[clang-tools-extra] Enforce SL.con.3: Add check to replace operator[] with at() [Cont.] (PR #95220)

[Paul Heidekrüger via cfe-commits]

https://github.com/PBHDK updated https://github.com/llvm/llvm-project/pull/95220

>From 37292995de0c5aa87408586749795a97468d4725 Mon Sep 17 00:00:00 2001
From: Sebastian Wolf <wolf.sebastian at in.tum.de>
Date: Wed, 17 Apr 2024 16:16:35 +0200
Subject: [PATCH 01/28] Enforce SL.con.3: Add check to replace operator[] with
 at() on std containers

---
 .../AvoidBoundsErrorsCheck.cpp                | 81 +++++++++++++++++++
 .../AvoidBoundsErrorsCheck.h                  | 32 ++++++++
 .../cppcoreguidelines/CMakeLists.txt          |  1 +
 .../CppCoreGuidelinesTidyModule.cpp           |  3 +
 clang-tools-extra/docs/ReleaseNotes.rst       |  5 ++
 .../cppcoreguidelines/avoid-bounds-errors.rst | 20 +++++
 .../docs/clang-tidy/checks/list.rst           |  1 +
 .../cppcoreguidelines/avoid-bounds-errors.cpp | 66 +++++++++++++++
 8 files changed, 209 insertions(+)
 create mode 100644 clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
 create mode 100644 clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
 create mode 100644 clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
 create mode 100644 clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
new file mode 100644
index 0000000000000..524c21b5bdb81
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
@@ -0,0 +1,81 @@
+//===--- AvoidBoundsErrorsCheck.cpp - clang-tidy --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AvoidBoundsErrorsCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+#include <iostream>
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::cppcoreguidelines {
+
+bool isApplicable(const QualType &Type) {
+  const auto TypeStr = Type.getAsString();
+  bool Result = false;
+  // Only check for containers in the std namespace
+  if (TypeStr.find("std::vector") != std::string::npos) {
+    Result = true;
+  }
+  if (TypeStr.find("std::array") != std::string::npos) {
+    Result = true;
+  }
+  if (TypeStr.find("std::deque") != std::string::npos) {
+    Result = true;
+  }
+  if (TypeStr.find("std::map") != std::string::npos) {
+    Result = true;
+  }
+  if (TypeStr.find("std::unordered_map") != std::string::npos) {
+    Result = true;
+  }
+  if (TypeStr.find("std::flat_map") != std::string::npos) {
+    Result = true;
+  }
+  // TODO Add std::span with C++26
+  return Result;
+}
+
+void AvoidBoundsErrorsCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      callExpr(callee(cxxMethodDecl(hasName("operator[]")).bind("f")))
+          .bind("x"),
+      this);
+}
+
+void AvoidBoundsErrorsCheck::check(const MatchFinder::MatchResult &Result) {
+  const ASTContext &Context = *Result.Context;
+  const SourceManager &Source = Context.getSourceManager();
+  const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("x");
+  const auto *MatchedFunction = Result.Nodes.getNodeAs<CXXMethodDecl>("f");
+  const auto Type = MatchedFunction->getThisType();
+  if (!isApplicable(Type)) {
+    return;
+  }
+
+  // Get original code.
+  const SourceLocation b(MatchedExpr->getBeginLoc());
+  const SourceLocation e(MatchedExpr->getEndLoc());
+  const std::string OriginalCode =
+      Lexer::getSourceText(CharSourceRange::getTokenRange(b, e), Source,
+                           getLangOpts())
+          .str();
+  const auto Range = SourceRange(b, e);
+
+  // Build replacement.
+  std::string NewCode = OriginalCode;
+  const auto BeginOpen = NewCode.find("[");
+  NewCode.replace(BeginOpen, 1, ".at(");
+  const auto BeginClose = NewCode.find("]");
+  NewCode.replace(BeginClose, 1, ")");
+
+  diag(MatchedExpr->getBeginLoc(), "Do not use operator[], use at() instead.")
+      << FixItHint::CreateReplacement(Range, NewCode);
+}
+
+} // namespace clang::tidy::cppcoreguidelines
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
new file mode 100644
index 0000000000000..f915729cd7bbe
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
@@ -0,0 +1,32 @@
+//===--- AvoidBoundsErrorsCheck.h - clang-tidy ------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::cppcoreguidelines {
+
+/// Enforce CPP core guidelines SL.con.3
+///
+/// See
+/// https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.html
+class AvoidBoundsErrorsCheck : public ClangTidyCheck {
+public:
+  AvoidBoundsErrorsCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace clang::tidy::cppcoreguidelines
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
index eb35bbc6a538f..4972d20417928 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -4,6 +4,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 add_clang_library(clangTidyCppCoreGuidelinesModule
+  AvoidBoundsErrorsCheck.cpp
   AvoidCapturingLambdaCoroutinesCheck.cpp
   AvoidConstOrRefDataMembersCheck.cpp
   AvoidDoWhileCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index e9f0201615616..525bbc7a42ada 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -19,6 +19,7 @@
 #include "../performance/NoexceptMoveConstructorCheck.h"
 #include "../performance/NoexceptSwapCheck.h"
 #include "../readability/MagicNumbersCheck.h"
+#include "AvoidBoundsErrorsCheck.h"
 #include "AvoidCapturingLambdaCoroutinesCheck.h"
 #include "AvoidConstOrRefDataMembersCheck.h"
 #include "AvoidDoWhileCheck.h"
@@ -57,6 +58,8 @@ namespace cppcoreguidelines {
 class CppCoreGuidelinesModule : public ClangTidyModule {
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+    CheckFactories.registerCheck<AvoidBoundsErrorsCheck>(
+        "cppcoreguidelines-avoid-bounds-errors");
     CheckFactories.registerCheck<AvoidCapturingLambdaCoroutinesCheck>(
         "cppcoreguidelines-avoid-capturing-lambda-coroutines");
     CheckFactories.registerCheck<modernize::AvoidCArraysCheck>(
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6bf70c5cf4f8a..a0cd0189fbb1c 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -160,6 +160,11 @@ New checks
   Replaces nested ``std::min`` and ``std::max`` calls with an initializer list
   where applicable.
 
+- New :doc:`cppcoreguidelines-avoid-bounds-errors
+  <clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors>` check.
+
+  Flags the unsafe `operator[]` and replaces it with `at()`.
+
 - New :doc:`modernize-use-designated-initializers
   <clang-tidy/checks/modernize/use-designated-initializers>` check.
 
diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
new file mode 100644
index 0000000000000..8fb2e3bfde098
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
@@ -0,0 +1,20 @@
+.. title:: clang-tidy - cppcoreguidelines-avoid-bounds-errors
+
+cppcoreguidelines-avoid-bounds-errors
+=====================================
+
+This check enforces the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.
+It flags all uses of `operator[]` on `std::vector`, `std::array`, `std::deque`, `std::map`, `std::unordered_map`, and `std::flat_map` and suggests to replace it with `at()`.
+Note that `std::span` and `std::mdspan` do not support `at()` as of C++23, so the use of `operator[]` is not flagged.
+
+For example the code
+
+.. code-block:: c++
+  std::array<int, 3> a;
+  int b = a[4];
+
+will be replaced by 
+
+.. code-block:: c++
+  std::vector<int, 3> a;
+  int b = a.at(4);
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index a698cecc0825c..d9c72bedfb95b 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -174,6 +174,7 @@ Clang-Tidy Checks
    :doc:`cert-oop58-cpp <cert/oop58-cpp>`,
    :doc:`concurrency-mt-unsafe <concurrency/mt-unsafe>`,
    :doc:`concurrency-thread-canceltype-asynchronous <concurrency/thread-canceltype-asynchronous>`,
+   :doc:`cppcoreguidelines-avoid-bounds-errors <cppcoreguidelines/avoid-bounds-errors>`, "Yes"
    :doc:`cppcoreguidelines-avoid-capturing-lambda-coroutines <cppcoreguidelines/avoid-capturing-lambda-coroutines>`,
    :doc:`cppcoreguidelines-avoid-const-or-ref-data-members <cppcoreguidelines/avoid-const-or-ref-data-members>`,
    :doc:`cppcoreguidelines-avoid-do-while <cppcoreguidelines/avoid-do-while>`,
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
new file mode 100644
index 0000000000000..23453b1f2df21
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
@@ -0,0 +1,66 @@
+namespace std {
+  template<typename T, unsigned size>
+  struct array {
+    T operator[](unsigned i) {
+      return T{1};
+    }
+    T at(unsigned i) {
+      return T{1};
+    }
+  };
+
+  template<typename T>
+  struct unique_ptr {
+    T operator[](unsigned i) {
+      return T{1};
+    }
+  };
+
+  template<typename T>
+  struct span {
+    T operator[](unsigned i) {
+      return T{1};
+    }
+  };
+} // namespace std
+
+namespace json {
+  template<typename T>
+  struct node{
+    T operator[](unsigned i) {
+      return T{1};
+    }
+  };
+} // namespace json
+
+
+// RUN: %check_clang_tidy %s cppcoreguidelines-avoid-bounds-errors %t
+std::array<int, 3> a;
+
+auto b = a[0];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-FIXES: auto b = a.at(0);
+auto c = a[1+1];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-FIXES: auto c = a.at(1+1);
+constexpr int index = 1;
+auto d = a[index];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-FIXES: auto d = a.at(index);
+
+int e(int index) {
+  return a[index];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-FIXES: return a.at(index);
+}
+
+auto f = a.at(0);
+
+std::unique_ptr<int> p;
+auto q = p[0];
+
+std::span<int> s;
+auto t = s[0];
+
+json::node<int> n;
+auto m = n[0];

