[clang-tools-extra] [clang-tidy]fix readability-implicit-bool-conversion false-positives when comparison bool bitfield (PR #77878)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-tidy

Author: Congcong Cai (HerrCai0907)

<details>
<summary>Changes</summary>

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 when add matcher

---
Full diff: https://github.com/llvm/llvm-project/pull/77878.diff


3 Files Affected:

- (modified) clang-tools-extra/clang-tidy/readability/ImplicitBoolConversionCheck.cpp (+2-3) 
- (modified) clang-tools-extra/docs/ReleaseNotes.rst (+2-1) 
- (modified) clang-tools-extra/test/clang-tidy/checkers/readability/implicit-bool-conversion-allow-in-conditions.cpp (+3) 


``````````diff
diff --git a/clang-tools-extra/clang-tidy/readability/ImplicitBoolConversionCheck.cpp b/clang-tools-extra/clang-tidy/readability/ImplicitBoolConversionCheck.cpp
index f0fca30de3b3c4..672f28721114c9 100644
--- a/clang-tools-extra/clang-tidy/readability/ImplicitBoolConversionCheck.cpp
+++ b/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
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index b4d87e0ed2a67a..f7274229bf52ce 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -478,7 +478,8 @@ 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
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/implicit-bool-conversion-allow-in-conditions.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/implicit-bool-conversion-allow-in-conditions.cpp
index e393e297140cbd..48984d29322872 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/implicit-bool-conversion-allow-in-conditions.cpp
+++ b/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()) {}

``````````

</details>


https://github.com/llvm/llvm-project/pull/77878