[clang-tidy]`pro-bounds-array-to-pointer-decay` ignore predefined expression

[HerrCai0907]

Summary

cast PredefinedExpr such as __func__ to const char* should be accpetted.

[Eugene.Zelenko]

clang-tools-extra/docs/ReleaseNotes.rst

191

Please enclose __func__ in double back-ticks.

[HerrCai0907]

update release-note

[PiotrZSL]

LGTM

clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp

 //===--- ProBoundsArrayToPointerDecayCheck.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 "ProBoundsArrayToPointerDecayCheck.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ParentMapContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
 
 using namespace clang::ast_matchers;
 
 namespace clang::tidy::cppcoreguidelines {
 
 namespace {
 AST_MATCHER_P(CXXForRangeStmt, hasRangeBeginEndStmt,
               ast_matchers::internal::Matcher<DeclStmt>, InnerMatcher) {
void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
   // 1) just before array subscription
   // 2) inside a range-for over an array
   // 3) if it converts a string literal to a pointer
   Finder->addMatcher(
       traverse(
           TK_AsIs,
           implicitCastExpr(
               unless(hasParent(arraySubscriptExpr())),
+              unless(hasSourceExpression(predefinedExpr())),
               unless(hasParentIgnoringImpCasts(explicitCastExpr())),
               unless(isInsideOfRangeBeginEndStmt()),
               unless(hasSourceExpression(ignoringParens(stringLiteral()))),
               unless(hasSourceExpression(ignoringParens(
                   conditionalOperator(hasTrueExpression(stringLiteral()),
                                       hasFalseExpression(stringLiteral()))))))
               .bind("cast")),
       this);

clang-tools-extra/docs/ReleaseNotes.rst

- Improved :doc:`cppcoreguidelines-avoid-non-const-global-variables
   <clang-tidy/checks/cppcoreguidelines/avoid-non-const-global-variables>` check
   to ignore ``static`` variables declared within the scope of
   ``class``/``struct``.
 
 - Improved :doc:`cppcoreguidelines-prefer-member-initializer
   <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer>` check to
   ignore delegate constructors.
 
+- Improved :doc `cppcoreguidelines-pro-bounds-array-to-pointer-decay
+  <clang-tidy/checks/cppcoreguidelines/pro-bounds-array-to-pointer-decay>` check 
+  to ignore predefined expression (e.g., ``__func__``, ...).
+
 - Improved :doc:`cppcoreguidelines-pro-type-member-init
   <clang-tidy/checks/cppcoreguidelines/pro-type-member-init>` check to ignore
   dependent delegate constructors.
 
 - Improved :doc:`cppcoreguidelines-pro-type-vararg
   <clang-tidy/checks/cppcoreguidelines/pro-type-vararg>` check to ignore
   false-positives in unevaluated context (e.g., ``decltype``, ``sizeof``, ...).
 

clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-array-to-pointer-decay.cpp

 }
 
 const char *g() {
   return "clang"; // OK, decay string literal to pointer
 }
 const char *g2() {
     return ("clang"); // OK, ParenExpr hides the literal-pointer decay
 }
+const char *g3() {
+    return __func__; // OK, don't diagnose PredefinedExpr
+}
 
 void f2(void *const *);
 void bug25362() {
   void *a[2];
   f2(static_cast<void *const*>(a)); // OK, explicit cast
 }
 
 void issue31155(int i) {