm::dyn_cast<ObjCCategoryDecl>(DeclContext);
+  auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(DeclContext);
 
   if (CategoryDecl != nullptr &&
       hasCategoryPropertyPrefix(MatchedDecl->getName())) {
diff --git a/clang-tools-extra/clang-tidy/openmp/ExceptionEscapeCheck.cpp b/clang-tools-extra/clang-tidy/openmp/ExceptionEscapeCheck.cpp
index 3801fc0f420e5..7d0160c384140 100644
--- a/clang-tools-extra/clang-tidy/openmp/ExceptionEscapeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/openmp/ExceptionEscapeCheck.cpp
@@ -20,7 +20,7 @@ ExceptionEscapeCheck::ExceptionEscapeCheck(StringRef Name,
                                            ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
       RawIgnoredExceptions(Options.get("IgnoredExceptions", "")) {
-  llvm::SmallVector<StringRef, 8> IgnoredExceptionsVec;
+  SmallVector<StringRef, 8> IgnoredExceptionsVec;
 
   llvm::StringSet<> IgnoredExceptions;
   RawIgnoredExceptions.split(IgnoredExceptionsVec, ",", -1, false);
diff --git a/clang-tools-extra/clang-tidy/performance/AvoidEndlCheck.cpp b/clang-tools-extra/clang-tidy/performance/AvoidEndlCheck.cpp
index 0a3596e94e5d8..4433cdf5ac0db 100644
--- a/clang-tools-extra/clang-tidy/performance/AvoidEndlCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/AvoidEndlCheck.cpp
@@ -41,7 +41,7 @@ void AvoidEndlCheck::check(const MatchFinder::MatchResult &Result) {
   // 'std::cout << "Hi" << std::endl;' into
   // 'std::cout << "Hi\n"';
 
-  if (llvm::isa<DeclRefExpr>(Expression)) {
+  if (isa<DeclRefExpr>(Expression)) {
     // Handle the more common streaming '... << std::endl' case
     const CharSourceRange TokenRange =
         CharSourceRange::getTokenRange(Expression->getSourceRange());
@@ -56,7 +56,7 @@ void AvoidEndlCheck::check(const MatchFinder::MatchResult &Result) {
       Diag << FixItHint::CreateReplacement(TokenRange, "'\\n'");
   } else {
     // Handle the less common function call 'std::endl(...)' case
-    const auto *CallExpression = llvm::cast<CallExpr>(Expression);
+    const auto *CallExpression = cast<CallExpr>(Expression);
     assert(CallExpression->getNumArgs() == 1);
 
     StringRef SourceText = Lexer::getSourceText(
diff --git a/clang-tools-extra/clang-tidy/performance/InefficientAlgorithmCheck.cpp b/clang-tools-extra/clang-tidy/performance/InefficientAlgorithmCheck.cpp
index b57fdb2b3ffee..0f896f3816f57 100644
--- a/clang-tools-extra/clang-tidy/performance/InefficientAlgorithmCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/InefficientAlgorithmCheck.cpp
@@ -65,7 +65,7 @@ void InefficientAlgorithmCheck::check(const MatchFinder::MatchResult &Result) {
         Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("IneffContPtr");
     PtrToContainer = true;
   }
-  const llvm::StringRef IneffContName = IneffCont->getName();
+  const StringRef IneffContName = IneffCont->getName();
   const bool Unordered = IneffContName.contains("unordered");
   const bool Maplike = IneffContName.contains("map");
 
diff --git a/clang-tools-extra/clang-tidy/performance/InefficientVectorOperationCheck.cpp b/clang-tools-extra/clang-tidy/performance/InefficientVectorOperationCheck.cpp
index 8029349891327..d073f00878020 100644
--- a/clang-tools-extra/clang-tidy/performance/InefficientVectorOperationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/InefficientVectorOperationCheck.cpp
@@ -229,14 +229,14 @@ void InefficientVectorOperationCheck::check(
   if (VectorAppendCall != nullptr) {
     PartialReserveStmt = ".reserve";
   } else {
-    llvm::StringRef FieldName = ProtoAddFieldCall->getMethodDecl()->getName();
+    StringRef FieldName = ProtoAddFieldCall->getMethodDecl()->getName();
     FieldName.consume_front("add_");
     const std::string MutableFieldName = ("mutable_" + FieldName).str();
     PartialReserveStmt = "." + MutableFieldName +
                          "()->Reserve"; // e.g., ".mutable_xxx()->Reserve"
   }
 
-  const llvm::StringRef VarName = Lexer::getSourceText(
+  const StringRef VarName = Lexer::getSourceText(
       CharSourceRange::getTokenRange(
           AppendCall->getImplicitObjectArgument()->getSourceRange()),
       SM, Context->getLangOpts());
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.cpp
index d4566bc59b7e5..279e83d0f9f71 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.cpp
@@ -16,10 +16,9 @@
 #include "clang/Basic/Diagnostic.h"
 #include <optional>
 
-namespace clang::tidy::performance {
+using namespace clang::ast_matchers;
 
-using namespace ::clang::ast_matchers;
-using llvm::StringRef;
+namespace clang::tidy::performance {
 using utils::decl_ref_expr::allDeclRefExprs;
 using utils::decl_ref_expr::isOnlyUsedAsConst;
 
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.h b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.h
index 89957a5ed09e7..9395a1c01b44f 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.h
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitializationCheck.h
@@ -42,7 +42,7 @@ class UnnecessaryCopyInitializationCheck : public ClangTidyCheck {
     const VarDecl &Var;
     const Stmt &BlockStmt;
     const DeclStmt &VarDeclStmt;
-    clang::ASTContext &ASTCtx;
+    ASTContext &ASTCtx;
     const bool IssueFix;
     const bool IsVarUnused;
     const bool IsVarOnlyUsedAsConst;
diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
index ffb2a81b862f6..f126dbe678238 100644
--- a/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp
@@ -149,7 +149,7 @@ void UnnecessaryValueParamCheck::handleConstRefFix(const FunctionDecl &Function,
   // 1. the ParmVarDecl is in a macro, since we cannot place them correctly
   // 2. the function is virtual as it might break overrides
   // 3. the function is an explicit template/ specialization.
-  const auto *Method = llvm::dyn_cast<CXXMethodDecl>(&Function);
+  const auto *Method = dyn_cast<CXXMethodDecl>(&Function);
   if (Param.getBeginLoc().isMacroID() || (Method && Method->isVirtual()) ||
       Function.getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
     return;
diff --git a/clang-tools-extra/clang-tidy/portability/AvoidPragmaOnceCheck.cpp b/clang-tools-extra/clang-tidy/portability/AvoidPragmaOnceCheck.cpp
index 902579f1bf9e9..bfcc52d3c8c3f 100644
--- a/clang-tools-extra/clang-tidy/portability/AvoidPragmaOnceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/portability/AvoidPragmaOnceCheck.cpp
@@ -23,7 +23,7 @@ class PragmaOnceCallbacks : public PPCallbacks {
       : Check(Check), SM(SM) {}
   void PragmaDirective(SourceLocation Loc,
                        PragmaIntroducerKind Introducer) override {
-    auto Str = llvm::StringRef(SM.getCharacterData(Loc));
+    auto Str = StringRef(SM.getCharacterData(Loc));
     if (!Str.consume_front("#"))
       return;
     Str = Str.trim();
diff --git a/clang-tools-extra/clang-tidy/portability/RestrictSystemIncludesCheck.h b/clang-tools-extra/clang-tidy/portability/RestrictSystemIncludesCheck.h
index d66149aceae91..6a68c58bb60a5 100644
--- a/clang-tools-extra/clang-tidy/portability/RestrictSystemIncludesCheck.h
+++ b/clang-tools-extra/clang-tidy/portability/RestrictSystemIncludesCheck.h
@@ -70,7 +70,7 @@ class RestrictedIncludesPPCallbacks : public PPCallbacks {
     bool IsInMainFile;       // Whether or not the include is in the main file
   };
 
-  using FileIncludes = llvm::SmallVector<IncludeDirective, 8>;
+  using FileIncludes = SmallVector<IncludeDirective, 8>;
   llvm::SmallDenseMap<FileID, FileIncludes> IncludeDirectives;
 
   RestrictSystemIncludesCheck &Check;
diff --git a/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.h b/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.h
index addcecbcb9370..2553a0c76a96c 100644
--- a/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.h
+++ b/clang-tools-extra/clang-tidy/portability/SIMDIntrinsicsCheck.h
@@ -31,7 +31,7 @@ class SIMDIntrinsicsCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  llvm::SmallString<32> Std;
+  SmallString<32> Std;
   const bool Suggest;
 };
 
diff --git a/clang-tools-extra/clang-tidy/readability/ConstReturnTypeCheck.cpp b/clang-tools-extra/clang-tidy/readability/ConstReturnTypeCheck.cpp
index cfdf0e9c4a331..405174ee0209b 100644
--- a/clang-tools-extra/clang-tidy/readability/ConstReturnTypeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ConstReturnTypeCheck.cpp
@@ -60,16 +60,16 @@ struct CheckResult {
   CharSourceRange ConstRange;
 