>From 953e75296861e4ee359b3fc086be4ea2fcf9dd2e Mon Sep 17 00:00:00 2001
From: Sebastian Wolf <wolf.sebastian at in.tum.de>
Date: Fri, 26 Apr 2024 09:06:02 +0200
Subject: [PATCH 02/28] EugeneZelenko's comments

---
 .../cppcoreguidelines/AvoidBoundsErrorsCheck.cpp       | 10 +++++-----
 .../cppcoreguidelines/AvoidBoundsErrorsCheck.h         |  3 +++
 clang-tools-extra/docs/ReleaseNotes.rst                |  2 +-
 .../checks/cppcoreguidelines/avoid-bounds-errors.rst   |  7 ++++---
 4 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
index 524c21b5bdb81..2c0a12e21d726 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
@@ -9,13 +9,13 @@
 #include "AvoidBoundsErrorsCheck.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Lex/Lexer.h"
-
 #include <iostream>
+
 using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
-bool isApplicable(const QualType &Type) {
+static bool isApplicable(const QualType &Type) {
   const auto TypeStr = Type.getAsString();
   bool Result = false;
   // Only check for containers in the std namespace
@@ -51,9 +51,9 @@ void AvoidBoundsErrorsCheck::registerMatchers(MatchFinder *Finder) {
 void AvoidBoundsErrorsCheck::check(const MatchFinder::MatchResult &Result) {
   const ASTContext &Context = *Result.Context;
   const SourceManager &Source = Context.getSourceManager();
-  const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("x");
-  const auto *MatchedFunction = Result.Nodes.getNodeAs<CXXMethodDecl>("f");
-  const auto Type = MatchedFunction->getThisType();
+  const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("x");
+  const CXXMethodDecl *MatchedFunction = Result.Nodes.getNodeAs<CXXMethodDecl>("f");
+  const QualType Type = MatchedFunction->getThisType();
   if (!isApplicable(Type)) {
     return;
   }
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
index f915729cd7bbe..12c7852877123 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
@@ -23,6 +23,9 @@ class AvoidBoundsErrorsCheck : public ClangTidyCheck {
 public:
   AvoidBoundsErrorsCheck(StringRef Name, ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context) {}
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return LangOpts.CPlusPlus;
+  }
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 };
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index a0cd0189fbb1c..0106b6ea732db 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -163,7 +163,7 @@ New checks
 - New :doc:`cppcoreguidelines-avoid-bounds-errors
   <clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors>` check.
 
-  Flags the unsafe `operator[]` and replaces it with `at()`.
+  Flags the unsafe ``operator[]`` and replaces it with ``at()``.
 
 - New :doc:`modernize-use-designated-initializers
   <clang-tidy/checks/modernize/use-designated-initializers>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
index 8fb2e3bfde098..13683ee9b5a46 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
@@ -3,9 +3,8 @@
 cppcoreguidelines-avoid-bounds-errors
 =====================================
 
-This check enforces the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.
-It flags all uses of `operator[]` on `std::vector`, `std::array`, `std::deque`, `std::map`, `std::unordered_map`, and `std::flat_map` and suggests to replace it with `at()`.
-Note that `std::span` and `std::mdspan` do not support `at()` as of C++23, so the use of `operator[]` is not flagged.
+This check flags all uses of ``operator[]`` on ``std::vector``, ``std::array``, ``std::deque``, ``std::map``, ``std::unordered_map``, and ``std::flat_map`` and suggests to replace it with ``at()``.
+Note that ``std::span`` and ``std::mdspan`` do not support ``at()`` as of C++23, so the use of ``operator[]`` is not flagged.
 
 For example the code
 
@@ -18,3 +17,5 @@ will be replaced by
 .. code-block:: c++
   std::vector<int, 3> a;
   int b = a.at(4);
+
+This check enforces the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.

>From ae98aa1d46bb71111f35b1af4b7a01dc5cb11281 Mon Sep 17 00:00:00 2001
From: Sebastian Wolf <wolf.sebastian at in.tum.de>
Date: Fri, 24 May 2024 12:09:11 +0200
Subject: [PATCH 03/28] Refactoring, but not finished yet

---
 .../AvoidBoundsErrorsCheck.cpp                | 97 ++++++++++---------
 .../cppcoreguidelines/avoid-bounds-errors.cpp | 17 ++--
 2 files changed, 57 insertions(+), 57 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
index 2c0a12e21d726..f10b97820f4c7 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
@@ -9,73 +9,74 @@
 #include "AvoidBoundsErrorsCheck.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Lex/Lexer.h"
-#include <iostream>
 
 using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
-static bool isApplicable(const QualType &Type) {
-  const auto TypeStr = Type.getAsString();
-  bool Result = false;
-  // Only check for containers in the std namespace
-  if (TypeStr.find("std::vector") != std::string::npos) {
-    Result = true;
-  }
-  if (TypeStr.find("std::array") != std::string::npos) {
-    Result = true;
-  }
-  if (TypeStr.find("std::deque") != std::string::npos) {
-    Result = true;
-  }
-  if (TypeStr.find("std::map") != std::string::npos) {
-    Result = true;
-  }
-  if (TypeStr.find("std::unordered_map") != std::string::npos) {
-    Result = true;
-  }
-  if (TypeStr.find("std::flat_map") != std::string::npos) {
-    Result = true;
+const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
+                                     const CXXMethodDecl *MatchedOperator) {
+  for (const CXXMethodDecl *Method : MatchedParent->methods()) {
+    const bool CorrectName = Method->getNameInfo().getAsString() == "at";
+    if (!CorrectName)
+      continue;
+
+    const bool SameReturnType =
+        Method->getReturnType() == MatchedOperator->getReturnType();
+    if (!SameReturnType)
+      continue;
+
+    const bool SameNumberOfArguments =
+        Method->getNumParams() == MatchedOperator->getNumParams();
+    if (!SameNumberOfArguments)
+      continue;
+
+    for (unsigned a = 0; a < Method->getNumParams(); a++) {
+      const bool SameArgType =
+          Method->parameters()[a]->getOriginalType() ==
+          MatchedOperator->parameters()[a]->getOriginalType();
+      if (!SameArgType)
+        continue;
+    }
+
+    return Method;
   }
-  // TODO Add std::span with C++26
-  return Result;
+  return static_cast<CXXMethodDecl *>(nullptr);
 }
 
 void AvoidBoundsErrorsCheck::registerMatchers(MatchFinder *Finder) {
+  // Need a callExpr here to match CXXOperatorCallExpr ``(&a)->operator[](0)``
+  // and CXXMemberCallExpr ``a[0]``.
   Finder->addMatcher(
-      callExpr(callee(cxxMethodDecl(hasName("operator[]")).bind("f")))
-          .bind("x"),
+      callExpr(
+          callee(
+              cxxMethodDecl(hasOverloadedOperatorName("[]")).bind("operator")),
+          callee(cxxMethodDecl(hasParent(
+              cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")))))
+          .bind("caller"),
       this);
 }
 
 void AvoidBoundsErrorsCheck::check(const MatchFinder::MatchResult &Result) {
   const ASTContext &Context = *Result.Context;
   const SourceManager &Source = Context.getSourceManager();
-  const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("x");
-  const CXXMethodDecl *MatchedFunction = Result.Nodes.getNodeAs<CXXMethodDecl>("f");
-  const QualType Type = MatchedFunction->getThisType();
-  if (!isApplicable(Type)) {
-    return;
-  }
+  const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
+  const CXXMethodDecl *MatchedOperator =
+      Result.Nodes.getNodeAs<CXXMethodDecl>("operator");
+  const CXXRecordDecl *MatchedParent =
+      Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
 
-  // Get original code.
-  const SourceLocation b(MatchedExpr->getBeginLoc());
-  const SourceLocation e(MatchedExpr->getEndLoc());
-  const std::string OriginalCode =
-      Lexer::getSourceText(CharSourceRange::getTokenRange(b, e), Source,
-                           getLangOpts())
-          .str();
-  const auto Range = SourceRange(b, e);
+  const CXXMethodDecl *Alternative =
+      findAlternative(MatchedParent, MatchedOperator);
+  if (!Alternative)
+    return;
 
-  // Build replacement.
-  std::string NewCode = OriginalCode;
-  const auto BeginOpen = NewCode.find("[");
-  NewCode.replace(BeginOpen, 1, ".at(");
-  const auto BeginClose = NewCode.find("]");
-  NewCode.replace(BeginClose, 1, ")");
+  const SourceLocation AlternativeSource(Alternative->getBeginLoc());
 
-  diag(MatchedExpr->getBeginLoc(), "Do not use operator[], use at() instead.")
-      << FixItHint::CreateReplacement(Range, NewCode);
+  diag(MatchedExpr->getBeginLoc(),
+       "found possibly unsafe operator[], consider using at() instead");
+  diag(Alternative->getBeginLoc(), "alternative at() defined here",
+       DiagnosticIDs::Note);
 }
 
 } // namespace clang::tidy::cppcoreguidelines
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
index 23453b1f2df21..5e12e7d71790d 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
@@ -38,23 +38,22 @@ namespace json {
 std::array<int, 3> a;
 
 auto b = a[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
-// CHECK-FIXES: auto b = a.at(0);
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
 auto c = a[1+1];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
-// CHECK-FIXES: auto c = a.at(1+1);
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
 constexpr int index = 1;
 auto d = a[index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
-// CHECK-FIXES: auto d = a.at(index);
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
 
 int e(int index) {
   return a[index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: Do not use operator[], use at() instead. [cppcoreguidelines-avoid-bounds-errors]
-// CHECK-FIXES: return a.at(index);
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
 }
 
-auto f = a.at(0);
+auto f = (&a)->operator[](1);
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+
+auto g = a.at(0);
 
 std::unique_ptr<int> p;
 auto q = p[0];

