[clang-tidy] exclude CXXParenListInitExpr from RedundantCastingCheck (#109741)

Exclude CXXParenListInitExpr from RedundantCastingCheck because there
are false positive cases. Currently, we can't think of positive cases
for CXXParenListInitExpr. This can be improved by following the
initListExpr method if we can come up with some positive cases.

Fixes #108846

Author: dl8sd11

clang-tools-extra/clang-tidy/readability/RedundantCastingCheck.cpp

@@ -108,6 +108,10 @@ void RedundantCastingCheck::registerMatchers(MatchFinder *Finder) {
 
   auto BitfieldMemberExpr = memberExpr(member(fieldDecl(isBitField())));
 
+  const ast_matchers::internal::VariadicDynCastAllOfMatcher<
+      Stmt, CXXParenListInitExpr>
+      cxxParenListInitExpr; // NOLINT(readability-identifier-naming)
+
   Finder->addMatcher(
       explicitCastExpr(
           unless(hasCastKind(CK_ConstructorConversion)),
@@ -117,6 +121,7 @@ void RedundantCastingCheck::registerMatchers(MatchFinder *Finder) {
           hasDestinationType(qualType().bind("dstType")),
           hasSourceExpression(anyOf(
               expr(unless(initListExpr()), unless(BitfieldMemberExpr),
+                   unless(cxxParenListInitExpr()),
                    hasType(qualType().bind("srcType")))
                   .bind("source"),
               initListExpr(unless(hasInit(1, expr())),

clang-tools-extra/docs/ReleaseNotes.rst

@@ -360,6 +360,11 @@ Changes in existing checks
   case of the literal suffix in fixes and fixing false positive for implicit
   conversion of comparison result in C23.
 
+- Improved :doc:`readability-redundant-casting
+  <clang-tidy/checks/readability/redundant-casting>` check
+  by addressing a false positive in aggregate initialization through
+  parenthesized list.
+
 - Improved :doc:`readability-redundant-smartptr-get
   <clang-tidy/checks/readability/redundant-smartptr-get>` check to
   remove `->`, when redundant `get()` is removed.

clang-tools-extra/test/clang-tidy/checkers/readability/redundant-casting.cpp

@@ -1,10 +1,18 @@
-// RUN: %check_clang_tidy -std=c++11-or-later %s readability-redundant-casting %t -- -- -fno-delayed-template-parsing
-// RUN: %check_clang_tidy -std=c++11-or-later -check-suffix=,MACROS %s readability-redundant-casting %t -- \
+// RUN: %check_clang_tidy -std=c++11,c++14,c++17 %s readability-redundant-casting %t -- -- -fno-delayed-template-parsing
+// RUN: %check_clang_tidy -std=c++11,c++14,c++17 -check-suffix=,MACROS %s readability-redundant-casting %t -- \
 // RUN:   -config='{CheckOptions: { readability-redundant-casting.IgnoreMacros: false }}' \
 // RUN:   -- -fno-delayed-template-parsing
-// RUN: %check_clang_tidy -std=c++11-or-later -check-suffix=,ALIASES %s readability-redundant-casting %t -- \
+// RUN: %check_clang_tidy -std=c++11,c++14,c++17 -check-suffix=,ALIASES %s readability-redundant-casting %t -- \
 // RUN:   -config='{CheckOptions: { readability-redundant-casting.IgnoreTypeAliases: true }}' \
 // RUN:   -- -fno-delayed-template-parsing
+// RUN: %check_clang_tidy -std=c++20 %s readability-redundant-casting %t -- \
+// RUN:   -- -fno-delayed-template-parsing -D CXX_20=1
+// RUN: %check_clang_tidy -std=c++20 -check-suffix=,MACROS %s readability-redundant-casting %t -- \
+// RUN:   -config='{CheckOptions: { readability-redundant-casting.IgnoreMacros: false }}' \
+// RUN:   -- -fno-delayed-template-parsing -D CXX_20=1
+// RUN: %check_clang_tidy -std=c++20 -check-suffix=,ALIASES %s readability-redundant-casting %t -- \
+// RUN:   -config='{CheckOptions: { readability-redundant-casting.IgnoreTypeAliases: true }}' \
+// RUN:   -- -fno-delayed-template-parsing -D CXX_20=1
 
 struct A {};
 struct B : A {};
@@ -57,6 +65,12 @@ void testDiffrentTypesCast(B& value) {
   A& a7 = static_cast<A&>(value);
 }
 
+#ifdef CXX_20
+void testParenListInitExpr(A value) {
+  B b = static_cast<B>(value);
+}
+#endif
+
 void testCastingWithAuto() {
   auto a = getA();
   A& a8 = static_cast<A&>(a);