   // FixItHints associated with the definition being checked.
-  llvm::SmallVector<clang::FixItHint, 4> Hints;
+  SmallVector<FixItHint, 4> Hints;
 
   // Locations of any declarations that could not be fixed.
-  llvm::SmallVector<clang::SourceLocation, 4> DeclLocs;
+  SmallVector<SourceLocation, 4> DeclLocs;
 };
 
 } // namespace
 
 // Does the actual work of the check.
-static CheckResult checkDef(const clang::FunctionDecl *Def,
+static CheckResult checkDef(const FunctionDecl *Def,
                             const MatchFinder::MatchResult &MatchResult) {
   CheckResult Result;
   std::optional<Token> Tok = findConstToRemove(Def, MatchResult);
diff --git a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
index 780a965778551..7c777638e0e59 100644
--- a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.cpp
@@ -94,7 +94,7 @@ AST_MATCHER(QualType, isIntegralType) {
 }
 
 AST_MATCHER_P(UserDefinedLiteral, hasLiteral,
-              clang::ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
+              ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
   const UserDefinedLiteral::LiteralOperatorKind LOK =
       Node.getLiteralOperatorKind();
   if (LOK == UserDefinedLiteral::LOK_Template ||
@@ -107,8 +107,7 @@ AST_MATCHER_P(UserDefinedLiteral, hasLiteral,
 }
 
 AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl,
-              clang::ast_matchers::internal::Matcher<CXXMethodDecl>,
-              InnerMatcher) {
+              ast_matchers::internal::Matcher<CXXMethodDecl>, InnerMatcher) {
   return InnerMatcher.matches(*Node.getCanonicalDecl(), Finder, Builder);
 }
 
@@ -300,9 +299,9 @@ void ContainerSizeEmptyCheck::check(const MatchFinder::MatchResult &Result) {
                                         ReplacementText);
   } else if (BinaryOp) { // Determine the correct transformation.
     const auto *LiteralLHS =
-        llvm::dyn_cast<IntegerLiteral>(BinaryOp->getLHS()->IgnoreImpCasts());
+        dyn_cast<IntegerLiteral>(BinaryOp->getLHS()->IgnoreImpCasts());
     const auto *LiteralRHS =
-        llvm::dyn_cast<IntegerLiteral>(BinaryOp->getRHS()->IgnoreImpCasts());
+        dyn_cast<IntegerLiteral>(BinaryOp->getRHS()->IgnoreImpCasts());
     const bool ContainerIsLHS = !LiteralLHS;
 
     uint64_t Value = 0;
diff --git a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.h b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.h
index 35ef18430378b..6d984d29ada66 100644
--- a/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.h
@@ -37,7 +37,7 @@ class ContainerSizeEmptyCheck : public ClangTidyCheck {
   }
 
 private:
-  std::vector<llvm::StringRef> ExcludedComparisonTypes;
+  std::vector<StringRef> ExcludedComparisonTypes;
 };
 
 } // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/ConvertMemberFunctionsToStaticCheck.cpp b/clang-tools-extra/clang-tidy/readability/ConvertMemberFunctionsToStaticCheck.cpp
index 0ca65d3663e53..4bca9686e94e1 100644
--- a/clang-tools-extra/clang-tidy/readability/ConvertMemberFunctionsToStaticCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ConvertMemberFunctionsToStaticCheck.cpp
@@ -42,8 +42,8 @@ AST_MATCHER(CXXMethodDecl, isDependentContext) {
 
 AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {
   const ASTContext &Ctxt = Finder->getASTContext();
-  return clang::Lexer::makeFileCharRange(
-             clang::CharSourceRange::getCharRange(
+  return Lexer::makeFileCharRange(
+             CharSourceRange::getCharRange(
                  Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),
              Ctxt.getSourceManager(), Ctxt.getLangOpts())
       .isInvalid();
diff --git a/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp b/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
index 7e93d619e2a9f..a128f788d6bde 100644
--- a/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
@@ -93,7 +93,7 @@ static const DeclRefExpr *checkInitDeclUsageInElse(const IfStmt *If) {
     assert(isa<VarDecl>(InitDecl) && "SingleDecl must be a VarDecl");
     return findUsage(If->getElse(), InitDecl->getID());
   }
-  llvm::SmallVector<int64_t, 4> DeclIdentifiers;
+  SmallVector<int64_t, 4> DeclIdentifiers;
   for (const Decl *ChildDecl : InitDeclStmt->decls()) {
     assert(isa<VarDecl>(ChildDecl) && "Init Decls must be a VarDecl");
     DeclIdentifiers.push_back(ChildDecl->getID());
@@ -135,7 +135,7 @@ static void removeElseAndBrackets(DiagnosticBuilder &Diag, ASTContext &Context,
         Remap(LBrace).getLocWithOffset(TokLen(LBrace) + 1);
     const SourceLocation RangeEnd = Remap(RBrace).getLocWithOffset(-1);
 
-    const llvm::StringRef Repl = Lexer::getSourceText(
+    const StringRef Repl = Lexer::getSourceText(
         CharSourceRange::getTokenRange(RangeStart, RangeEnd),
         Context.getSourceManager(), Context.getLangOpts());
     Diag << tooling::fixit::createReplacement(CS->getSourceRange(), Repl);
@@ -143,7 +143,7 @@ static void removeElseAndBrackets(DiagnosticBuilder &Diag, ASTContext &Context,
     const SourceLocation ElseExpandedLoc = Remap(ElseLoc);
     const SourceLocation EndLoc = Remap(Else->getEndLoc());
 
-    const llvm::StringRef Repl = Lexer::getSourceText(
+    const StringRef Repl = Lexer::getSourceText(
         CharSourceRange::getTokenRange(
             ElseExpandedLoc.getLocWithOffset(TokLen(ElseLoc) + 1), EndLoc),
         Context.getSourceManager(), Context.getLangOpts());
@@ -276,7 +276,7 @@ void ElseAfterReturnCheck::check(const MatchFinder::MatchResult &Result) {
         Diag << tooling::fixit::createReplacement(
                     SourceRange(If->getIfLoc()),
                     (tooling::fixit::getText(*If->getInit(), *Result.Context) +
-                     llvm::StringRef("\n"))
+                     StringRef("\n"))
                         .str())
              << tooling::fixit::createRemoval(If->getInit()->getSourceRange());
       }
@@ -284,7 +284,7 @@ void ElseAfterReturnCheck::check(const MatchFinder::MatchResult &Result) {
       const VarDecl *VDecl = If->getConditionVariable();
       const std::string Repl =
           (tooling::fixit::getText(*VDeclStmt, *Result.Context) +
-           llvm::StringRef(";\n") +
+           StringRef(";\n") +
            tooling::fixit::getText(If->getIfLoc(), *Result.Context))
               .str();
       Diag << tooling::fixit::createReplacement(SourceRange(If->getIfLoc()),
diff --git a/clang-tools-extra/clang-tidy/readability/EnumInitialValueCheck.cpp b/clang-tools-extra/clang-tidy/readability/EnumInitialValueCheck.cpp
index d99143c875729..4612d94f3663b 100644
--- a/clang-tools-extra/clang-tidy/readability/EnumInitialValueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/EnumInitialValueCheck.cpp
@@ -181,7 +181,7 @@ void EnumInitialValueCheck::check(const MatchFinder::MatchResult &Result) {
               ECD->getLocation(), 0, *Result.SourceManager, getLangOpts());
           if (EndLoc.isMacroID())
             continue;
-          llvm::SmallString<8> Str{" = "};
+          SmallString<8> Str{" = "};
           ECD->getInitVal().toString(Str);
           Diag << FixItHint::CreateInsertion(EndLoc, Str);
         }
diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
index 83fc3727cb5c8..17fbfcf1fb181 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -242,8 +242,7 @@ IdentifierNamingCheck::NamingStyle::NamingStyle(
     : Case(Case), Prefix(Prefix), Suffix(Suffix),
       IgnoredRegexpStr(IgnoredRegexpStr), HPType(HPType) {
   if (!IgnoredRegexpStr.empty()) {
-    IgnoredRegexp =
-        llvm::Regex(llvm::SmallString<128>({"^", IgnoredRegexpStr, "$"}));
+    IgnoredRegexp = llvm::Regex(SmallString<128>({"^", IgnoredRegexpStr, "$"}));
     if (!IgnoredRegexp.isValid())
       llvm::errs() << "Invalid IgnoredRegexp regular expression: "
                    << IgnoredRegexpStr;
@@ -634,7 +633,7 @@ std::string IdentifierNamingCheck::HungarianNotation::getDataTypePrefix(
   return PrefixStr;
 }
 