>From ff305986c5c43284e462dcd1f4c301fe8ae293bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 10 Jun 2024 20:56:39 +0200
Subject: [PATCH 04/28] Rename AvoidBoundsErrorsCheck to
 PreferAtOverSubscriptOperatorCheck

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../clang-tidy/cppcoreguidelines/CMakeLists.txt  |  2 +-
 .../CppCoreGuidelinesTidyModule.cpp              |  6 +++---
 ...pp => PreferAtOverSubscriptOperatorCheck.cpp} |  9 +++++----
 ...ck.h => PreferAtOverSubscriptOperatorCheck.h} | 16 ++++++++--------
 clang-tools-extra/docs/ReleaseNotes.rst          |  6 +++---
 ...rst => prefer-at-over-subscript-operator.rst} |  4 ++--
 .../docs/clang-tidy/checks/list.rst              |  2 +-
 ...cpp => prefer-at-over-subscript-operator.cpp} | 12 ++++++------
 8 files changed, 29 insertions(+), 28 deletions(-)
 rename clang-tools-extra/clang-tidy/cppcoreguidelines/{AvoidBoundsErrorsCheck.cpp => PreferAtOverSubscriptOperatorCheck.cpp} (90%)
 rename clang-tools-extra/clang-tidy/cppcoreguidelines/{AvoidBoundsErrorsCheck.h => PreferAtOverSubscriptOperatorCheck.h} (60%)
 rename clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/{avoid-bounds-errors.rst => prefer-at-over-subscript-operator.rst} (83%)
 rename clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/{avoid-bounds-errors.cpp => prefer-at-over-subscript-operator.cpp} (67%)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
index 4972d20417928..fd436859ad04a 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -4,7 +4,6 @@ set(LLVM_LINK_COMPONENTS
   )
 
 add_clang_library(clangTidyCppCoreGuidelinesModule
-  AvoidBoundsErrorsCheck.cpp
   AvoidCapturingLambdaCoroutinesCheck.cpp
   AvoidConstOrRefDataMembersCheck.cpp
   AvoidDoWhileCheck.cpp
@@ -21,6 +20,7 @@ add_clang_library(clangTidyCppCoreGuidelinesModule
   NoMallocCheck.cpp
   NoSuspendWithLockCheck.cpp
   OwningMemoryCheck.cpp
+  PreferAtOverSubscriptOperatorCheck.cpp
   PreferMemberInitializerCheck.cpp
   ProBoundsArrayToPointerDecayCheck.cpp
   ProBoundsConstantArrayIndexCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index 525bbc7a42ada..565a99a865519 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -19,7 +19,6 @@
 #include "../performance/NoexceptMoveConstructorCheck.h"
 #include "../performance/NoexceptSwapCheck.h"
 #include "../readability/MagicNumbersCheck.h"
-#include "AvoidBoundsErrorsCheck.h"
 #include "AvoidCapturingLambdaCoroutinesCheck.h"
 #include "AvoidConstOrRefDataMembersCheck.h"
 #include "AvoidDoWhileCheck.h"
@@ -35,6 +34,7 @@
 #include "NoMallocCheck.h"
 #include "NoSuspendWithLockCheck.h"
 #include "OwningMemoryCheck.h"
+#include "PreferAtOverSubscriptOperatorCheck.h"
 #include "PreferMemberInitializerCheck.h"
 #include "ProBoundsArrayToPointerDecayCheck.h"
 #include "ProBoundsConstantArrayIndexCheck.h"
@@ -58,8 +58,6 @@ namespace cppcoreguidelines {
 class CppCoreGuidelinesModule : public ClangTidyModule {
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
-    CheckFactories.registerCheck<AvoidBoundsErrorsCheck>(
-        "cppcoreguidelines-avoid-bounds-errors");
     CheckFactories.registerCheck<AvoidCapturingLambdaCoroutinesCheck>(
         "cppcoreguidelines-avoid-capturing-lambda-coroutines");
     CheckFactories.registerCheck<modernize::AvoidCArraysCheck>(
@@ -105,6 +103,8 @@ class CppCoreGuidelinesModule : public ClangTidyModule {
         "cppcoreguidelines-non-private-member-variables-in-classes");
     CheckFactories.registerCheck<OwningMemoryCheck>(
         "cppcoreguidelines-owning-memory");
+    CheckFactories.registerCheck<PreferAtOverSubscriptOperatorCheck>(
+        "cppcoreguidelines-prefer-at-over-subscript-operator");
     CheckFactories.registerCheck<PreferMemberInitializerCheck>(
         "cppcoreguidelines-prefer-member-initializer");
     CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
similarity index 90%
rename from clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
rename to clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index f10b97820f4c7..64eaf8a1d4ebd 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -1,4 +1,4 @@
-//===--- AvoidBoundsErrorsCheck.cpp - clang-tidy --------------------------===//
+//===--- PreferAtOverSubscriptOperatorCheck.cpp - clang-tidy --------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "AvoidBoundsErrorsCheck.h"
+#include "PreferAtOverSubscriptOperatorCheck.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Lex/Lexer.h"
 
@@ -44,7 +44,7 @@ const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
   return static_cast<CXXMethodDecl *>(nullptr);
 }
 
-void AvoidBoundsErrorsCheck::registerMatchers(MatchFinder *Finder) {
+void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
   // Need a callExpr here to match CXXOperatorCallExpr ``(&a)->operator[](0)``
   // and CXXMemberCallExpr ``a[0]``.
   Finder->addMatcher(
@@ -57,7 +57,8 @@ void AvoidBoundsErrorsCheck::registerMatchers(MatchFinder *Finder) {
       this);
 }
 
-void AvoidBoundsErrorsCheck::check(const MatchFinder::MatchResult &Result) {
+void PreferAtOverSubscriptOperatorCheck::check(
+    const MatchFinder::MatchResult &Result) {
   const ASTContext &Context = *Result.Context;
   const SourceManager &Source = Context.getSourceManager();
   const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
similarity index 60%
rename from clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
rename to clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
index 12c7852877123..eb6e3a021e1b6 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidBoundsErrorsCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
@@ -1,4 +1,5 @@
-//===--- AvoidBoundsErrorsCheck.h - clang-tidy ------------------*- C++ -*-===//
+//===--- PreferAtOverSubscriptOperatorCheck.h - clang-tidy ------*- C++ -*-===//
+//===--- PreferMemberInitializerCheck.h - clang-tidy ------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
 
 #include "../ClangTidyCheck.h"
 
@@ -18,11 +19,10 @@ namespace clang::tidy::cppcoreguidelines {
 /// See
 /// https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors
 /// For the user-facing documentation see:
-/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.html
-class AvoidBoundsErrorsCheck : public ClangTidyCheck {
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.html
+class PreferAtOverSubscriptOperatorCheck : public ClangTidyCheck {
 public:
-  AvoidBoundsErrorsCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  PreferAtOverSubscriptOperatorCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus;
   }
@@ -32,4 +32,4 @@ class AvoidBoundsErrorsCheck : public ClangTidyCheck {
 
 } // namespace clang::tidy::cppcoreguidelines
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_AVOIDBOUNDSERRORSCHECK_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 0106b6ea732db..c88e59e453265 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -160,10 +160,10 @@ New checks
   Replaces nested ``std::min`` and ``std::max`` calls with an initializer list
   where applicable.
 
-- New :doc:`cppcoreguidelines-avoid-bounds-errors
-  <clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors>` check.
+- New :doc:`cppcoreguidelines-prefer-at-over-subscript-operator
+  <clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator>` check.
 
-  Flags the unsafe ``operator[]`` and replaces it with ``at()``.
+  Flags the unsafe ``operator[]`` and suggests replacing it with ``at()``.
 
 - New :doc:`modernize-use-designated-initializers
   <clang-tidy/checks/modernize/use-designated-initializers>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
similarity index 83%
rename from clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
rename to clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 13683ee9b5a46..183175b596668 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/avoid-bounds-errors.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -1,6 +1,6 @@
-.. title:: clang-tidy - cppcoreguidelines-avoid-bounds-errors
+.. title:: clang-tidy - cppcoreguidelines-prefer-at-over-subscript-operator
 
-cppcoreguidelines-avoid-bounds-errors
+cppcoreguidelines-prefer-at-over-subscript-operator
 =====================================
 
 This check flags all uses of ``operator[]`` on ``std::vector``, ``std::array``, ``std::deque``, ``std::map``, ``std::unordered_map``, and ``std::flat_map`` and suggests to replace it with ``at()``.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index d9c72bedfb95b..d83dad31b3547 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -174,7 +174,6 @@ Clang-Tidy Checks
    :doc:`cert-oop58-cpp <cert/oop58-cpp>`,
    :doc:`concurrency-mt-unsafe <concurrency/mt-unsafe>`,
    :doc:`concurrency-thread-canceltype-asynchronous <concurrency/thread-canceltype-asynchronous>`,
-   :doc:`cppcoreguidelines-avoid-bounds-errors <cppcoreguidelines/avoid-bounds-errors>`, "Yes"
    :doc:`cppcoreguidelines-avoid-capturing-lambda-coroutines <cppcoreguidelines/avoid-capturing-lambda-coroutines>`,
    :doc:`cppcoreguidelines-avoid-const-or-ref-data-members <cppcoreguidelines/avoid-const-or-ref-data-members>`,
    :doc:`cppcoreguidelines-avoid-do-while <cppcoreguidelines/avoid-do-while>`,
@@ -190,6 +189,7 @@ Clang-Tidy Checks
    :doc:`cppcoreguidelines-no-malloc <cppcoreguidelines/no-malloc>`,
    :doc:`cppcoreguidelines-no-suspend-with-lock <cppcoreguidelines/no-suspend-with-lock>`,
    :doc:`cppcoreguidelines-owning-memory <cppcoreguidelines/owning-memory>`,
+   :doc:`cppcoreguidelines-prefer-at-over-subscript-operator <cppcoreguidelines/prefer-at-over-subscript-operator>`,
    :doc:`cppcoreguidelines-prefer-member-initializer <cppcoreguidelines/prefer-member-initializer>`, "Yes"
    :doc:`cppcoreguidelines-pro-bounds-array-to-pointer-decay <cppcoreguidelines/pro-bounds-array-to-pointer-decay>`,
    :doc:`cppcoreguidelines-pro-bounds-constant-array-index <cppcoreguidelines/pro-bounds-constant-array-index>`, "Yes"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
similarity index 67%
rename from clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
rename to clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
index 5e12e7d71790d..45071f8f9f207 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/avoid-bounds-errors.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
@@ -34,24 +34,24 @@ namespace json {
 } // namespace json
 
