[clang] [Clang][C++26] Implement Pack Indexing (P2662R3). (PR #72644)

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git-clang-format --diff ec42d547eba5c0ad0bddbecc8902d35383968e78 ac0f8313637763fe0ffcaf7f45cf803babe1b65b -- clang/test/PCH/pack_indexing.cpp clang/test/Parser/cxx2b-pack-indexing.cpp clang/test/SemaCXX/cxx2b-pack-indexing.cpp clang/include/clang-c/Index.h clang/include/clang/AST/ASTContext.h clang/include/clang/AST/ASTNodeTraverser.h clang/include/clang/AST/ExprCXX.h clang/include/clang/AST/RecursiveASTVisitor.h clang/include/clang/AST/Type.h clang/include/clang/AST/TypeLoc.h clang/include/clang/Basic/Specifiers.h clang/include/clang/Parse/Parser.h clang/include/clang/Sema/DeclSpec.h clang/include/clang/Sema/Sema.h clang/include/clang/Serialization/ASTBitCodes.h clang/lib/AST/ASTContext.cpp clang/lib/AST/ASTImporter.cpp clang/lib/AST/ASTStructuralEquivalence.cpp clang/lib/AST/Expr.cpp clang/lib/AST/ExprCXX.cpp clang/lib/AST/ExprClassification.cpp clang/lib/AST/ExprConstant.cpp clang/lib/AST/ItaniumMangle.cpp clang/lib/AST/MicrosoftMangle.cpp clang/lib/AST/StmtPrinter.cpp clang/lib/AST/StmtProfile.cpp clang/lib/AST/Type.cpp clang/lib/AST/TypePrinter.cpp clang/lib/CodeGen/CGDebugInfo.cpp clang/lib/CodeGen/CGExpr.cpp clang/lib/CodeGen/CGExprAgg.cpp clang/lib/CodeGen/CGExprComplex.cpp clang/lib/CodeGen/CGExprConstant.cpp clang/lib/CodeGen/CGExprScalar.cpp clang/lib/CodeGen/CodeGenFunction.cpp clang/lib/Parse/ParseCXXInlineMethods.cpp clang/lib/Parse/ParseDecl.cpp clang/lib/Parse/ParseDeclCXX.cpp clang/lib/Parse/ParseExpr.cpp clang/lib/Parse/ParseExprCXX.cpp clang/lib/Parse/ParseTentative.cpp clang/lib/Parse/Parser.cpp clang/lib/Sema/DeclSpec.cpp clang/lib/Sema/SemaCXXScopeSpec.cpp clang/lib/Sema/SemaDecl.cpp clang/lib/Sema/SemaDeclCXX.cpp clang/lib/Sema/SemaExceptionSpec.cpp clang/lib/Sema/SemaExpr.cpp clang/lib/Sema/SemaExprCXX.cpp clang/lib/Sema/SemaTemplate.cpp clang/lib/Sema/SemaTemplateDeduction.cpp clang/lib/Sema/SemaTemplateVariadic.cpp clang/lib/Sema/SemaType.cpp clang/lib/Sema/TreeTransform.h clang/lib/Serialization/ASTReader.cpp clang/lib/Serialization/ASTReaderStmt.cpp clang/lib/Serialization/ASTWriter.cpp clang/lib/Serialization/ASTWriterStmt.cpp clang/lib/StaticAnalyzer/Core/ExprEngine.cpp clang/tools/libclang/CIndex.cpp clang/tools/libclang/CXCursor.cpp
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View the diff from clang-format here.
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diff --git a/clang/include/clang/Basic/Specifiers.h b/clang/include/clang/Basic/Specifiers.h
index bff4c1616c..54ef5dd634 100644
--- a/clang/include/clang/Basic/Specifiers.h
+++ b/clang/include/clang/Basic/Specifiers.h
@@ -79,14 +79,14 @@ namespace clang {
     TST_enum,
     TST_union,
     TST_struct,
-    TST_class,     // C++ class type
-    TST_interface, // C++ (Microsoft-specific) __interface type
-    TST_typename,  // Typedef, C++ class-name or enum name, etc.
+    TST_class,             // C++ class type
+    TST_interface,         // C++ (Microsoft-specific) __interface type
+    TST_typename,          // Typedef, C++ class-name or enum name, etc.
     TST_typeofType,        // C23 (and GNU extension) typeof(type-name)
     TST_typeofExpr,        // C23 (and GNU extension) typeof(expression)
     TST_typeof_unqualType, // C23 typeof_unqual(type-name)
     TST_typeof_unqualExpr, // C23 typeof_unqual(expression)
-    TST_decltype, // C++11 decltype
+    TST_decltype,          // C++11 decltype
 #define TRANSFORM_TYPE_TRAIT_DEF(_, Trait) TST_##Trait,
 #include "clang/Basic/TransformTypeTraits.def"
     TST_auto,            // C++11 auto
@@ -95,7 +95,8 @@ namespace clang {
     TST_unknown_anytype, // __unknown_anytype extension
     TST_atomic,          // C11 _Atomic
     TST_indexed_typename_pack,
-#define GENERIC_IMAGE_TYPE(ImgType, Id) TST_##ImgType##_t, // OpenCL image types
+#define GENERIC_IMAGE_TYPE(ImgType, Id)                                      \
+    TST_##ImgType##_t, // OpenCL image types
 #include "clang/Basic/OpenCLImageTypes.def"
     TST_error // erroneous type
   };

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https://github.com/llvm/llvm-project/pull/72644