-llvm::StringRef IdentifierNamingCheck::HungarianNotation::getClassPrefix(
+StringRef IdentifierNamingCheck::HungarianNotation::getClassPrefix(
     const CXXRecordDecl *CRD,
     const IdentifierNamingCheck::HungarianNotationOption &HNOption) const {
   if (CRD->isUnion())
@@ -1440,7 +1439,7 @@ IdentifierNamingCheck::getStyleForFile(StringRef FileName) const {
   if (Iter != NamingStylesCache.end())
     return Iter->getValue();
 
-  const llvm::StringRef CheckName = getID();
+  const StringRef CheckName = getID();
   ClangTidyOptions Options = Context->getOptionsForFile(RealFileName);
   if (Options.Checks && GlobList(*Options.Checks).contains(CheckName)) {
     auto It = NamingStylesCache.try_emplace(
diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
index b016556cc2ab8..0afc7e2246816 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.h
@@ -116,7 +116,7 @@ class IdentifierNamingCheck final : public RenamerClangTidyCheck {
         StringRef TypeName, const NamedDecl *ND,
         const IdentifierNamingCheck::HungarianNotationOption &HNOption) const;
 
-    llvm::StringRef getClassPrefix(
+    StringRef getClassPrefix(
         const CXXRecordDecl *CRD,
         const IdentifierNamingCheck::HungarianNotationOption &HNOption) const;
 
diff --git a/clang-tools-extra/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp b/clang-tools-extra/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
index e406532d78a01..eb7bb6f14e382 100644
--- a/clang-tools-extra/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
@@ -39,7 +39,7 @@ struct DifferingParamInfo {
   bool GenerateFixItHint;
 };
 
-using DifferingParamsContainer = llvm::SmallVector<DifferingParamInfo, 10>;
+using DifferingParamsContainer = SmallVector<DifferingParamInfo, 10>;
 
 struct InconsistentDeclarationInfo {
   InconsistentDeclarationInfo(SourceLocation DeclarationLocation,
@@ -52,7 +52,7 @@ struct InconsistentDeclarationInfo {
 };
 
 using InconsistentDeclarationsContainer =
-    llvm::SmallVector<InconsistentDeclarationInfo, 2>;
+    SmallVector<InconsistentDeclarationInfo, 2>;
 
 } // namespace
 
@@ -195,7 +195,7 @@ getParameterSourceDeclaration(const FunctionDecl *OriginalDeclaration) {
 static std::string joinParameterNames(
     const DifferingParamsContainer &DifferingParams,
     llvm::function_ref<StringRef(const DifferingParamInfo &)> ChooseParamName) {
-  llvm::SmallString<40> Str;
+  SmallString<40> Str;
   bool First = true;
   for (const DifferingParamInfo &ParamInfo : DifferingParams) {
     if (First)
diff --git a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
index fb4690bd8c76b..acf9503f265fe 100644
--- a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
@@ -232,7 +232,7 @@ bool MagicNumbersCheck::isSyntheticValue(const SourceManager *SourceManager,
 }
 
 bool MagicNumbersCheck::isBitFieldWidth(
-    const clang::ast_matchers::MatchFinder::MatchResult &Result,
+    const ast_matchers::MatchFinder::MatchResult &Result,
     const IntegerLiteral &Literal) const {
   return IgnoreBitFieldsWidths &&
          llvm::any_of(Result.Context->getParents(Literal),
@@ -242,8 +242,8 @@ bool MagicNumbersCheck::isBitFieldWidth(
 }
 
 bool MagicNumbersCheck::isUserDefinedLiteral(
-    const clang::ast_matchers::MatchFinder::MatchResult &Result,
-    const clang::Expr &Literal) const {
+    const ast_matchers::MatchFinder::MatchResult &Result,
+    const Expr &Literal) const {
   const DynTypedNodeList Parents = Result.Context->getParents(Literal);
   if (Parents.empty())
     return false;
diff --git a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h
index 53954535ebe86..ca64880c030cf 100644
--- a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h
@@ -28,31 +28,29 @@ class MagicNumbersCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  bool isConstant(const clang::ast_matchers::MatchFinder::MatchResult &Result,
-                  const clang::Expr &ExprResult) const;
+  bool isConstant(const ast_matchers::MatchFinder::MatchResult &Result,
+                  const Expr &ExprResult) const;
 
   bool isIgnoredValue(const IntegerLiteral *Literal) const;
   bool isIgnoredValue(const FloatingLiteral *Literal) const;
 
-  bool isSyntheticValue(const clang::SourceManager *,
-                        const FloatingLiteral *) const {
+  bool isSyntheticValue(const SourceManager *, const FloatingLiteral *) const {
     return false;
   }
-  bool isSyntheticValue(const clang::SourceManager *SourceManager,
+  bool isSyntheticValue(const SourceManager *SourceManager,
                         const IntegerLiteral *Literal) const;
 
-  bool isBitFieldWidth(const clang::ast_matchers::MatchFinder::MatchResult &,
+  bool isBitFieldWidth(const ast_matchers::MatchFinder::MatchResult &,
                        const FloatingLiteral &) const {
     return false;
   }
 
-  bool
-  isBitFieldWidth(const clang::ast_matchers::MatchFinder::MatchResult &Result,
-                  const IntegerLiteral &Literal) const;
+  bool isBitFieldWidth(const ast_matchers::MatchFinder::MatchResult &Result,
+                       const IntegerLiteral &Literal) const;
 
-  bool isUserDefinedLiteral(
-      const clang::ast_matchers::MatchFinder::MatchResult &Result,
-      const clang::Expr &Literal) const;
+  bool
+  isUserDefinedLiteral(const ast_matchers::MatchFinder::MatchResult &Result,
+                       const Expr &Literal) const;
 
   template <typename L>
   void checkBoundMatch(const ast_matchers::MatchFinder::MatchResult &Result,
@@ -103,11 +101,11 @@ class MagicNumbersCheck : public ClangTidyCheck {
   constexpr static llvm::APFloat::roundingMode DefaultRoundingMode =
       llvm::APFloat::rmNearestTiesToEven;
 
-  llvm::SmallVector<int64_t, SensibleNumberOfMagicValueExceptions>
+  SmallVector<int64_t, SensibleNumberOfMagicValueExceptions>
       IgnoredIntegerValues;
-  llvm::SmallVector<float, SensibleNumberOfMagicValueExceptions>
+  SmallVector<float, SensibleNumberOfMagicValueExceptions>
       IgnoredFloatingPointValues;
-  llvm::SmallVector<double, SensibleNumberOfMagicValueExceptions>
+  SmallVector<double, SensibleNumberOfMagicValueExceptions>
       IgnoredDoublePointValues;
 };
 
diff --git a/clang-tools-extra/clang-tidy/readability/MakeMemberFunctionConstCheck.cpp b/clang-tools-extra/clang-tidy/readability/MakeMemberFunctionConstCheck.cpp
index 7564806464d34..e8875d014fe21 100644
--- a/clang-tools-extra/clang-tidy/readability/MakeMemberFunctionConstCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/MakeMemberFunctionConstCheck.cpp
@@ -37,8 +37,8 @@ AST_MATCHER(CXXMethodDecl, isDependentContext) {
 
 AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {
   const ASTContext &Ctxt = Finder->getASTContext();
-  return clang::Lexer::makeFileCharRange(
-             clang::CharSourceRange::getCharRange(
+  return Lexer::makeFileCharRange(
+             CharSourceRange::getCharRange(
                  Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),
              Ctxt.getSourceManager(), Ctxt.getLangOpts())
       .isInvalid();
diff --git a/clang-tools-extra/clang-tidy/readability/MathMissingParenthesesCheck.cpp b/clang-tools-extra/clang-tidy/readability/MathMissingParenthesesCheck.cpp
index 1d52aaa6de008..a9c1b6a688d98 100644
--- a/clang-tools-extra/clang-tidy/readability/MathMissingParenthesesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/MathMissingParenthesesCheck.cpp
@@ -49,9 +49,8 @@ static int getPrecedence(const BinaryOperator *BinOp) {
   }
 }
 static void addParentheses(const Expr *E, const BinaryOperator *ParentBinOp,
-                           ClangTidyCheck *Check,
-                           const clang::SourceManager &SM,
-                           const clang::LangOptions &LangOpts) {
+                           ClangTidyCheck *Check, const SourceManager &SM,
+                           const LangOptions &LangOpts) {
   if (const auto *Paren = dyn_cast<ParenExpr>(E)) {
     addParentheses(Paren->getSubExpr()->IgnoreImpCasts(), nullptr, Check, SM,
                    LangOpts);
@@ -67,9 +66,9 @@ static void addParentheses(const Expr *E, const BinaryOperator *ParentBinOp,
 