 
-// RUN: %check_clang_tidy %s cppcoreguidelines-avoid-bounds-errors %t
+// RUN: %check_clang_tidy %s cppcoreguidelines-prefer-at-over-subscript-operator %t
 std::array<int, 3> a;
 
 auto b = a[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 auto c = a[1+1];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 constexpr int index = 1;
 auto d = a[index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 
 int e(int index) {
   return a[index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 }
 
 auto f = (&a)->operator[](1);
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-avoid-bounds-errors]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 
 auto g = a.at(0);
 

>From ce18fe6d17385d2ad5b4d3e05661af660e6575cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 10 Jun 2024 22:14:54 +0200
Subject: [PATCH 05/28] Add a user-customizable mechanism for excluding classes
 from the analysis

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../PreferAtOverSubscriptOperatorCheck.cpp    | 49 +++++++++++++++++--
 .../PreferAtOverSubscriptOperatorCheck.h      |  5 ++
 .../prefer-at-over-subscript-operator.cpp     | 36 +++++++++++++-
 3 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index 64eaf8a1d4ebd..d7cdbc59d3941 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -7,13 +7,52 @@
 //===----------------------------------------------------------------------===//
 
 #include "PreferAtOverSubscriptOperatorCheck.h"
+#include "../utils/OptionsUtils.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
-#include "clang/Lex/Lexer.h"
+#include "llvm/ADT/StringRef.h"
+#include <algorithm>
+#include <numeric>
 
 using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
+static constexpr std::array<llvm::StringRef, 3> DefaultExclusions = {
+    llvm::StringRef("std::map"), llvm::StringRef("std::unordered_map"),
+    llvm::StringRef("std::flat_map")};
+
+PreferAtOverSubscriptOperatorCheck::PreferAtOverSubscriptOperatorCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context) {
+
+  ExcludedClasses = clang::tidy::utils::options::parseStringList(
+      Options.get("ExcludeClasses", ""));
+  ExcludedClasses.insert(ExcludedClasses.end(), DefaultExclusions.begin(),
+                         DefaultExclusions.end());
+}
+
+void PreferAtOverSubscriptOperatorCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+
+  if (ExcludedClasses.size() == DefaultExclusions.size()) {
+    Options.store(Opts, "ExcludeClasses", "");
+    return;
+  }
+
+  // Sum up the sizes of the defaults ( + semicolons), so we can remove them
+  // from the saved options
+  size_t DefaultsStringLength =
+      std::transform_reduce(DefaultExclusions.begin(), DefaultExclusions.end(),
+                            DefaultExclusions.size(), std::plus<>(),
+                            [](llvm::StringRef Name) { return Name.size(); });
+
+  std::string Serialized =
+      clang::tidy::utils::options::serializeStringList(ExcludedClasses);
+
+  Options.store(Opts, "ExcludeClasses",
+                Serialized.substr(0, Serialized.size() - DefaultsStringLength));
+}
+
 const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
                                      const CXXMethodDecl *MatchedOperator) {
   for (const CXXMethodDecl *Method : MatchedParent->methods()) {
@@ -67,13 +106,17 @@ void PreferAtOverSubscriptOperatorCheck::check(
   const CXXRecordDecl *MatchedParent =
       Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
 
+  std::string ClassIdentifier = MatchedParent->getQualifiedNameAsString();
+
+  if (std::find(ExcludedClasses.begin(), ExcludedClasses.end(),
+                ClassIdentifier) != ExcludedClasses.end())
+    return;
+
   const CXXMethodDecl *Alternative =
       findAlternative(MatchedParent, MatchedOperator);
   if (!Alternative)
     return;
 
-  const SourceLocation AlternativeSource(Alternative->getBeginLoc());
-
   diag(MatchedExpr->getBeginLoc(),
        "found possibly unsafe operator[], consider using at() instead");
   diag(Alternative->getBeginLoc(), "alternative at() defined here",
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
index eb6e3a021e1b6..f2450a7ab3470 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
@@ -28,6 +28,11 @@ class PreferAtOverSubscriptOperatorCheck : public ClangTidyCheck {
   }
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+
+private:
+  // A list of class names that are excluded from the warning
+  std::vector<llvm::StringRef> ExcludedClasses;
 };
 
 } // namespace clang::tidy::cppcoreguidelines
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
index 45071f8f9f207..7da6c31556969 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
@@ -34,7 +34,30 @@ namespace json {
 } // namespace json
 
 
-// RUN: %check_clang_tidy %s cppcoreguidelines-prefer-at-over-subscript-operator %t
+class ExcludedClass1 {
+  public:
+    int operator[](unsigned i) {
+      return 1;
+    }
+    int at(unsigned i) {
+      return 1;
+    }
+};
+
+class ExcludedClass2 {
+  public:
+    int operator[](unsigned i) {
+      return 1;
+    }
+    int at(unsigned i) {
+      return 1;
+    }
+};
+
+
+// RUN: %check_clang_tidy %s \
+// RUN: cppcoreguidelines-prefer-at-over-subscript-operator %t -- \
+// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "ExcludedClass1;ExcludedClass2"}}'
 std::array<int, 3> a;
 
 auto b = a[0];
@@ -63,3 +86,14 @@ auto t = s[0];
 
 json::node<int> n;
 auto m = n[0];
+
+//explicitely excluded classes / struct / template
+ExcludedClass1 E1;
+auto x1 = E1[0];
+
+ExcludedClass2 E2;
+auto x2 = E1[0];
+
+std::map<int,int> TestMap;
+auto y = TestMap[0];
+

>From 28d26b558d2ef9f29c8a1afbf52d32c2d0258d43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 10 Jun 2024 22:16:49 +0200
Subject: [PATCH 06/28] Update the documentation

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../prefer-at-over-subscript-operator.rst     | 22 ++++++++++++++-----
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 183175b596668..42a2100f32582 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -3,8 +3,7 @@
 cppcoreguidelines-prefer-at-over-subscript-operator
 =====================================
 
-This check flags all uses of ``operator[]`` on ``std::vector``, ``std::array``, ``std::deque``, ``std::map``, ``std::unordered_map``, and ``std::flat_map`` and suggests to replace it with ``at()``.
-Note that ``std::span`` and ``std::mdspan`` do not support ``at()`` as of C++23, so the use of ``operator[]`` is not flagged.
+This check flags all uses of ``operator[]`` where an equivalent (same parameter and return types) ``at()`` method exists and suggest using that instead.
 
 For example the code
 
@@ -12,10 +11,21 @@ For example the code
   std::array<int, 3> a;
   int b = a[4];
 
-will be replaced by 
+will generate a warning but 
 
 .. code-block:: c++
-  std::vector<int, 3> a;
-  int b = a.at(4);
+  std::unique_ptr<int> a;
+  int b = a[0];
 
-This check enforces the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.
+will not.
+
+The classes ``std::map``, ``std::unordered_map`` and ``std::flat_map`` are excluded from this check, because for them the subscript operator has a defined behaviour when a key does not exist (inserting a new element).
+
+Options
+-------
+
+.. option:: ExcludeClasses
+
+    Semicolon-delimited list of class names that should additionally be excluded from this check. By default empty. 
+
+This check enforces part of the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.

>From e7ea897c0a7cec86a103f890f459d287a5c00868 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 10 Jun 2024 21:43:23 +0200
Subject: [PATCH 07/28] Add remaining tests requested by @PiotrZSL

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../prefer-at-over-subscript-operator.cpp     | 53 +++++++++++++++++--
 1 file changed, 48 insertions(+), 5 deletions(-)

diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
index 7da6c31556969..cc7088bffeda9 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
@@ -9,6 +9,16 @@ namespace std {
     }
   };
 
+  template<typename T, typename V>
+  struct map {
+    T operator[](unsigned i) {
+      return T{1};
+    }
+    T at(unsigned i) {
+      return T{1};
+    }
+  };
+
   template<typename T>
   struct unique_ptr {
     T operator[](unsigned i) {
@@ -33,6 +43,7 @@ namespace json {
   };
 } // namespace json
 
+struct SubClass : std::array<int, 3> {};
 
 class ExcludedClass1 {
   public:
@@ -62,15 +73,17 @@ std::array<int, 3> a;
 
 auto b = a[0];
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
 auto c = a[1+1];
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
-constexpr int index = 1;
-auto d = a[index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 
-int e(int index) {
-  return a[index];
+constexpr int Index = 1;
+auto d = a[Index];
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+int e(int Ind) {
+  return a[Ind];
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
 }
 
 auto f = (&a)->operator[](1);
@@ -87,6 +100,24 @@ auto t = s[0];
 json::node<int> n;
 auto m = n[0];
 
+SubClass Sub;
+auto r = Sub[0];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+typedef std::array<int, 3> ar;
+ar BehindDef;
+auto u = BehindDef[0];
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+template<typename T> int TestTemplate(T t){
+  return t[0];
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+}
+
+auto v = TestTemplate<>(a);
+auto w = TestTemplate<>(p);
+
 //explicitely excluded classes / struct / template
 ExcludedClass1 E1;
 auto x1 = E1[0];
@@ -97,3 +128,15 @@ auto x2 = E1[0];
 std::map<int,int> TestMap;
 auto y = TestMap[0];
 
