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[clang-tidy][modernize-use-starts-ends-with] Fix operator rewriting false negative #117837

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Merged
merged 1 commit into from
Nov 27, 2024
+23 −7
Merged

[clang-tidy][modernize-use-starts-ends-with] Fix operator rewriting false negative #117837

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10 changes: 7 additions & 3 deletions clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,12 +20,16 @@ using namespace clang::ast_matchers;
namespace clang::tidy::modernize {

static bool isNegativeComparison(const Expr *ComparisonExpr) {
if (const auto *BO = llvm::dyn_cast<BinaryOperator>(ComparisonExpr))
return BO->getOpcode() == BO_NE;
if (const auto *Op = llvm::dyn_cast<BinaryOperator>(ComparisonExpr))
return Op->getOpcode() == BO_NE;

if (const auto *Op = llvm::dyn_cast<CXXOperatorCallExpr>(ComparisonExpr))
return Op->getOperator() == OO_ExclaimEqual;

if (const auto *Op =
llvm::dyn_cast<CXXRewrittenBinaryOperator>(ComparisonExpr))
return Op->getOperator() == BO_NE;

return false;
}

Expand Down Expand Up @@ -185,7 +189,7 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {

// Case 6: X.substr(0, LEN(Y)) [!=]= Y -> starts_with.
Finder->addMatcher(
cxxOperatorCallExpr(
binaryOperation(
hasAnyOperatorName("==", "!="),
hasOperands(
expr().bind("needle"),
Expand Down
10 changes: 6 additions & 4 deletions clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string
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Expand Up @@ -136,10 +136,6 @@ bool operator==(const std::string&, const std::string&);
bool operator==(const std::string&, const char*);
bool operator==(const char*, const std::string&);

bool operator!=(const std::string&, const std::string&);
bool operator!=(const std::string&, const char*);
bool operator!=(const char*, const std::string&);

bool operator==(const std::wstring&, const std::wstring&);
bool operator==(const std::wstring&, const wchar_t*);
bool operator==(const wchar_t*, const std::wstring&);
Expand All @@ -148,9 +144,15 @@ bool operator==(const std::string_view&, const std::string_view&);
bool operator==(const std::string_view&, const char*);
bool operator==(const char*, const std::string_view&);

#if __cplusplus < 202002L
bool operator!=(const std::string&, const std::string&);
bool operator!=(const std::string&, const char*);
bool operator!=(const char*, const std::string&);

bool operator!=(const std::string_view&, const std::string_view&);
bool operator!=(const std::string_view&, const char*);
bool operator!=(const char*, const std::string_view&);
#endif

size_t strlen(const char* str);
}
Expand Down
10 changes: 10 additions & 0 deletions clang-tools-extra/test/clang-tidy/checkers/modernize/use-starts-ends-with.cpp
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Expand Up @@ -320,3 +320,13 @@ void test_substr() {

str.substr(0, strlen("hello123")) == "hello";
}

void test_operator_rewriting(std::string str, std::string prefix) {
str.substr(0, prefix.size()) == prefix;
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of substr
// CHECK-FIXES: str.starts_with(prefix);

str.substr(0, prefix.size()) != prefix;
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of substr
// CHECK-FIXES: !str.starts_with(prefix);
}