   if (ParentBinOp != nullptr && Precedence1 != Precedence2 && Precedence1 > 0 &&
       Precedence2 > 0) {
-    const clang::SourceLocation StartLoc = BinOp->getBeginLoc();
-    const clang::SourceLocation EndLoc =
-        clang::Lexer::getLocForEndOfToken(BinOp->getEndLoc(), 0, SM, LangOpts);
+    const SourceLocation StartLoc = BinOp->getBeginLoc();
+    const SourceLocation EndLoc =
+        Lexer::getLocForEndOfToken(BinOp->getEndLoc(), 0, SM, LangOpts);
 
     auto Diag =
         Check->diag(StartLoc,
@@ -95,7 +94,7 @@ void MathMissingParenthesesCheck::check(
     const MatchFinder::MatchResult &Result) {
   const auto *BinOp = Result.Nodes.getNodeAs<BinaryOperator>("binOp");
   const SourceManager &SM = *Result.SourceManager;
-  const clang::LangOptions &LO = Result.Context->getLangOpts();
+  const LangOptions &LO = Result.Context->getLangOpts();
   addParentheses(BinOp, nullptr, this, SM, LO);
 }
 
diff --git a/clang-tools-extra/clang-tidy/readability/NamedParameterCheck.cpp b/clang-tools-extra/clang-tidy/readability/NamedParameterCheck.cpp
index 46f11027c970e..c457d682a1787 100644
--- a/clang-tools-extra/clang-tidy/readability/NamedParameterCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/NamedParameterCheck.cpp
@@ -67,7 +67,7 @@ void NamedParameterCheck::check(const MatchFinder::MatchResult &Result) {
       continue;
 
     // Skip gmock testing::Unused parameters.
-    if (const auto *Typedef = Parm->getType()->getAs<clang::TypedefType>())
+    if (const auto *Typedef = Parm->getType()->getAs<TypedefType>())
       if (Typedef->getDecl()->getQualifiedNameAsString() == "testing::Unused")
         continue;
 
diff --git a/clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h b/clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h
index fe5736fad0d15..68902428e9bab 100644
--- a/clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h
@@ -35,7 +35,7 @@ class NamespaceCommentCheck : public ClangTidyCheck {
   const unsigned ShortNamespaceLines;
   const unsigned SpacesBeforeComments;
   const bool AllowOmittingNamespaceComments;
-  llvm::SmallVector<SourceLocation, 4> Ends;
+  SmallVector<SourceLocation, 4> Ends;
 };
 
 } // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp
index db1fb0aa3c834..82fba056f1de2 100644
--- a/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp
@@ -36,8 +36,7 @@ static StringRef getOperatorSpelling(SourceLocation Loc, ASTContext &Context) {
 namespace {
 
 AST_MATCHER_P2(BinaryOperator, hasInvalidBinaryOperatorRepresentation,
-               BinaryOperatorKind, Kind, llvm::StringRef,
-               ExpectedRepresentation) {
+               BinaryOperatorKind, Kind, StringRef, ExpectedRepresentation) {
   if (Node.getOpcode() != Kind || ExpectedRepresentation.empty())
     return false;
 
@@ -47,8 +46,7 @@ AST_MATCHER_P2(BinaryOperator, hasInvalidBinaryOperatorRepresentation,
 }
 
 AST_MATCHER_P2(UnaryOperator, hasInvalidUnaryOperatorRepresentation,
-               UnaryOperatorKind, Kind, llvm::StringRef,
-               ExpectedRepresentation) {
+               UnaryOperatorKind, Kind, StringRef, ExpectedRepresentation) {
   if (Node.getOpcode() != Kind || ExpectedRepresentation.empty())
     return false;
 
@@ -58,7 +56,7 @@ AST_MATCHER_P2(UnaryOperator, hasInvalidUnaryOperatorRepresentation,
 }
 
 AST_MATCHER_P2(CXXOperatorCallExpr, hasInvalidOverloadedOperatorRepresentation,
-               OverloadedOperatorKind, Kind, llvm::StringRef,
+               OverloadedOperatorKind, Kind, StringRef,
                ExpectedRepresentation) {
   if (Node.getOperator() != Kind || ExpectedRepresentation.empty())
     return false;
@@ -70,10 +68,10 @@ AST_MATCHER_P2(CXXOperatorCallExpr, hasInvalidOverloadedOperatorRepresentation,
 
 } // namespace
 
-constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 2U>
-    UnaryRepresentation{{{"!", "not"}, {"~", "compl"}}};
+constexpr std::array<std::pair<StringRef, StringRef>, 2U> UnaryRepresentation{
+    {{"!", "not"}, {"~", "compl"}}};
 
-constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 9U>
+constexpr std::array<std::pair<StringRef, StringRef>, 9U>
     OperatorsRepresentation{{{"&&", "and"},
                              {"||", "or"},
                              {"^", "xor"},
@@ -84,7 +82,7 @@ constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 9U>
                              {"!=", "not_eq"},
                              {"^=", "xor_eq"}}};
 
-static llvm::StringRef translate(llvm::StringRef Value) {
+static StringRef translate(StringRef Value) {
   for (const auto &[Traditional, Alternative] : UnaryRepresentation) {
     if (Value == Traditional)
       return Alternative;
@@ -101,16 +99,16 @@ static llvm::StringRef translate(llvm::StringRef Value) {
   return {};
 }
 
-static bool isNotOperatorStr(llvm::StringRef Value) {
+static bool isNotOperatorStr(StringRef Value) {
   return translate(Value).empty();
 }
 
 static bool isSeparator(char C) noexcept {
-  constexpr llvm::StringRef Separators(" \t\r\n\0()<>{};,");
+  constexpr StringRef Separators(" \t\r\n\0()<>{};,");
   return Separators.contains(C);
 }
 
-static bool needEscaping(llvm::StringRef Operator) {
+static bool needEscaping(StringRef Operator) {
   switch (Operator[0]) {
   case '&':
   case '|':
@@ -123,9 +121,9 @@ static bool needEscaping(llvm::StringRef Operator) {
   }
 }
 
-static llvm::StringRef
-getRepresentation(const std::vector<llvm::StringRef> &Config,
-                  llvm::StringRef Traditional, llvm::StringRef Alternative) {
+static StringRef getRepresentation(const std::vector<StringRef> &Config,
+                                   StringRef Traditional,
+                                   StringRef Alternative) {
   if (llvm::is_contained(Config, Traditional))
     return Traditional;
   if (llvm::is_contained(Config, Alternative))
@@ -134,7 +132,7 @@ getRepresentation(const std::vector<llvm::StringRef> &Config,
 }
 
 template <typename T>
-static bool isAnyOperatorEnabled(const std::vector<llvm::StringRef> &Config,
+static bool isAnyOperatorEnabled(const std::vector<StringRef> &Config,
                                  const T &Operators) {
   return llvm::any_of(Operators, [&](const auto &Op) {
     return !getRepresentation(Config, Op.first, Op.second).empty();
diff --git a/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.h b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.h
index 2ce8ac0161bf9..1bbe5712aed02 100644
--- a/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.h
@@ -33,8 +33,8 @@ class OperatorsRepresentationCheck : public ClangTidyCheck {
   void registerUnaryOperatorMatcher(ast_matchers::MatchFinder *Finder);
   void registerOverloadedOperatorMatcher(ast_matchers::MatchFinder *Finder);
 
-  std::vector<llvm::StringRef> BinaryOperators;
-  std::vector<llvm::StringRef> OverloadedOperators;
+  std::vector<StringRef> BinaryOperators;
+  std::vector<StringRef> OverloadedOperators;
 };
 
 } // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp b/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
index afb8c800a70e2..4ba80541ad565 100644
--- a/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/QualifiedAutoCheck.cpp
@@ -120,7 +120,7 @@ void QualifiedAutoCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
 void QualifiedAutoCheck::registerMatchers(MatchFinder *Finder) {
   auto ExplicitSingleVarDecl =
       [](const ast_matchers::internal::Matcher<VarDecl> &InnerMatcher,
-         llvm::StringRef ID) {
+         StringRef ID) {
         return declStmt(
             unless(isInTemplateInstantiation()),
             hasSingleDecl(
@@ -128,7 +128,7 @@ void QualifiedAutoCheck::registerMatchers(MatchFinder *Finder) {
       };
   auto ExplicitSingleVarDeclInTemplate =
       [](const ast_matchers::internal::Matcher<VarDecl> &InnerMatcher,
-         llvm::StringRef ID) {
+         StringRef ID) {
         return declStmt(
             isInTemplateInstantiation(),
             hasSingleDecl(
@@ -197,7 +197,7 @@ void QualifiedAutoCheck::check(const MatchFinder::MatchResult &Result) {
       return;
     }
 