+#define SUBSCRIPT_BEHIND_MARCO(x) a[x]
+#define ARG_BEHIND_MACRO 0
+#define OBJECT_BEHIND_MACRO a
+
+auto m1 = SUBSCRIPT_BEHIND_MARCO(0);
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+auto m2 = a[ARG_BEHIND_MACRO];
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+
+auto m3 = OBJECT_BEHIND_MACRO[0];
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]

>From 19793edbc3d96af77d49d06037fabb043af5b370 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 10 Jun 2024 22:22:21 +0200
Subject: [PATCH 08/28] Remove unused and rename variables

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../PreferAtOverSubscriptOperatorCheck.cpp                | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index d7cdbc59d3941..dc036e23e2af1 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -70,10 +70,10 @@ const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
     if (!SameNumberOfArguments)
       continue;
 
-    for (unsigned a = 0; a < Method->getNumParams(); a++) {
+    for (unsigned ArgInd = 0; ArgInd < Method->getNumParams(); ArgInd++) {
       const bool SameArgType =
-          Method->parameters()[a]->getOriginalType() ==
-          MatchedOperator->parameters()[a]->getOriginalType();
+          Method->parameters()[ArgInd]->getOriginalType() ==
+          MatchedOperator->parameters()[ArgInd]->getOriginalType();
       if (!SameArgType)
         continue;
     }
@@ -98,8 +98,6 @@ void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
 
 void PreferAtOverSubscriptOperatorCheck::check(
     const MatchFinder::MatchResult &Result) {
-  const ASTContext &Context = *Result.Context;
-  const SourceManager &Source = Context.getSourceManager();
   const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
   const CXXMethodDecl *MatchedOperator =
       Result.Nodes.getNodeAs<CXXMethodDecl>("operator");

>From 514f86783699534d6e078a44356d862b59484c61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Wed, 12 Jun 2024 16:56:40 +0200
Subject: [PATCH 09/28] Update types in
 PreferAtOverSubscriptOperatorCheck::check()

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../PreferAtOverSubscriptOperatorCheck.cpp                 | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index dc036e23e2af1..0924fda164b4a 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -98,11 +98,10 @@ void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
 
 void PreferAtOverSubscriptOperatorCheck::check(
     const MatchFinder::MatchResult &Result) {
-  const CallExpr *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
-  const CXXMethodDecl *MatchedOperator =
+  const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
+  const auto *MatchedOperator =
       Result.Nodes.getNodeAs<CXXMethodDecl>("operator");
-  const CXXRecordDecl *MatchedParent =
-      Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
+  const auto *MatchedParent = Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
 
   std::string ClassIdentifier = MatchedParent->getQualifiedNameAsString();
 

>From e5317255c9affc6e78f228561996b6e9789b5c6a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Wed, 12 Jun 2024 17:00:00 +0200
Subject: [PATCH 10/28] Fix length of underline in
 prefer-at-over-subscript-operator.rst

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/prefer-at-over-subscript-operator.rst     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 42a2100f32582..96c71931ff2a3 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -1,7 +1,7 @@
 .. title:: clang-tidy - cppcoreguidelines-prefer-at-over-subscript-operator
 
 cppcoreguidelines-prefer-at-over-subscript-operator
-=====================================
+===================================================
 
 This check flags all uses of ``operator[]`` where an equivalent (same parameter and return types) ``at()`` method exists and suggest using that instead.
 

>From 872ebecd627a72596e62867ab85ba27e319cfe99 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Wed, 12 Jun 2024 17:02:33 +0200
Subject: [PATCH 11/28] Enforce 80 char column width in
 prefer-at-over-subscript-operator.rst

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../prefer-at-over-subscript-operator.rst          | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 96c71931ff2a3..873564d12dd6b 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -3,7 +3,8 @@
 cppcoreguidelines-prefer-at-over-subscript-operator
 ===================================================
 
-This check flags all uses of ``operator[]`` where an equivalent (same parameter and return types) ``at()`` method exists and suggest using that instead.
+This check flags all uses of ``operator[]`` where an equivalent (same parameter
+and return types) ``at()`` method exists and suggest using that instead.
 
 For example the code
 
@@ -19,13 +20,18 @@ will generate a warning but
 
 will not.
 
-The classes ``std::map``, ``std::unordered_map`` and ``std::flat_map`` are excluded from this check, because for them the subscript operator has a defined behaviour when a key does not exist (inserting a new element).
+The classes ``std::map``, ``std::unordered_map`` and ``std::flat_map`` are
+excluded from this check, because for them the subscript operator has a defined
+behaviour when a key does not exist (inserting a new element).
 
 Options
 -------
 
 .. option:: ExcludeClasses
 
-    Semicolon-delimited list of class names that should additionally be excluded from this check. By default empty. 
+    Semicolon-delimited list of class names that should additionally be
+    excluded from this check. By default empty.
 
-This check enforces part of the `SL.con.3 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>` guideline.
+This check enforces part of the `SL.con.3
+<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>`
+guideline.

>From 27ce22d0ec43b9e11167286db7b15b5c936e5de8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Thu, 13 Jun 2024 10:18:58 +0200
Subject: [PATCH 12/28] Synchronise prefer-at-over-subscript-operator.rst with
 ReleaseNotes.rst

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/prefer-at-over-subscript-operator.rst    | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 873564d12dd6b..7999cd4baeb7c 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -3,8 +3,7 @@
 cppcoreguidelines-prefer-at-over-subscript-operator
 ===================================================
 
-This check flags all uses of ``operator[]`` where an equivalent (same parameter
-and return types) ``at()`` method exists and suggest using that instead.
+Flags the unsafe ``operator[]`` and suggests replacing it with ``at()``.
 
 For example the code
 

>From e905c98deb907d879e2a58a89a1d97737b92865c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 17 Jun 2024 12:03:57 +0200
Subject: [PATCH 13/28] Move RUN lines to the top of
 prefer-at-over-subscript-operator.cpp

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../prefer-at-over-subscript-operator.cpp                 | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
index cc7088bffeda9..76b84bf860cb6 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
@@ -1,3 +1,7 @@
+// RUN: %check_clang_tidy %s \
+// RUN: cppcoreguidelines-prefer-at-over-subscript-operator %t -- \
+// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "ExcludedClass1;ExcludedClass2"}}'
+
 namespace std {
   template<typename T, unsigned size>
   struct array {
@@ -65,10 +69,6 @@ class ExcludedClass2 {
     }
 };
 
-
-// RUN: %check_clang_tidy %s \
-// RUN: cppcoreguidelines-prefer-at-over-subscript-operator %t -- \
-// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "ExcludedClass1;ExcludedClass2"}}'
 std::array<int, 3> a;
 
 auto b = a[0];

>From 111f71fa069ff474cc31229f5a8cb1dfd3d663cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 17 Jun 2024 12:05:10 +0200
Subject: [PATCH 14/28] Add an empty lien after each `code-block` in
 prefer-at-over-subscript-operator.rst

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/prefer-at-over-subscript-operator.rst     | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
index 7999cd4baeb7c..f3577cb5b15f0 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
@@ -8,12 +8,14 @@ Flags the unsafe ``operator[]`` and suggests replacing it with ``at()``.
 For example the code
 
 .. code-block:: c++
+
   std::array<int, 3> a;
   int b = a[4];
 
 will generate a warning but 
 
 .. code-block:: c++
+
   std::unique_ptr<int> a;
   int b = a[0];
 

>From 4da1da0eeadeb51f8d435932dccc2b28b688f239 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 17 Jun 2024 12:08:56 +0200
Subject: [PATCH 15/28] Use ofClass() instead of hasParent() in
 PreferAtOverSubscriptOperatorCheck.cpp

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index 0924fda164b4a..d047c0b2332d1 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -90,8 +90,8 @@ void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
       callExpr(
           callee(
               cxxMethodDecl(hasOverloadedOperatorName("[]")).bind("operator")),
-          callee(cxxMethodDecl(hasParent(
-              cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")))))
+          callee(cxxMethodDecl(
+              ofClass(cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")))))
           .bind("caller"),
       this);
 }

>From 5098f65dc68e33ef854335e243b9570c4b0cf696 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 17 Jun 2024 12:42:33 +0200
Subject: [PATCH 16/28] Use matchesAnyListedName() in matcher instead of
 explicit std::find() check

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../PreferAtOverSubscriptOperatorCheck.cpp        | 15 +++++----------
 .../prefer-at-over-subscript-operator.cpp         |  2 +-
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index d047c0b2332d1..82a957241042a 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -7,10 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "PreferAtOverSubscriptOperatorCheck.h"
+#include "../utils/Matchers.h"
 #include "../utils/OptionsUtils.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "llvm/ADT/StringRef.h"
-#include <algorithm>
 #include <numeric>
 
 using namespace clang::ast_matchers;
@@ -18,8 +18,8 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::cppcoreguidelines {
 
 static constexpr std::array<llvm::StringRef, 3> DefaultExclusions = {
-    llvm::StringRef("std::map"), llvm::StringRef("std::unordered_map"),
-    llvm::StringRef("std::flat_map")};
+    llvm::StringRef("::std::map"), llvm::StringRef("::std::unordered_map"),
+    llvm::StringRef("::std::flat_map")};
 
 PreferAtOverSubscriptOperatorCheck::PreferAtOverSubscriptOperatorCheck(
     StringRef Name, ClangTidyContext *Context)
@@ -91,7 +91,8 @@ void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
           callee(
               cxxMethodDecl(hasOverloadedOperatorName("[]")).bind("operator")),
           callee(cxxMethodDecl(
-              ofClass(cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")))))
+              ofClass(cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")),
+              unless(matchers::matchesAnyListedName(ExcludedClasses)))))
           .bind("caller"),
       this);
 }
@@ -103,12 +104,6 @@ void PreferAtOverSubscriptOperatorCheck::check(
       Result.Nodes.getNodeAs<CXXMethodDecl>("operator");
   const auto *MatchedParent = Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
 
