Author: Clement Courbet Date: 2021-10-29T08:41:03+02:00 New Revision: fc1b24d7360f59c8b89f1b6290fe849a6207dc44
URL: https://github.com/llvm/llvm-project/commit/fc1b24d7360f59c8b89f1b6290fe849a6207dc44 DIFF: https://github.com/llvm/llvm-project/commit/fc1b24d7360f59c8b89f1b6290fe849a6207dc44.diff LOG: [clang-tidy]performance-unnecessary-copy-initialization: fix false negative We're missing all cases where the return value is a type alias. Unfortunately, this includes things we care about, such as `std::vector<T>::operator[]` (return value is `const_reference`, not `const T&`). Match the canonical type instead. Differential Revision: https://reviews.llvm.org/D112722 Added: Modified: clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp clang-tools-extra/test/clang-tidy/checkers/performance-unnecessary-copy-initialization.cpp Removed: ################################################################################ diff --git a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp index 6f9495fd1e66c..2cdd7827ee42a 100644 --- a/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp +++ b/clang-tools-extra/clang-tidy/performance/UnnecessaryCopyInitialization.cpp @@ -84,7 +84,8 @@ AST_MATCHER_FUNCTION_P(StatementMatcher, isConstRefReturningMethodCall, // returned either points to a global static variable or to a member of the // called object. return cxxMemberCallExpr( - callee(cxxMethodDecl(returns(matchers::isReferenceToConst())) + callee(cxxMethodDecl( + returns(hasCanonicalType(matchers::isReferenceToConst()))) .bind(MethodDeclId)), on(declRefExpr(to( varDecl( @@ -97,7 +98,8 @@ AST_MATCHER_FUNCTION(StatementMatcher, isConstRefReturningFunctionCall) { // Only allow initialization of a const reference from a free function if it // has no arguments. Otherwise it could return an alias to one of its // arguments and the arguments need to be checked for const use as well. - return callExpr(callee(functionDecl(returns(matchers::isReferenceToConst())) + return callExpr(callee(functionDecl(returns(hasCanonicalType( + matchers::isReferenceToConst()))) .bind(FunctionDeclId)), argumentCountIs(0), unless(callee(cxxMethodDecl()))) .bind(InitFunctionCallId); diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance-unnecessary-copy-initialization.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance-unnecessary-copy-initialization.cpp index 68a010c4d953c..4c469c966860b 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/performance-unnecessary-copy-initialization.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/performance-unnecessary-copy-initialization.cpp @@ -12,6 +12,8 @@ struct ExpensiveToCopyType { ExpensiveToCopyType(); virtual ~ExpensiveToCopyType(); const ExpensiveToCopyType &reference() const; + using ConstRef = const ExpensiveToCopyType &; + ConstRef referenceWithAlias() const; const ExpensiveToCopyType *pointer() const; Iterator<ExpensiveToCopyType> begin() const; Iterator<ExpensiveToCopyType> end() const; @@ -206,6 +208,15 @@ void positiveNonConstVarInCodeBlock(const ExpensiveToCopyType &Obj) { } } +void positiveNonConstVarInCodeBlockWithAlias(const ExpensiveToCopyType &Obj) { + { + const ExpensiveToCopyType Assigned = Obj.referenceWithAlias(); + // CHECK-MESSAGES: [[@LINE-1]]:31: warning: the const qualified variable + // CHECK-FIXES: const ExpensiveToCopyType& Assigned = Obj.referenceWithAlias(); + useAsConstReference(Assigned); + } +} + void negativeNonConstVarWithNonConstUse(const ExpensiveToCopyType &Obj) { { auto NonConstInvoked = Obj.reference(); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