-    llvm::SmallVector<SourceRange, 4> RemoveQualifiersRange;
+    SmallVector<SourceRange, 4> RemoveQualifiersRange;
     auto CheckQualifier = [&](bool IsPresent, Qualifier Qual) {
       if (IsPresent) {
         std::optional<Token> Token = findQualToken(Var, Qual, Result);
diff --git a/clang-tools-extra/clang-tidy/readability/ReferenceToConstructedTemporaryCheck.cpp b/clang-tools-extra/clang-tidy/readability/ReferenceToConstructedTemporaryCheck.cpp
index 3700bdce2ba4e..7a74651b454b3 100644
--- a/clang-tools-extra/clang-tidy/readability/ReferenceToConstructedTemporaryCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ReferenceToConstructedTemporaryCheck.cpp
@@ -32,13 +32,13 @@ struct NotExtendedByDeclBoundToPredicate {
   }
 
   StringRef ID;
-  ::clang::DynTypedNode Node;
+  DynTypedNode Node;
 };
 
 AST_MATCHER_P(MaterializeTemporaryExpr, isExtendedByDeclBoundTo, StringRef,
               ID) {
-  const NotExtendedByDeclBoundToPredicate Predicate{
-      ID, ::clang::DynTypedNode::create(Node)};
+  const NotExtendedByDeclBoundToPredicate Predicate{ID,
+                                                    DynTypedNode::create(Node)};
   return Builder->removeBindings(Predicate);
 }
 
diff --git a/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.cpp b/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.cpp
index 040f6fb8c843c..b0e95c0afc184 100644
--- a/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/SimplifyBooleanExprCheck.cpp
@@ -806,7 +806,7 @@ void SimplifyBooleanExprCheck::replaceWithAssignment(const ASTContext &Context,
 }
 
 /// Swaps a \c BinaryOperator opcode from `&&` to `||` or vice-versa.
-static bool flipDemorganOperator(llvm::SmallVectorImpl<FixItHint> &Output,
+static bool flipDemorganOperator(SmallVectorImpl<FixItHint> &Output,
                                  const BinaryOperator *BO) {
   assert(BO->isLogicalOp());
   if (BO->getOperatorLoc().isMacroID())
diff --git a/clang-tools-extra/clang-tidy/readability/UseStdMinMaxCheck.cpp b/clang-tools-extra/clang-tidy/readability/UseStdMinMaxCheck.cpp
index 6255bbd9e5778..d8145700f5a9d 100644
--- a/clang-tools-extra/clang-tidy/readability/UseStdMinMaxCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/UseStdMinMaxCheck.cpp
@@ -25,7 +25,7 @@ AST_MATCHER(IfStmt, isIfInMacro) {
 
 } // namespace
 
-static const llvm::StringRef AlgorithmHeader("<algorithm>");
+static constexpr StringRef AlgorithmHeader = "<algorithm>";
 
 static bool minCondition(const BinaryOperator::Opcode Op, const Expr *CondLhs,
                          const Expr *CondRhs, const Expr *AssignLhs,
@@ -85,9 +85,9 @@ static QualType getReplacementCastType(const Expr *CondLhs, const Expr *CondRhs,
       RhsType.getCanonicalType().getNonReferenceType().getUnqualifiedType();
   QualType GlobalImplicitCastType;
   if (LhsCanonicalType != RhsCanonicalType) {
-    if (llvm::isa<IntegerLiteral>(CondRhs))
+    if (isa<IntegerLiteral>(CondRhs))
       GlobalImplicitCastType = getNonTemplateAlias(LhsType);
-    else if (llvm::isa<IntegerLiteral>(CondLhs))
+    else if (isa<IntegerLiteral>(CondLhs))
       GlobalImplicitCastType = getNonTemplateAlias(RhsType);
     else
       GlobalImplicitCastType = getNonTemplateAlias(ComparedType);
@@ -100,11 +100,11 @@ createReplacement(const Expr *CondLhs, const Expr *CondRhs,
                   const Expr *AssignLhs, const SourceManager &Source,
                   const LangOptions &LO, StringRef FunctionName,
                   const BinaryOperator *BO, StringRef Comment = "") {
-  const llvm::StringRef CondLhsStr = Lexer::getSourceText(
+  const StringRef CondLhsStr = Lexer::getSourceText(
       Source.getExpansionRange(CondLhs->getSourceRange()), Source, LO);
-  const llvm::StringRef CondRhsStr = Lexer::getSourceText(
+  const StringRef CondRhsStr = Lexer::getSourceText(
       Source.getExpansionRange(CondRhs->getSourceRange()), Source, LO);
-  const llvm::StringRef AssignLhsStr = Lexer::getSourceText(
+  const StringRef AssignLhsStr = Lexer::getSourceText(
       Source.getExpansionRange(AssignLhs->getSourceRange()), Source, LO);
 
   const QualType GlobalImplicitCastType =
@@ -159,21 +159,21 @@ void UseStdMinMaxCheck::registerPPCallbacks(const SourceManager &SM,
 
 void UseStdMinMaxCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
-  const clang::LangOptions &LO = Result.Context->getLangOpts();
+  const LangOptions &LO = Result.Context->getLangOpts();
   const auto *CondLhs = Result.Nodes.getNodeAs<Expr>("CondLhs");
   const auto *CondRhs = Result.Nodes.getNodeAs<Expr>("CondRhs");
   const auto *AssignLhs = Result.Nodes.getNodeAs<Expr>("AssignLhs");
   const auto *AssignRhs = Result.Nodes.getNodeAs<Expr>("AssignRhs");
   const auto *BinaryOp = Result.Nodes.getNodeAs<BinaryOperator>("binaryOp");
-  const clang::BinaryOperatorKind BinaryOpcode = BinaryOp->getOpcode();
+  const BinaryOperatorKind BinaryOpcode = BinaryOp->getOpcode();
   const SourceLocation IfLocation = If->getIfLoc();
   const SourceLocation ThenLocation = If->getEndLoc();
 
-  auto ReplaceAndDiagnose = [&](const llvm::StringRef FunctionName) {
+  auto ReplaceAndDiagnose = [&](const StringRef FunctionName) {
     const SourceManager &Source = *Result.SourceManager;
-    llvm::SmallString<64> Comment;
+    SmallString<64> Comment;
 
-    const auto AppendNormalized = [&](llvm::StringRef Text) {
+    const auto AppendNormalized = [&](StringRef Text) {
       Text = Text.ltrim();
       if (!Text.empty()) {
         if (!Comment.empty())
@@ -210,16 +210,13 @@ void UseStdMinMaxCheck::check(const MatchFinder::MatchResult &Result) {
       // Captures:
       // if (cond) { x = y; // Comment C }
       // if (cond) { x = y; /* Comment C */ }
-      llvm::StringRef PostInner =
-          GetSourceText(Inner->getEndLoc(), CS->getEndLoc());
+      StringRef PostInner = GetSourceText(Inner->getEndLoc(), CS->getEndLoc());
 
       // Strip the trailing semicolon to avoid fixes like:
       // x = std::min(x, y);; // comment
       const size_t Semi = PostInner.find(';');
-      if (Semi != llvm::StringRef::npos &&
-          PostInner.take_front(Semi).trim().empty()) {
+      if (Semi != StringRef::npos && PostInner.take_front(Semi).trim().empty())
         PostInner = PostInner.drop_front(Semi + 1);
-      }
       AppendNormalized(PostInner);
     }
 
diff --git a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
index f2115522ca40d..c2157f29e103e 100644
--- a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
+++ b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
@@ -532,7 +532,7 @@ static bool verifyChecks(const StringSet<> &AllChecks, StringRef CheckGlob,
         llvm::raw_ostream &Output =
             llvm::WithColor::warning(llvm::errs(), Source)
             << "unknown check '" << Item.Text << '\'';
-        const llvm::StringRef Closest = closest(Item.Text, AllChecks);
+        const StringRef Closest = closest(Item.Text, AllChecks);
         if (!Closest.empty())
           Output << "; did you mean '" << Closest << '\'';
         Output << VerifyConfigWarningEnd;
@@ -572,7 +572,7 @@ static bool verifyOptions(const llvm::StringSet<> &ValidOptions,
     AnyInvalid = true;
     auto &Output = llvm::WithColor::warning(llvm::errs(), Source)
                    << "unknown check option '" << Key << '\'';
-    const llvm::StringRef Closest = closest(Key, ValidOptions);
+    const StringRef Closest = closest(Key, ValidOptions);
     if (!Closest.empty())
       Output << "; did you mean '" << Closest << '\'';
     Output << VerifyConfigWarningEnd;
@@ -580,7 +580,7 @@ static bool verifyOptions(const llvm::StringSet<> &ValidOptions,
   return AnyInvalid;
 }
 