-  std::string ClassIdentifier = MatchedParent->getQualifiedNameAsString();
-
-  if (std::find(ExcludedClasses.begin(), ExcludedClasses.end(),
-                ClassIdentifier) != ExcludedClasses.end())
-    return;
-
   const CXXMethodDecl *Alternative =
       findAlternative(MatchedParent, MatchedOperator);
   if (!Alternative)
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
index 76b84bf860cb6..4ae17688cb9e2 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
@@ -1,6 +1,6 @@
 // RUN: %check_clang_tidy %s \
 // RUN: cppcoreguidelines-prefer-at-over-subscript-operator %t -- \
-// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "ExcludedClass1;ExcludedClass2"}}'
+// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "::ExcludedClass1;::ExcludedClass2"}}'
 
 namespace std {
   template<typename T, unsigned size>

>From da428089d6cfdfaf02b563a325ab8d900b62de56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Mon, 17 Jun 2024 14:23:35 +0200
Subject: [PATCH 17/28] Match source range of expression in warnings emitted by
 PreferAtOverSubscriptOperatorCheck

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../PreferAtOverSubscriptOperatorCheck.cpp                  | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
index 82a957241042a..5a5704deae14f 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
@@ -110,9 +110,11 @@ void PreferAtOverSubscriptOperatorCheck::check(
     return;
 
   diag(MatchedExpr->getBeginLoc(),
-       "found possibly unsafe operator[], consider using at() instead");
+       "found possibly unsafe operator[], consider using at() instead")
+      << MatchedExpr->getSourceRange();
   diag(Alternative->getBeginLoc(), "alternative at() defined here",
-       DiagnosticIDs::Note);
+       DiagnosticIDs::Note)
+      << Alternative->getSourceRange();
 }
 
 } // namespace clang::tidy::cppcoreguidelines

>From e4a4a694f0068d57b417adacd5c9a4595269c752 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Fri, 21 Jun 2024 10:42:45 +0200
Subject: [PATCH 18/28] PreferAtOverSubscriptOpterator ->
 ProBoundsAvoidUncheckedContainerAccesses

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/CMakeLists.txt          |  2 +-
 .../CppCoreGuidelinesTidyModule.cpp           |  6 ++---
 ...BoundsAvoidUncheckedContainerAccesses.cpp} | 16 +++++++-----
 ...roBoundsAvoidUncheckedContainerAccesses.h} | 15 ++++++-----
 clang-tools-extra/docs/ReleaseNotes.rst       |  4 +--
 ...ds-avoid-unchecked-container-accesses.rst} |  4 +--
 .../docs/clang-tidy/checks/list.rst           |  2 +-
 ...ds-avoid-unchecked-container-accesses.cpp} | 26 +++++++++----------
 8 files changed, 39 insertions(+), 36 deletions(-)
 rename clang-tools-extra/clang-tidy/cppcoreguidelines/{PreferAtOverSubscriptOperatorCheck.cpp => ProBoundsAvoidUncheckedContainerAccesses.cpp} (88%)
 rename clang-tools-extra/clang-tidy/cppcoreguidelines/{PreferAtOverSubscriptOperatorCheck.h => ProBoundsAvoidUncheckedContainerAccesses.h} (67%)
 rename clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/{prefer-at-over-subscript-operator.rst => pro-bounds-avoid-unchecked-container-accesses.rst} (84%)
 rename clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/{prefer-at-over-subscript-operator.cpp => pro-bounds-avoid-unchecked-container-accesses.cpp} (82%)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
index fd436859ad04a..aa7bdd86bc795 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -20,9 +20,9 @@ add_clang_library(clangTidyCppCoreGuidelinesModule
   NoMallocCheck.cpp
   NoSuspendWithLockCheck.cpp
   OwningMemoryCheck.cpp
-  PreferAtOverSubscriptOperatorCheck.cpp
   PreferMemberInitializerCheck.cpp
   ProBoundsArrayToPointerDecayCheck.cpp
+  ProBoundsAvoidUncheckedContainerAccesses.cpp
   ProBoundsConstantArrayIndexCheck.cpp
   ProBoundsPointerArithmeticCheck.cpp
   ProTypeConstCastCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index 565a99a865519..c154f4eec9373 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -34,9 +34,9 @@
 #include "NoMallocCheck.h"
 #include "NoSuspendWithLockCheck.h"
 #include "OwningMemoryCheck.h"
-#include "PreferAtOverSubscriptOperatorCheck.h"
 #include "PreferMemberInitializerCheck.h"
 #include "ProBoundsArrayToPointerDecayCheck.h"
+#include "ProBoundsAvoidUncheckedContainerAccesses.h"
 #include "ProBoundsConstantArrayIndexCheck.h"
 #include "ProBoundsPointerArithmeticCheck.h"
 #include "ProTypeConstCastCheck.h"
@@ -103,12 +103,12 @@ class CppCoreGuidelinesModule : public ClangTidyModule {
         "cppcoreguidelines-non-private-member-variables-in-classes");
     CheckFactories.registerCheck<OwningMemoryCheck>(
         "cppcoreguidelines-owning-memory");
-    CheckFactories.registerCheck<PreferAtOverSubscriptOperatorCheck>(
-        "cppcoreguidelines-prefer-at-over-subscript-operator");
     CheckFactories.registerCheck<PreferMemberInitializerCheck>(
         "cppcoreguidelines-prefer-member-initializer");
     CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
         "cppcoreguidelines-pro-bounds-array-to-pointer-decay");
+    CheckFactories.registerCheck<ProBoundsAvoidUncheckedContainerAccesses>(
+        "cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses");
     CheckFactories.registerCheck<ProBoundsConstantArrayIndexCheck>(
         "cppcoreguidelines-pro-bounds-constant-array-index");
     CheckFactories.registerCheck<ProBoundsPointerArithmeticCheck>(
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
similarity index 88%
rename from clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
rename to clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 5a5704deae14f..19a52d0e565fa 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -1,4 +1,4 @@
-//===--- PreferAtOverSubscriptOperatorCheck.cpp - clang-tidy --------------===//
+//===--- ProBoundsAvoidUncheckedContainerAccesses.cpp - clang-tidy --------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "PreferAtOverSubscriptOperatorCheck.h"
+#include "ProBoundsAvoidUncheckedContainerAccesses.h"
 #include "../utils/Matchers.h"
 #include "../utils/OptionsUtils.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
@@ -21,8 +21,9 @@ static constexpr std::array<llvm::StringRef, 3> DefaultExclusions = {
     llvm::StringRef("::std::map"), llvm::StringRef("::std::unordered_map"),
     llvm::StringRef("::std::flat_map")};
 
-PreferAtOverSubscriptOperatorCheck::PreferAtOverSubscriptOperatorCheck(
-    StringRef Name, ClangTidyContext *Context)
+ProBoundsAvoidUncheckedContainerAccesses::
+    ProBoundsAvoidUncheckedContainerAccesses(StringRef Name,
+                                             ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context) {
 
   ExcludedClasses = clang::tidy::utils::options::parseStringList(
@@ -31,7 +32,7 @@ PreferAtOverSubscriptOperatorCheck::PreferAtOverSubscriptOperatorCheck(
                          DefaultExclusions.end());
 }
 
-void PreferAtOverSubscriptOperatorCheck::storeOptions(
+void ProBoundsAvoidUncheckedContainerAccesses::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
 
   if (ExcludedClasses.size() == DefaultExclusions.size()) {
@@ -83,7 +84,8 @@ const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
   return static_cast<CXXMethodDecl *>(nullptr);
 }
 
-void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
+void ProBoundsAvoidUncheckedContainerAccesses::registerMatchers(
+    MatchFinder *Finder) {
   // Need a callExpr here to match CXXOperatorCallExpr ``(&a)->operator[](0)``
   // and CXXMemberCallExpr ``a[0]``.
   Finder->addMatcher(
@@ -97,7 +99,7 @@ void PreferAtOverSubscriptOperatorCheck::registerMatchers(MatchFinder *Finder) {
       this);
 }
 
-void PreferAtOverSubscriptOperatorCheck::check(
+void ProBoundsAvoidUncheckedContainerAccesses::check(
     const MatchFinder::MatchResult &Result) {
   const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
   const auto *MatchedOperator =
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
similarity index 67%
rename from clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
rename to clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
index f2450a7ab3470..33abbef5e8243 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferAtOverSubscriptOperatorCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
@@ -1,4 +1,4 @@
-//===--- PreferAtOverSubscriptOperatorCheck.h - clang-tidy ------*- C++ -*-===//
+//===--- ProBoundsAvoidUncheckedContainerAccesses.h - clang-tidy *- C++ -*-===//
 //===--- PreferMemberInitializerCheck.h - clang-tidy ------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_AVOID_UNCHECKED_CONTAINER_ACCESSES_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_AVOID_UNCHECKED_CONTAINER_ACCESSES_H
 
 #include "../ClangTidyCheck.h"
 
@@ -19,10 +19,11 @@ namespace clang::tidy::cppcoreguidelines {
 /// See
 /// https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors
 /// For the user-facing documentation see:
-/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.html
-class PreferAtOverSubscriptOperatorCheck : public ClangTidyCheck {
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.html
+class ProBoundsAvoidUncheckedContainerAccesses : public ClangTidyCheck {
 public:
-  PreferAtOverSubscriptOperatorCheck(StringRef Name, ClangTidyContext *Context);
+  ProBoundsAvoidUncheckedContainerAccesses(StringRef Name,
+                                           ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus;
   }
@@ -37,4 +38,4 @@ class PreferAtOverSubscriptOperatorCheck : public ClangTidyCheck {
 
 } // namespace clang::tidy::cppcoreguidelines
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PREFERATOVERSUBSCRIPTOPERATORCHECK_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_AVOID_UNCHECKED_CONTAINER_ACCESSES_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index c88e59e453265..cb43840a54806 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -160,8 +160,8 @@ New checks
   Replaces nested ``std::min`` and ``std::max`` calls with an initializer list
   where applicable.
 
