Author: v1nh1shungry Date: 2025-08-17T11:42:38+02:00 New Revision: 326d749a368a842e71fd0d4cd7bb97c6d9f52f3e
URL: https://github.com/llvm/llvm-project/commit/326d749a368a842e71fd0d4cd7bb97c6d9f52f3e DIFF: https://github.com/llvm/llvm-project/commit/326d749a368a842e71fd0d4cd7bb97c6d9f52f3e.diff LOG: [clang-tidy] Fix `cppcoreguidelines-prefer-member-initializer` false positive for inherited members (#153941) ```cpp struct Base { int m; }; template <class T> struct Derived : Base { Derived() { m = 0; } }; ``` would previously generate the following output: ``` <source>:7:15: warning: 'm' should be initialized in a member initializer of the constructor [cppcoreguidelines-prefer-member-initializer] 7 | Derived() { m = 0; } | ^~~~~~ | : m(0) ``` This patch fixes this false positive. Note that before this patch the checker won't give false positive for ```cpp struct Derived : Base { Derived() { m = 0; } }; ``` and the constructor's AST is ``` `-CXXConstructorDecl 0x557df03d1fb0 <line:7:3, col:22> col:3 Derived 'void ()' implicit-inline |-CXXCtorInitializer 'Base' | `-CXXConstructExpr 0x557df03d2748 <col:3> 'Base' 'void () noexcept' `-CompoundStmt 0x557df03d2898 <col:13, col:22> `-BinaryOperator 0x557df03d2878 <col:15, col:19> 'int' lvalue '=' |-MemberExpr 0x557df03d2828 <col:15> 'int' lvalue ->m 0x557df03d1c40 | `-ImplicitCastExpr 0x557df03d2808 <col:15> 'Base *' <UncheckedDerivedToBase (Base)> | `-CXXThisExpr 0x557df03d27f8 <col:15> 'Derived *' implicit this `-IntegerLiteral 0x557df03d2858 <col:19> 'int' 0 ``` so `isAssignmentToMemberOf` would return empty due to https://github.com/llvm/llvm-project/blob/f0967fca04c880e9aabd5be043a85127faabb4c6/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp#L118-L119 Fixes #104400 Added: Modified: clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp clang-tools-extra/docs/ReleaseNotes.rst clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp Removed: ################################################################################ diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp index 593a4f85d1309..79cd4bbcc9a60 100644 --- a/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp +++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp @@ -191,6 +191,9 @@ void PreferMemberInitializerCheck::check( if (!AssignmentToMember) continue; const FieldDecl *Field = AssignmentToMember->Field; + // Skip if the field is inherited from a base class. + if (Field->getParent() != Class) + continue; const Expr *InitValue = AssignmentToMember->Init; updateAssignmentLevel(Field, InitValue, Ctor, AssignedFields); if (!canAdvanceAssignment(AssignedFields[Field])) diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 36703dd32c03c..fd81b0d47e82b 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -167,6 +167,10 @@ Changes in existing checks an additional matcher that generalizes the copy-and-swap idiom pattern detection. +- Improved :doc:`cppcoreguidelines-prefer-member-initializer + <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer>` check to + avoid false positives on inherited members in class templates. + - Improved :doc:`misc-header-include-cycle <clang-tidy/checks/misc/header-include-cycle>` check performance. diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp index 7d6164946fc3d..e8d7db17f3c60 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp @@ -650,3 +650,16 @@ struct InitFromBindingDecl { } }; } // namespace GH82970 + +struct A { + int m; +}; + +struct B : A { + B() { m = 0; } +}; + +template <class T> +struct C : A { + C() { m = 0; } +}; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