-static SmallString<256> makeAbsolute(llvm::StringRef Input) {
+static SmallString<256> makeAbsolute(StringRef Input) {
   if (Input.empty())
     return {};
   SmallString<256> AbsolutePath(Input);
@@ -661,8 +661,8 @@ int clangTidyMain(int argc, const char **argv) {
 
   if (ExplainConfig) {
     // FIXME: Show other ClangTidyOptions' fields, like ExtraArg.
-    std::vector<clang::tidy::ClangTidyOptionsProvider::OptionsSource>
-        RawOptions = OptionsProvider->getRawOptions(FilePath);
+    std::vector<ClangTidyOptionsProvider::OptionsSource> RawOptions =
+        OptionsProvider->getRawOptions(FilePath);
     for (const std::string &Check : EnabledChecks) {
       for (const auto &[Opts, Source] : llvm::reverse(RawOptions)) {
         if (Opts.Checks && GlobList(*Opts.Checks).contains(Check)) {
diff --git a/clang-tools-extra/clang-tidy/utils/ASTUtils.cpp b/clang-tools-extra/clang-tidy/utils/ASTUtils.cpp
index c8d59a9c63c14..4baef7539008a 100644
--- a/clang-tools-extra/clang-tidy/utils/ASTUtils.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ASTUtils.cpp
@@ -100,8 +100,8 @@ bool areStatementsIdentical(const Stmt *FirstStmt, const Stmt *SecondStmt,
   if (isa<Expr>(FirstStmt) && isa<Expr>(SecondStmt)) {
     // If we have errors in expressions, we will be unable
     // to accurately profile and compute hashes for each statements.
-    if (llvm::cast<Expr>(FirstStmt)->containsErrors() ||
-        llvm::cast<Expr>(SecondStmt)->containsErrors())
+    if (cast<Expr>(FirstStmt)->containsErrors() ||
+        cast<Expr>(SecondStmt)->containsErrors())
       return false;
   }
 
diff --git a/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp b/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
index 3510b3546bbba..fbcdd1004cec0 100644
--- a/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
+++ b/clang-tools-extra/clang-tidy/utils/DeclRefExprUtils.cpp
@@ -181,7 +181,7 @@ AST_MATCHER_P(DeclRefExpr, doesNotMutateObject, int, Indirections) {
     int Indirections;
   };
 
-  llvm::SmallVector<StackEntry, 4> Stack;
+  SmallVector<StackEntry, 4> Stack;
   Stack.emplace_back(&Node, Indirections);
   ASTContext &Ctx = Finder->getASTContext();
 
diff --git a/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.cpp b/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.cpp
index e22ae8a5095be..908a1b5ec4e09 100644
--- a/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.cpp
+++ b/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.cpp
@@ -20,7 +20,7 @@
 namespace clang::tidy::utils {
 
 /// Returns true if Name is reserved, like _Foo or __Vector_base.
-static inline bool isReservedName(llvm::StringRef Name) {
+static inline bool isReservedName(StringRef Name) {
   // This doesn't catch all cases, but the most common.
   return Name.size() >= 2 && Name[0] == '_' &&
          (isUppercase(Name[1]) || Name[1] == '_');
@@ -47,7 +47,7 @@ class AggregateDesignatorNames {
         Valid = true;
         FieldsIt = RD->field_begin();
         FieldsEnd = RD->field_end();
-        if (const auto *CRD = llvm::dyn_cast<CXXRecordDecl>(RD)) {
+        if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) {
           BasesIt = CRD->bases_begin();
           BasesEnd = CRD->bases_end();
           Valid = CRD->isAggregate();
@@ -80,7 +80,7 @@ class AggregateDesignatorNames {
     if (BasesIt != BasesEnd)
       return false; // Bases can't be designated. Should we make one up?
     if (FieldsIt != FieldsEnd) {
-      llvm::StringRef FieldName;
+      StringRef FieldName;
       if (const IdentifierInfo *II = FieldsIt->getIdentifier())
         FieldName = II->getName();
 
@@ -148,10 +148,10 @@ static void collectDesignators(
     });
     // Skip for a broken initializer or if it is a "hole" in a subobject that
     // was not explicitly initialized.
-    if (!Init || llvm::isa<ImplicitValueInitExpr>(Init))
+    if (!Init || isa<ImplicitValueInitExpr>(Init))
       continue;
 
-    const auto *BraceElidedSubobject = llvm::dyn_cast<InitListExpr>(Init);
+    const auto *BraceElidedSubobject = dyn_cast<InitListExpr>(Init);
     if (BraceElidedSubobject &&
         NestedBraces.contains(BraceElidedSubobject->getLBraceLoc()))
       BraceElidedSubobject = nullptr; // there were braces!
@@ -180,7 +180,7 @@ getUnwrittenDesignators(const InitListExpr *Syn) {
   // Instead, record where braces of sub-init-lists occur in the syntactic form.
   llvm::DenseSet<SourceLocation> NestedBraces;
   for (const Expr *Init : Syn->inits())
-    if (auto *Nested = llvm::dyn_cast<InitListExpr>(Init))
+    if (auto *Nested = dyn_cast<InitListExpr>(Init))
       NestedBraces.insert(Nested->getLBraceLoc());
 
   // Traverse the semantic form to find the designators.
diff --git a/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.h b/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.h
index 1960eabf074c5..e1dca2bdf65df 100644
--- a/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.h
+++ b/clang-tools-extra/clang-tidy/utils/DesignatedInitializers.h
@@ -39,8 +39,8 @@ namespace clang::tidy::utils {
 /// It also considers structs with fields of record types like
 /// `struct T { S s; };`. In this case, there would be designators of the
 /// form `.s.i` and `.s.j` in the returned map.
-llvm::DenseMap<clang::SourceLocation, std::string>
-getUnwrittenDesignators(const clang::InitListExpr *Syn);
+llvm::DenseMap<SourceLocation, std::string>
+getUnwrittenDesignators(const InitListExpr *Syn);
 
 } // namespace clang::tidy::utils
 
diff --git a/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp b/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
index 60dade82e6155..2a54de88dc4d6 100644
--- a/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
@@ -357,7 +357,7 @@ static bool canThrow(const FunctionDecl *Func) {
 ExceptionAnalyzer::ExceptionInfo::Throwables
 ExceptionAnalyzer::ExceptionInfo::filterByCatch(const Type *HandlerTy,
                                                 const ASTContext &Context) {
-  llvm::SmallVector<const Type *, 8> TypesToDelete;
+  SmallVector<const Type *, 8> TypesToDelete;
   for (const auto &ThrownException : ThrownExceptions) {
     const Type *ExceptionTy = ThrownException.getFirst();
     const CanQualType ExceptionCanTy =
@@ -427,7 +427,7 @@ ExceptionAnalyzer::ExceptionInfo::filterByCatch(const Type *HandlerTy,
 ExceptionAnalyzer::ExceptionInfo &
 ExceptionAnalyzer::ExceptionInfo::filterIgnoredExceptions(
     const llvm::StringSet<> &IgnoredTypes, bool IgnoreBadAlloc) {
-  llvm::SmallVector<const Type *, 8> TypesToDelete;
+  SmallVector<const Type *, 8> TypesToDelete;
   // Note: Using a 'SmallSet' with 'llvm::remove_if()' is not possible.
   // Therefore this slightly hacky implementation is required.
   for (const auto &ThrownException : ThrownExceptions) {
diff --git a/clang-tools-extra/clang-tidy/utils/ExprSequence.cpp b/clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
index 699b6b7d083f2..e75782ed6795a 100644
--- a/clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
@@ -67,9 +67,9 @@ static bool isDescendantOfArgs(const Stmt *Descendant, const CallExpr *Call,
                       });
 }
 
-static llvm::SmallVector<const InitListExpr *>
+static SmallVector<const InitListExpr *>
 getAllInitListForms(const InitListExpr *InitList) {
-  llvm::SmallVector<const InitListExpr *> Result = {InitList};
+  SmallVector<const InitListExpr *> Result = {InitList};
   if (const InitListExpr *AltForm = InitList->getSyntacticForm())
     Result.push_back(AltForm);
   if (const InitListExpr *AltForm = InitList->getSemanticForm())
diff --git a/clang-tools-extra/clang-tidy/utils/FixItHintUtils.cpp b/clang-tools-extra/clang-tidy/utils/FixItHintUtils.cpp
index 9eca12fe19bf1..9624148411eac 100644
--- a/clang-tools-extra/clang-tidy/utils/FixItHintUtils.cpp
+++ b/clang-tools-extra/clang-tidy/utils/FixItHintUtils.cpp
@@ -235,11 +235,10 @@ bool areParensNeededForStatement(const Stmt &Node) {
   if (isa<ParenExpr>(&Node))
     return false;
 
-  if (isa<clang::BinaryOperator>(&Node) || isa<UnaryOperator>(&Node))
+  if (isa<BinaryOperator, UnaryOperator>(&Node))
     return true;
 