-- New :doc:`cppcoreguidelines-prefer-at-over-subscript-operator
-  <clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator>` check.
+- New :doc:`cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses
+  <clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses>` check.
 
   Flags the unsafe ``operator[]`` and suggests replacing it with ``at()``.
 
diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
similarity index 84%
rename from clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
rename to clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
index f3577cb5b15f0..616882738653d 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-at-over-subscript-operator.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
@@ -1,6 +1,6 @@
-.. title:: clang-tidy - cppcoreguidelines-prefer-at-over-subscript-operator
+.. title:: clang-tidy - cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses
 
-cppcoreguidelines-prefer-at-over-subscript-operator
+cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses
 ===================================================
 
 Flags the unsafe ``operator[]`` and suggests replacing it with ``at()``.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index d83dad31b3547..06445e03b2022 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -189,9 +189,9 @@ Clang-Tidy Checks
    :doc:`cppcoreguidelines-no-malloc <cppcoreguidelines/no-malloc>`,
    :doc:`cppcoreguidelines-no-suspend-with-lock <cppcoreguidelines/no-suspend-with-lock>`,
    :doc:`cppcoreguidelines-owning-memory <cppcoreguidelines/owning-memory>`,
-   :doc:`cppcoreguidelines-prefer-at-over-subscript-operator <cppcoreguidelines/prefer-at-over-subscript-operator>`,
    :doc:`cppcoreguidelines-prefer-member-initializer <cppcoreguidelines/prefer-member-initializer>`, "Yes"
    :doc:`cppcoreguidelines-pro-bounds-array-to-pointer-decay <cppcoreguidelines/pro-bounds-array-to-pointer-decay>`,
+   :doc:`cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses <cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses>`,
    :doc:`cppcoreguidelines-pro-bounds-constant-array-index <cppcoreguidelines/pro-bounds-constant-array-index>`, "Yes"
    :doc:`cppcoreguidelines-pro-bounds-pointer-arithmetic <cppcoreguidelines/pro-bounds-pointer-arithmetic>`,
    :doc:`cppcoreguidelines-pro-type-const-cast <cppcoreguidelines/pro-type-const-cast>`,
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
similarity index 82%
rename from clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
rename to clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
index 4ae17688cb9e2..1a7a7fba7d8a2 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-at-over-subscript-operator.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
@@ -1,6 +1,6 @@
 // RUN: %check_clang_tidy %s \
-// RUN: cppcoreguidelines-prefer-at-over-subscript-operator %t -- \
-// RUN: -config='{CheckOptions: {cppcoreguidelines-prefer-at-over-subscript-operator.ExcludeClasses: "::ExcludedClass1;::ExcludedClass2"}}'
+// RUN: cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses %t -- \
+// RUN: -config='{CheckOptions: {cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses.ExcludeClasses: "::ExcludedClass1;::ExcludedClass2"}}'
 
 namespace std {
   template<typename T, unsigned size>
@@ -72,22 +72,22 @@ class ExcludedClass2 {
 std::array<int, 3> a;
 
 auto b = a[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto c = a[1+1];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 constexpr int Index = 1;
 auto d = a[Index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 int e(int Ind) {
   return a[Ind];
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 }
 
 auto f = (&a)->operator[](1);
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto g = a.at(0);
 
@@ -102,16 +102,16 @@ auto m = n[0];
 
 SubClass Sub;
 auto r = Sub[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 typedef std::array<int, 3> ar;
 ar BehindDef;
 auto u = BehindDef[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 template<typename T> int TestTemplate(T t){
   return t[0];
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 }
 
@@ -133,10 +133,10 @@ auto y = TestMap[0];
 #define OBJECT_BEHIND_MACRO a
 
 auto m1 = SUBSCRIPT_BEHIND_MARCO(0);
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto m2 = a[ARG_BEHIND_MACRO];
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto m3 = OBJECT_BEHIND_MACRO[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-prefer-at-over-subscript-operator]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]

>From 659b87f223f21bacbcc7766292c054ca5edeb491 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Fri, 21 Jun 2024 10:44:39 +0200
Subject: [PATCH 19/28] Remove extra comment

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
index 33abbef5e8243..8fdfd5e9eb518 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
@@ -1,5 +1,4 @@
 //===--- ProBoundsAvoidUncheckedContainerAccesses.h - clang-tidy *- C++ -*-===//
-//===--- PreferMemberInitializerCheck.h - clang-tidy ------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.

>From da1cd78e4e5d2f501d67c2313d22f10423fc06f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Fri, 21 Jun 2024 10:52:42 +0200
Subject: [PATCH 20/28] Mention bounds safety profile explicitly

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../pro-bounds-avoid-unchecked-container-accesses.rst         | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
index 616882738653d..f39c5171110a0 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
@@ -35,4 +35,6 @@ Options
 
 This check enforces part of the `SL.con.3
 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>`
-guideline.
+guideline and is part of the `Bounds Safety (Bounds 4)
+<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Pro-bounds-arrayindex>` profile 
+profile from the C++ Core Guidelines.

>From 1188fb56d078bb9948d7d29814daea7c14433125 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Fri, 21 Jun 2024 10:55:53 +0200
Subject: [PATCH 21/28] Move paragraph about which rule/profile is being
 implemented above "Options"

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 ...pro-bounds-avoid-unchecked-container-accesses.rst | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
index f39c5171110a0..b62ec4fc7b6b5 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.rst
@@ -25,6 +25,12 @@ The classes ``std::map``, ``std::unordered_map`` and ``std::flat_map`` are
 excluded from this check, because for them the subscript operator has a defined
 behaviour when a key does not exist (inserting a new element).
 
+This check enforces part of the `SL.con.3
+<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>`
+guideline and is part of the `Bounds Safety (Bounds 4)
+<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Pro-bounds-arrayindex>` profile 
+profile from the C++ Core Guidelines.
+
 Options
 -------
 
@@ -32,9 +38,3 @@ Options
 
     Semicolon-delimited list of class names that should additionally be
     excluded from this check. By default empty.
-
-This check enforces part of the `SL.con.3
-<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#slcon3-avoid-bounds-errors>`
-guideline and is part of the `Bounds Safety (Bounds 4)
-<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Pro-bounds-arrayindex>` profile 
-profile from the C++ Core Guidelines.

>From 93a504adc278e01ed44698286ad275ed538d153a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Fri, 21 Jun 2024 11:09:05 +0200
Subject: [PATCH 22/28] Rename variables related to class exclusion mechanism

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 ...oBoundsAvoidUncheckedContainerAccesses.cpp | 26 ++++++++++---------
 ...ProBoundsAvoidUncheckedContainerAccesses.h |  2 +-
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 19a52d0e565fa..b68583a77ac7f 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -17,7 +17,7 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
-static constexpr std::array<llvm::StringRef, 3> DefaultExclusions = {
+static constexpr std::array<llvm::StringRef, 3> SubscriptDefaultExclusions = {
     llvm::StringRef("::std::map"), llvm::StringRef("::std::unordered_map"),
     llvm::StringRef("::std::flat_map")};
 
@@ -26,29 +26,30 @@ ProBoundsAvoidUncheckedContainerAccesses::
                                              ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context) {
 
-  ExcludedClasses = clang::tidy::utils::options::parseStringList(
+  SubscriptExcludedClasses = clang::tidy::utils::options::parseStringList(
       Options.get("ExcludeClasses", ""));
-  ExcludedClasses.insert(ExcludedClasses.end(), DefaultExclusions.begin(),
-                         DefaultExclusions.end());
+  SubscriptExcludedClasses.insert(SubscriptExcludedClasses.end(),
+                                  SubscriptDefaultExclusions.begin(),
+                                  SubscriptDefaultExclusions.end());
 }
 
 void ProBoundsAvoidUncheckedContainerAccesses::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
 
-  if (ExcludedClasses.size() == DefaultExclusions.size()) {
+  if (SubscriptExcludedClasses.size() == SubscriptDefaultExclusions.size()) {
     Options.store(Opts, "ExcludeClasses", "");
     return;
   }
 
   // Sum up the sizes of the defaults ( + semicolons), so we can remove them
   // from the saved options
-  size_t DefaultsStringLength =
-      std::transform_reduce(DefaultExclusions.begin(), DefaultExclusions.end(),
-                            DefaultExclusions.size(), std::plus<>(),
-                            [](llvm::StringRef Name) { return Name.size(); });
+  size_t DefaultsStringLength = std::transform_reduce(
+      SubscriptDefaultExclusions.begin(), SubscriptDefaultExclusions.end(),
+      SubscriptDefaultExclusions.size(), std::plus<>(),
+      [](llvm::StringRef Name) { return Name.size(); });
 
-  std::string Serialized =
-      clang::tidy::utils::options::serializeStringList(ExcludedClasses);
+  std::string Serialized = clang::tidy::utils::options::serializeStringList(
+      SubscriptExcludedClasses);
 
