https://github.com/gxyd created https://github.com/llvm/llvm-project/pull/191386
Mark explicit casting as readabily redundant for a BinaryOperation with atleast one operand of the same type as the cast type in `RedundantCastingCheck` E.g.; `static<float>(1 + 2.0f)` // redundant cast Fixes #182132 >From 7d7cfaec6c4fa6897baa8e7f32a78dc33910fc6b Mon Sep 17 00:00:00 2001 From: Gaurav Dhingra <[email protected]> Date: Fri, 10 Apr 2026 16:14:58 +0530 Subject: [PATCH] [clang-tidy] Improve redundant-casting check for binary operation Mark explicit casting as readabily redundant for a BinaryOperation with atleast one operand of the same type as the cast type in `RedundantCastingCheck` E.g.; `static<float>(1 + 2.0f)` // redundant cast Fixes #182132 --- .../readability/RedundantCastingCheck.cpp | 17 ++++++++++------- .../checkers/readability/redundant-casting.cpp | 16 ++++++++++++++++ 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/clang-tools-extra/clang-tidy/readability/RedundantCastingCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantCastingCheck.cpp index eae0b3f6d0e7d..9dc4cef139125 100644 --- a/clang-tools-extra/clang-tidy/readability/RedundantCastingCheck.cpp +++ b/clang-tools-extra/clang-tidy/readability/RedundantCastingCheck.cpp @@ -50,7 +50,7 @@ static bool areTypesEqual(QualType TypeS, QualType TypeD, TypeD.getLocalUnqualifiedType()); } -static bool areBinaryOperatorOperandsTypesEqualToOperatorResultType( +static bool anyBinaryOperatorOperandsTypesEqualToOperatorResultType( const Expr *E, bool IgnoreTypeAliases) { if (!E) return true; @@ -64,12 +64,15 @@ static bool areBinaryOperatorOperandsTypesEqualToOperatorResultType( const QualType NonReferenceType = Type.getNonReferenceType(); const QualType LHSType = B->getLHS()->IgnoreImplicit()->getType(); - if (LHSType.isNull() || !areTypesEqual(LHSType.getNonReferenceType(), - NonReferenceType, IgnoreTypeAliases)) - return false; const QualType RHSType = B->getRHS()->IgnoreImplicit()->getType(); - if (RHSType.isNull() || !areTypesEqual(RHSType.getNonReferenceType(), - NonReferenceType, IgnoreTypeAliases)) + const bool LHSMatches = + !LHSType.isNull() && areTypesEqual(LHSType.getNonReferenceType(), + NonReferenceType, IgnoreTypeAliases); + const bool RHSMatches = + !RHSType.isNull() && areTypesEqual(RHSType.getNonReferenceType(), + NonReferenceType, IgnoreTypeAliases); + if (!LHSMatches && !RHSMatches) + // neither of the operand matches => casting is needed for readability return false; } return true; @@ -145,7 +148,7 @@ void RedundantCastingCheck::check(const MatchFinder::MatchResult &Result) { if (!areTypesEqual(TypeS, TypeD, IgnoreTypeAliases)) return; - if (!areBinaryOperatorOperandsTypesEqualToOperatorResultType( + if (!anyBinaryOperatorOperandsTypesEqualToOperatorResultType( SourceExpr, IgnoreTypeAliases)) return; diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-casting.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-casting.cpp index 001057aeaa495..8a0f271d55e29 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-casting.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-casting.cpp @@ -14,6 +14,8 @@ // RUN: -config='{CheckOptions: { readability-redundant-casting.IgnoreTypeAliases: true }}' \ // RUN: -- -fno-delayed-template-parsing -D CXX_20=1 +#include <cstdint> + struct A {}; struct B : A {}; A getA(); @@ -168,6 +170,20 @@ void testFunctionalCastWithInitExpr(unsigned a) { unsigned c = unsigned{0}; } +void testBinaryOperatorRedundantCasting() { + const auto diff_types_operands1 { static_cast<float>(1.0f + 1) }; + // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting] + // CHECK-FIXES: const auto diff_types_operands1 { (1.0f + 1) }; + + const auto diff_types_operands2 { static_cast<float>(2 + 3.0f) }; + // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting] + // CHECK-FIXES: const auto diff_types_operands2 { (2 + 3.0f) }; + + const auto diff_types_operands3 { static_cast<int>(1 + static_cast<uint8_t>(1)) }; + // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: redundant explicit casting to the same type 'int' as the sub-expression, remove this casting [readability-redundant-casting] + // CHECK-FIXES: const auto diff_types_operands3 { (1 + static_cast<uint8_t>(1)) }; +} + void testBinaryOperator(char c) { int a = int(c - 'C'); } _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