-  if (isa<clang::ConditionalOperator>(&Node) ||
-      isa<BinaryConditionalOperator>(&Node))
+  if (isa<ConditionalOperator, BinaryConditionalOperator>(&Node))
     return true;
 
   if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(&Node))
@@ -268,10 +267,8 @@ bool areParensNeededForStatement(const Stmt &Node) {
 // prefix unary operator, e.g. when it is a binary or ternary operator
 // syntactically.
 static bool needParensAfterUnaryOperator(const Expr &ExprNode) {
-  if (isa<clang::BinaryOperator>(&ExprNode) ||
-      isa<clang::ConditionalOperator>(&ExprNode)) {
+  if (isa<BinaryOperator, ConditionalOperator>(&ExprNode))
     return true;
-  }
   if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(&ExprNode)) {
     return Op->getNumArgs() == 2 && Op->getOperator() != OO_PlusPlus &&
            Op->getOperator() != OO_MinusMinus && Op->getOperator() != OO_Call &&
@@ -283,7 +280,7 @@ static bool needParensAfterUnaryOperator(const Expr &ExprNode) {
 // Format a pointer to an expression: prefix with '*' but simplify
 // when it already begins with '&'.  Return empty string on failure.
 std::string formatDereference(const Expr &ExprNode, const ASTContext &Context) {
-  if (const auto *Op = dyn_cast<clang::UnaryOperator>(&ExprNode)) {
+  if (const auto *Op = dyn_cast<UnaryOperator>(&ExprNode)) {
     if (Op->getOpcode() == UO_AddrOf) {
       // Strip leading '&'.
       return std::string(
diff --git a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
index 1f6614141196a..070a286fdebc4 100644
--- a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
+++ b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
@@ -32,10 +32,10 @@ using clang::analyze_format_string::ConversionSpecifier;
 
 /// Is the passed type the actual "char" type, whether that be signed or
 /// unsigned, rather than explicit signed char or unsigned char types.
-static bool isRealCharType(const clang::QualType &Ty) {
+static bool isRealCharType(const QualType &Ty) {
   using namespace clang;
   const Type *DesugaredType = Ty->getUnqualifiedDesugaredType();
-  if (const auto *BT = llvm::dyn_cast<BuiltinType>(DesugaredType))
+  if (const auto *BT = dyn_cast<BuiltinType>(DesugaredType))
     return (BT->getKind() == BuiltinType::Char_U ||
             BT->getKind() == BuiltinType::Char_S);
   return false;
@@ -45,10 +45,10 @@ static bool isRealCharType(const clang::QualType &Ty) {
 /// passed integer type. If the passed type is already signed then its name is
 /// just returned. Only supports BuiltinTypes.
 static std::optional<std::string>
-getCorrespondingSignedTypeName(const clang::QualType &QT) {
+getCorrespondingSignedTypeName(const QualType &QT) {
   using namespace clang;
   const auto UQT = QT.getUnqualifiedType();
-  if (const auto *BT = llvm::dyn_cast<BuiltinType>(UQT)) {
+  if (const auto *BT = dyn_cast<BuiltinType>(UQT)) {
     switch (BT->getKind()) {
     case BuiltinType::UChar:
     case BuiltinType::Char_U:
@@ -97,10 +97,10 @@ getCorrespondingSignedTypeName(const clang::QualType &QT) {
 /// the passed integer type. If the passed type is already unsigned then its
 /// name is just returned. Only supports BuiltinTypes.
 static std::optional<std::string>
-getCorrespondingUnsignedTypeName(const clang::QualType &QT) {
+getCorrespondingUnsignedTypeName(const QualType &QT) {
   using namespace clang;
   const auto UQT = QT.getUnqualifiedType();
-  if (const auto *BT = llvm::dyn_cast<BuiltinType>(UQT)) {
+  if (const auto *BT = dyn_cast<BuiltinType>(UQT)) {
     switch (BT->getKind()) {
     case BuiltinType::SChar:
     case BuiltinType::Char_S:
@@ -148,16 +148,15 @@ getCorrespondingUnsignedTypeName(const clang::QualType &QT) {
 }
 
 static std::optional<std::string>
-castTypeForArgument(ConversionSpecifier::Kind ArgKind,
-                    const clang::QualType &QT) {
+castTypeForArgument(ConversionSpecifier::Kind ArgKind, const QualType &QT) {
   if (ArgKind == ConversionSpecifier::Kind::uArg)
     return getCorrespondingUnsignedTypeName(QT);
   return getCorrespondingSignedTypeName(QT);
 }
 
 static bool isMatchingSignedness(ConversionSpecifier::Kind ArgKind,
-                                 const clang::QualType &ArgType) {
-  if (const auto *BT = llvm::dyn_cast<BuiltinType>(ArgType)) {
+                                 const QualType &ArgType) {
+  if (const auto *BT = dyn_cast<BuiltinType>(ArgType)) {
     // Unadorned char never matches any expected signedness since it
     // could be signed or unsigned.
     const auto ArgTypeKind = BT->getKind();
@@ -172,9 +171,7 @@ static bool isMatchingSignedness(ConversionSpecifier::Kind ArgKind,
 }
 
 namespace {
-AST_MATCHER(clang::QualType, isRealChar) {
-  return clang::tidy::utils::isRealCharType(Node);
-}
+AST_MATCHER(QualType, isRealChar) { return utils::isRealCharType(Node); }
 } // namespace
 
 static bool castMismatchedIntegerTypes(const CallExpr *Call, bool StrictMode) {
@@ -207,7 +204,7 @@ FormatStringConverter::FormatStringConverter(
       Args(Call->getArgs()), NumArgs(Call->getNumArgs()),
       ArgsOffset(FormatArgOffset + 1), LangOpts(LO) {
   assert(ArgsOffset <= NumArgs);
-  FormatExpr = llvm::dyn_cast<StringLiteral>(
+  FormatExpr = dyn_cast<StringLiteral>(
       Args[FormatArgOffset]->IgnoreUnlessSpelledInSource());
 
   assert(FormatExpr && FormatExpr->isOrdinary());
@@ -450,7 +447,7 @@ void FormatStringConverter::emitStringArgument(unsigned ArgIndex,
 bool FormatStringConverter::emitIntegerArgument(
     ConversionSpecifier::Kind ArgKind, const Expr *Arg, unsigned ArgIndex,
     std::string &FormatSpec) {
-  const clang::QualType &ArgType = Arg->getType();
+  const QualType &ArgType = Arg->getType();
   if (ArgType->isBooleanType()) {
     // std::format will print bool as either "true" or "false" by default,
     // but printf prints them as "0" or "1". Be compatible with printf by
@@ -521,7 +518,7 @@ bool FormatStringConverter::emitType(const PrintfSpecifier &FS, const Expr *Arg,
       return false;
     break;
   case ConversionSpecifier::Kind::pArg: {
-    const clang::QualType &ArgType = Arg->getType();
+    const QualType &ArgType = Arg->getType();
     // std::format knows how to format void pointers and nullptrs
     if (!ArgType->isNullPtrType() && !ArgType->isVoidPointerType())
       ArgFixes.emplace_back(FS.getArgIndex() + ArgsOffset,
diff --git a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.h b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.h
index 209741fac276c..e413b9f4c79f0 100644
--- a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.h
+++ b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.h
@@ -65,8 +65,7 @@ class FormatStringConverter
   StringRef PrintfFormatString;
 
   /// Lazily-created c_str() call matcher
-  std::optional<clang::ast_matchers::StatementMatcher>
-      StringCStrCallExprMatcher;
+  std::optional<ast_matchers::StatementMatcher> StringCStrCallExprMatcher;
 
   const StringLiteral *FormatExpr;
   std::string StandardFormatString;
@@ -82,7 +81,7 @@ class FormatStringConverter
   };
 
   std::vector<ArgumentFix> ArgFixes;
-  std::vector<clang::ast_matchers::BoundNodes> ArgCStrRemovals;
+  std::vector<ast_matchers::BoundNodes> ArgCStrRemovals;
 
   // Argument rotations to cope with the fact that std::print puts the value to
   // be formatted first and the width and precision afterwards whereas printf
diff --git a/clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp b/clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp
index 81bb8dec57a74..1ba5d96d06e4b 100644
--- a/clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp
+++ b/clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp
@@ -68,7 +68,7 @@ IncludeSorter &IncludeInserter::getOrCreate(FileID FileID) {
 }
 
 std::optional<FixItHint>
-IncludeInserter::createIncludeInsertion(FileID FileID, llvm::StringRef Header) {
+IncludeInserter::createIncludeInsertion(FileID FileID, StringRef Header) {
   const bool IsAngled = Header.consume_front("<");
   if (IsAngled != Header.consume_back(">"))
     return std::nullopt;
diff --git a/clang-tools-extra/clang-tidy/utils/IncludeInserter.h b/clang-tools-extra/clang-tidy/utils/IncludeInserter.h
index 9dbf2a76369cd..95e497aed0e1e 100644
--- a/clang-tools-extra/clang-tidy/utils/IncludeInserter.h
+++ b/clang-tools-extra/clang-tidy/utils/IncludeInserter.h
@@ -72,15 +72,14 @@ class IncludeInserter {
   /// Returns ``std::nullopt`` on error or if the inclusion directive already
   /// exists.
   std::optional<FixItHint> createIncludeInsertion(FileID FileID,
-                                                  llvm::StringRef Header);
+                                                  StringRef Header);
 