   Options.store(Opts, "ExcludeClasses",
                 Serialized.substr(0, Serialized.size() - DefaultsStringLength));
@@ -94,7 +95,8 @@ void ProBoundsAvoidUncheckedContainerAccesses::registerMatchers(
               cxxMethodDecl(hasOverloadedOperatorName("[]")).bind("operator")),
           callee(cxxMethodDecl(
               ofClass(cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")),
-              unless(matchers::matchesAnyListedName(ExcludedClasses)))))
+              unless(
+                  matchers::matchesAnyListedName(SubscriptExcludedClasses)))))
           .bind("caller"),
       this);
 }
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
index 8fdfd5e9eb518..3776869e6d42a 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.h
@@ -32,7 +32,7 @@ class ProBoundsAvoidUncheckedContainerAccesses : public ClangTidyCheck {
 
 private:
   // A list of class names that are excluded from the warning
-  std::vector<llvm::StringRef> ExcludedClasses;
+  std::vector<llvm::StringRef> SubscriptExcludedClasses;
 };
 
 } // namespace clang::tidy::cppcoreguidelines

>From 5969c6381f7fd624d33010e849d94f5b62ea0925 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 14:57:07 +0200
Subject: [PATCH 23/28] Remove redundant nullptr cast

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../ProBoundsAvoidUncheckedContainerAccesses.cpp                | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index b68583a77ac7f..560ccf3c7ca86 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -82,7 +82,7 @@ const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
 
     return Method;
   }
-  return static_cast<CXXMethodDecl *>(nullptr);
+  return nullptr;
 }
 
 void ProBoundsAvoidUncheckedContainerAccesses::registerMatchers(

>From 825c3acd5182d8d749a9654a25aab9e53601c78b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 15:04:00 +0200
Subject: [PATCH 24/28] Refactor the check's matcher as per 5chmidti's
 suggestion

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 ...oBoundsAvoidUncheckedContainerAccesses.cpp | 24 +++++++++----------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 560ccf3c7ca86..054aa852ca664 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -55,9 +55,9 @@ void ProBoundsAvoidUncheckedContainerAccesses::storeOptions(
                 Serialized.substr(0, Serialized.size() - DefaultsStringLength));
 }
 
-const CXXMethodDecl *findAlternative(const CXXRecordDecl *MatchedParent,
-                                     const CXXMethodDecl *MatchedOperator) {
-  for (const CXXMethodDecl *Method : MatchedParent->methods()) {
+const CXXMethodDecl *findAlternative(const CXXMethodDecl *MatchedOperator) {
+  const CXXRecordDecl *Parent = MatchedOperator->getParent();
+  for (const CXXMethodDecl *Method : Parent->methods()) {
     const bool CorrectName = Method->getNameInfo().getAsString() == "at";
     if (!CorrectName)
       continue;
@@ -90,13 +90,13 @@ void ProBoundsAvoidUncheckedContainerAccesses::registerMatchers(
   // Need a callExpr here to match CXXOperatorCallExpr ``(&a)->operator[](0)``
   // and CXXMemberCallExpr ``a[0]``.
   Finder->addMatcher(
-      callExpr(
-          callee(
-              cxxMethodDecl(hasOverloadedOperatorName("[]")).bind("operator")),
-          callee(cxxMethodDecl(
-              ofClass(cxxRecordDecl(hasMethod(hasName("at"))).bind("parent")),
-              unless(
-                  matchers::matchesAnyListedName(SubscriptExcludedClasses)))))
+      mapAnyOf(cxxOperatorCallExpr, cxxMemberCallExpr)
+          .with(callee(cxxMethodDecl(hasOverloadedOperatorName("[]"),
+                                     ofClass(cxxRecordDecl(hasMethod(
+                                         cxxMethodDecl(hasName("at"))))),
+                                     unless(matchers::matchesAnyListedName(
+                                         SubscriptExcludedClasses)))
+                           .bind("operator")))
           .bind("caller"),
       this);
 }
@@ -106,10 +106,8 @@ void ProBoundsAvoidUncheckedContainerAccesses::check(
   const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
   const auto *MatchedOperator =
       Result.Nodes.getNodeAs<CXXMethodDecl>("operator");
-  const auto *MatchedParent = Result.Nodes.getNodeAs<CXXRecordDecl>("parent");
 
-  const CXXMethodDecl *Alternative =
-      findAlternative(MatchedParent, MatchedOperator);
+  const CXXMethodDecl *Alternative = findAlternative(MatchedOperator);
   if (!Alternative)
     return;
 

>From 513207c80729625666798ec46b028649f5cb8e36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 15:15:10 +0200
Subject: [PATCH 25/28] Check that alternative is accessible in
 findAlternative() as per @5chmidti's and @PiotrZSL's suggestions

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../ProBoundsAvoidUncheckedContainerAccesses.cpp  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 054aa852ca664..d48b19bb36711 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -57,7 +57,22 @@ void ProBoundsAvoidUncheckedContainerAccesses::storeOptions(
 
 const CXXMethodDecl *findAlternative(const CXXMethodDecl *MatchedOperator) {
   const CXXRecordDecl *Parent = MatchedOperator->getParent();
+  const QualType SubscriptThisObjType =
+      MatchedOperator->getFunctionObjectParameterReferenceType();
+
   for (const CXXMethodDecl *Method : Parent->methods()) {
+    // Require 'Method' to be as accessible as 'MatchedOperator' or more
+    if (MatchedOperator->getAccess() < Method->getAccess())
+      continue;
+
+    if (MatchedOperator->isConst() != Method->isConst())
+      continue;
+
+    const QualType AtThisObjType =
+        Method->getFunctionObjectParameterReferenceType();
+    if (SubscriptThisObjType != AtThisObjType)
+      continue;
+
     const bool CorrectName = Method->getNameInfo().getAsString() == "at";
     if (!CorrectName)
       continue;

>From 75ea58c2e8df5384feeb912db0239702a564d087 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 15:28:10 +0200
Subject: [PATCH 26/28] Use upticks when diagnostic messages refer to code

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 ...oBoundsAvoidUncheckedContainerAccesses.cpp |  4 ++--
 ...nds-avoid-unchecked-container-accesses.cpp | 22 +++++++++----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index d48b19bb36711..8998cbfc1aeb2 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -127,9 +127,9 @@ void ProBoundsAvoidUncheckedContainerAccesses::check(
     return;
 
   diag(MatchedExpr->getBeginLoc(),
-       "found possibly unsafe operator[], consider using at() instead")
+       "found possibly unsafe 'operator[]', consider using 'at()' instead")
       << MatchedExpr->getSourceRange();
-  diag(Alternative->getBeginLoc(), "alternative at() defined here",
+  diag(Alternative->getBeginLoc(), "alternative 'at()' defined here",
        DiagnosticIDs::Note)
       << Alternative->getSourceRange();
 }
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
index 1a7a7fba7d8a2..9801dbb94ae27 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-avoid-unchecked-container-accesses.cpp
@@ -72,22 +72,22 @@ class ExcludedClass2 {
 std::array<int, 3> a;
 
 auto b = a[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto c = a[1+1];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 constexpr int Index = 1;
 auto d = a[Index];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 int e(int Ind) {
   return a[Ind];
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 }
 
 auto f = (&a)->operator[](1);
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto g = a.at(0);
 
@@ -102,16 +102,16 @@ auto m = n[0];
 
 SubClass Sub;
 auto r = Sub[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 typedef std::array<int, 3> ar;
 ar BehindDef;
 auto u = BehindDef[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 template<typename T> int TestTemplate(T t){
   return t[0];
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 }
 
@@ -133,10 +133,10 @@ auto y = TestMap[0];
 #define OBJECT_BEHIND_MACRO a
 
 auto m1 = SUBSCRIPT_BEHIND_MARCO(0);
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto m2 = a[ARG_BEHIND_MACRO];
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
 
 auto m3 = OBJECT_BEHIND_MACRO[0];
-// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe operator[], consider using at() instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: found possibly unsafe 'operator[]', consider using 'at()' instead [cppcoreguidelines-pro-bounds-avoid-unchecked-container-accesses]

>From a9d6c343f1a4c2188155046cd4b3375a931f7c18 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 15:31:24 +0200
Subject: [PATCH 27/28] Make findAlternative() static

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../ProBoundsAvoidUncheckedContainerAccesses.cpp               | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 8998cbfc1aeb2..324a36296aa77 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -55,7 +55,8 @@ void ProBoundsAvoidUncheckedContainerAccesses::storeOptions(
                 Serialized.substr(0, Serialized.size() - DefaultsStringLength));
 }
 
-const CXXMethodDecl *findAlternative(const CXXMethodDecl *MatchedOperator) {
+static const CXXMethodDecl *
+findAlternative(const CXXMethodDecl *MatchedOperator) {
   const CXXRecordDecl *Parent = MatchedOperator->getParent();
   const QualType SubscriptThisObjType =
       MatchedOperator->getFunctionObjectParameterReferenceType();

>From 08a60919f4ee7d3ab94e865385c6bcbd14ba7cce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger at tum.de>
Date: Sun, 30 Jun 2024 15:33:49 +0200
Subject: [PATCH 28/28] Move MatchedExpr definition closer to where it's first
 used in ProBoundsAvoidUncheckedContainerAccesses::check()

Co-authored-by: Manuel Pietsch <manuelpietsch at outlook.de>
---
 .../ProBoundsAvoidUncheckedContainerAccesses.cpp             | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
index 324a36296aa77..f3dff0769e994 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccesses.cpp
@@ -119,14 +119,15 @@ void ProBoundsAvoidUncheckedContainerAccesses::registerMatchers(
 
 void ProBoundsAvoidUncheckedContainerAccesses::check(
     const MatchFinder::MatchResult &Result) {
-  const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
   const auto *MatchedOperator =
       Result.Nodes.getNodeAs<CXXMethodDecl>("operator");
-
   const CXXMethodDecl *Alternative = findAlternative(MatchedOperator);
+
   if (!Alternative)
     return;
 
+  const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("caller");
+
   diag(MatchedExpr->getBeginLoc(),
        "found possibly unsafe 'operator[]', consider using 'at()' instead")
       << MatchedExpr->getSourceRange();