[clang-tidy]fix readability-implicit-bool-conversion false-positives …

…when comparison bool bitfield (#77878)

Fixes: #76817
For ignoring comparison and xor operator, it needs
to use `ImplicitCastFromBool` without ignoring
exception cases.
This patch splits ignoring exception cases logic
from `ImplicitCastFromBool` and only applies
it during matching targeted AST.

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

@@ -274,8 +274,7 @@ void ImplicitBoolConversionCheck::registerMatchers(MatchFinder *Finder) {
             allOf(anyOf(hasCastKind(CK_NullToPointer),
                         hasCastKind(CK_NullToMemberPointer)),
                   hasSourceExpression(cxxBoolLiteral()))),
-      hasSourceExpression(expr(hasType(booleanType()))),
-      unless(ExceptionCases));
+      hasSourceExpression(expr(hasType(booleanType()))));
   auto BoolXor =
       binaryOperator(hasOperatorName("^"), hasLHS(ImplicitCastFromBool),
                      hasRHS(ImplicitCastFromBool));
@@ -315,7 +314,7 @@ void ImplicitBoolConversionCheck::registerMatchers(MatchFinder *Finder) {
       traverse(
           TK_AsIs,
           implicitCastExpr(
-              ImplicitCastFromBool,
+              ImplicitCastFromBool, unless(ExceptionCases),
               // Exclude comparisons of bools, as they are always cast to
               // integers in such context:
               //   bool_expr_a == bool_expr_b

clang-tools-extra/docs/ReleaseNotes.rst

@@ -493,7 +493,8 @@ Changes in existing checks
   <clang-tidy/checks/readability/implicit-bool-conversion>` check to take
   do-while loops into account for the `AllowIntegerConditions` and
   `AllowPointerConditions` options. It also now provides more consistent
-  suggestions when parentheses are added to the return value.
+  suggestions when parentheses are added to the return value. It also ignores
+  false-positives for comparison containing bool bitfield.
 
 - Improved :doc:`readability-misleading-indentation
   <clang-tidy/checks/readability/misleading-indentation>` check to ignore

clang-tools-extra/test/clang-tidy/checkers/readability/implicit-bool-conversion-allow-in-conditions.cpp

@@ -12,6 +12,7 @@ int* functionReturningPointer();
 struct Struct {
   int member;
   unsigned bitfield : 1;
+  bool boolfield : 1;
 };
 
 
@@ -28,6 +29,8 @@ void implicitConversionIntegerToBoolInConditionalsIsAllowed() {
   if (!s.member) {}
   if (s.bitfield) {}
   if (!s.bitfield) {}
+  if (s.boolfield == true) {}
+  if (s.boolfield != true) {}
   if (functionReturningInt()) {}
   if (!functionReturningInt()) {}
   if (functionReturningInt() && functionReturningPointer()) {}