   /// Creates a \p Header inclusion directive fixit in the main file.
   /// When \p Header is enclosed in angle brackets, uses angle brackets in the
   /// inclusion directive, otherwise uses quotes.
   /// Returns ``std::nullopt`` on error or if the inclusion directive already
   /// exists.
-  std::optional<FixItHint>
-  createMainFileIncludeInsertion(llvm::StringRef Header);
+  std::optional<FixItHint> createMainFileIncludeInsertion(StringRef Header);
 
   IncludeSorter::IncludeStyle getStyle() const { return Style; }
 
diff --git a/clang-tools-extra/clang-tidy/utils/Matchers.cpp b/clang-tools-extra/clang-tidy/utils/Matchers.cpp
index b1591fb8e3619..89cf09a28a1b6 100644
--- a/clang-tools-extra/clang-tidy/utils/Matchers.cpp
+++ b/clang-tools-extra/clang-tidy/utils/Matchers.cpp
@@ -12,7 +12,7 @@
 namespace clang::tidy::matchers {
 
 bool NotIdenticalStatementsPredicate::operator()(
-    const clang::ast_matchers::internal::BoundNodesMap &Nodes) const {
+    const ast_matchers::internal::BoundNodesMap &Nodes) const {
   return !utils::areStatementsIdentical(Node.get<Stmt>(),
                                         Nodes.getNodeAs<Stmt>(ID), *Context);
 }
diff --git a/clang-tools-extra/clang-tidy/utils/Matchers.h b/clang-tools-extra/clang-tidy/utils/Matchers.h
index 4637809c17c81..674f871493dfd 100644
--- a/clang-tools-extra/clang-tidy/utils/Matchers.h
+++ b/clang-tools-extra/clang-tidy/utils/Matchers.h
@@ -82,9 +82,8 @@ class MatchesAnyListedRegexNameMatcher
 public:
   explicit MatchesAnyListedRegexNameMatcher(
       llvm::ArrayRef<StringRef> NameList) {
-    llvm::transform(
-        NameList, std::back_inserter(NameMatchers),
-        [](const llvm::StringRef Name) { return NameMatcher(Name); });
+    llvm::transform(NameList, std::back_inserter(NameMatchers),
+                    [](const StringRef Name) { return NameMatcher(Name); });
   }
 
   class NameMatcher {
@@ -103,7 +102,7 @@ class MatchesAnyListedRegexNameMatcher
     MatchMode Mode;
 
   public:
-    NameMatcher(const llvm::StringRef Regex)
+    NameMatcher(const StringRef Regex)
         : Regex(Regex), Mode(determineMatchMode(Regex)) {}
 
     bool match(const NamedDecl &ND) const {
@@ -120,7 +119,7 @@ class MatchesAnyListedRegexNameMatcher
     }
 
   private:
-    MatchMode determineMatchMode(llvm::StringRef Regex) {
+    MatchMode determineMatchMode(StringRef Regex) {
       if (Regex.starts_with(":") || Regex.starts_with("^:"))
         return MatchMode::MatchFullyQualified;
       return Regex.contains(":") ? MatchMode::MatchQualified
diff --git a/clang-tools-extra/clang-tidy/utils/NamespaceAliaser.h b/clang-tools-extra/clang-tidy/utils/NamespaceAliaser.h
index fbf0ade3b0cc7..6a8eab4bbd132 100644
--- a/clang-tools-extra/clang-tidy/utils/NamespaceAliaser.h
+++ b/clang-tools-extra/clang-tidy/utils/NamespaceAliaser.h
@@ -28,14 +28,13 @@ class NamespaceAliaser {
   // Statement. Picks the first available name from \p Abbreviations.
   // Returns ``std::nullopt`` if an alias already exists or there is an error.
   std::optional<FixItHint>
-  createAlias(ASTContext &Context, const Stmt &Statement,
-              llvm::StringRef Namespace,
+  createAlias(ASTContext &Context, const Stmt &Statement, StringRef Namespace,
               const std::vector<std::string> &Abbreviations);
 
   // Get an alias name for \p Namespace valid at \p Statement. Returns \p
   // Namespace if there is no alias.
   std::string getNamespaceName(ASTContext &Context, const Stmt &Statement,
-                               llvm::StringRef Namespace) const;
+                               StringRef Namespace) const;
 
 private:
   const SourceManager &SourceMgr;
diff --git a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
index 5ad96a5e4c0f2..0e4a6f49116da 100644
--- a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
@@ -153,7 +153,7 @@ static NameLookup findDeclInBases(const CXXRecordDecl &Parent,
     if (!Record && AggressiveTemplateLookup) {
       if (const auto *TST =
               Base.getType()->getAs<TemplateSpecializationType>()) {
-        if (const auto *TD = llvm::dyn_cast_or_null<ClassTemplateDecl>(
+        if (const auto *TD = dyn_cast_or_null<ClassTemplateDecl>(
                 TST->getTemplateName().getAsTemplateDecl()))
           Record = TD->getTemplatedDecl();
       }
diff --git a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
index 004e61526b778..fcc85b4db32f9 100644
--- a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
@@ -110,9 +110,9 @@ void UseRangesCheck::registerMatchers(MatchFinder *Finder) {
   auto Replaces = getReplacerMap();
   ReverseDescriptor = getReverseDescriptor();
   auto BeginEndNames = getFreeBeginEndMethods();
-  const llvm::SmallVector<StringRef, 4> BeginNames{
+  const SmallVector<StringRef, 4> BeginNames{
       llvm::make_first_range(BeginEndNames)};
-  const llvm::SmallVector<StringRef, 4> EndNames{
+  const SmallVector<StringRef, 4> EndNames{
       llvm::make_second_range(BeginEndNames)};
   Replacers.clear();
   llvm::DenseSet<Replacer *> SeenRepl;
@@ -163,7 +163,7 @@ void UseRangesCheck::registerMatchers(MatchFinder *Finder) {
 static void removeFunctionArgs(DiagnosticBuilder &Diag, const CallExpr &Call,
                                ArrayRef<unsigned> Indexes,
                                const ASTContext &Ctx) {
-  llvm::SmallVector<unsigned> Sorted(Indexes);
+  SmallVector<unsigned> Sorted(Indexes);
   llvm::sort(Sorted);
   // Keep track of commas removed
   llvm::SmallBitVector Commas(Call.getNumArgs());
@@ -233,7 +233,7 @@ void UseRangesCheck::check(const MatchFinder::MatchResult &Result) {
     if (auto Include = Replacer->getHeaderInclusion(*Function))
       Diag << Inserter.createIncludeInsertion(
           Result.SourceManager->getFileID(Call->getBeginLoc()), *Include);
-    llvm::SmallVector<unsigned, 3> ToRemove;
+    SmallVector<unsigned, 3> ToRemove;
     for (const auto &[First, Second, Replace] : Sig) {
       auto ArgNode = ArgName + std::to_string(First);
       if (const auto *ArgExpr = Result.Nodes.getNodeAs<Expr>(ArgNode)) {
diff --git a/clang-tools-extra/clang-tidy/utils/UsingInserter.h b/clang-tools-extra/clang-tidy/utils/UsingInserter.h
index 3e943569047ae..f39009a7db6e4 100644
--- a/clang-tools-extra/clang-tidy/utils/UsingInserter.h
+++ b/clang-tools-extra/clang-tidy/utils/UsingInserter.h
@@ -27,14 +27,14 @@ class UsingInserter {
 
   // Creates a \p using declaration fixit. Returns ``std::nullopt`` on error
   // or if the using declaration already exists.
-  std::optional<FixItHint>
-  createUsingDeclaration(ASTContext &Context, const Stmt &Statement,
-                         llvm::StringRef QualifiedName);
+  std::optional<FixItHint> createUsingDeclaration(ASTContext &Context,
+                                                  const Stmt &Statement,
+                                                  StringRef QualifiedName);
 
   // Returns the unqualified version of the name if there is an
   // appropriate using declaration and the qualified name otherwise.
-  llvm::StringRef getShortName(ASTContext &Context, const Stmt &Statement,
-                               llvm::StringRef QualifiedName);
+  StringRef getShortName(ASTContext &Context, const Stmt &Statement,
+                         StringRef QualifiedName);
 
 private:
   using NameInFunction = std::pair<const FunctionDecl *, std::string>;



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