[clang-tidy]pro-bounds-array-to-pointer-decay ignore predefined exp…

…ression

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

Reviewed By: PiotrZSL

Differential Revision: https://reviews.llvm.org/D158244

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

@@ -10,6 +10,7 @@
 #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;
 
@@ -56,6 +57,7 @@ void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
           TK_AsIs,
           implicitCastExpr(
               unless(hasParent(arraySubscriptExpr())),
+              unless(hasSourceExpression(predefinedExpr())),
               unless(hasParentIgnoringImpCasts(explicitCastExpr())),
               unless(isInsideOfRangeBeginEndStmt()),
               unless(hasSourceExpression(ignoringParens(stringLiteral()))),

clang-tools-extra/docs/ReleaseNotes.rst

@@ -186,6 +186,10 @@ Changes in existing checks
   <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.

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

@@ -43,6 +43,9 @@ const char *g() {
 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() {