feedback

Author: hjanuschka

clang-tools-extra/clang-tidy/modernize/UseStartsEndsWithCheck.cpp

@@ -183,7 +183,7 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
           .bind("expr"),
       this);
 
-  // Case 6: X.substr(0, LEN(Y)) [!=]= Y -> ends_with.
+  // Case 6: X.substr(0, LEN(Y)) [!=]= Y -> starts_with.
   Finder->addMatcher(
       cxxOperatorCallExpr(
           hasAnyOperatorName("==", "!="),
@@ -218,6 +218,9 @@ void UseStartsEndsWithCheck::check(const MatchFinder::MatchResult &Result) {
       FindExpr->getBeginLoc().isMacroID())
     return;
 
+  if (FindExpr->getNumArgs() == 0)
+    return;
+
   const bool Neg = isNegativeComparison(ComparisonExpr);
 
   // Retrieve the source text of the search expression.
@@ -240,9 +243,6 @@ void UseStartsEndsWithCheck::check(const MatchFinder::MatchResult &Result) {
                                        ReplacementFunction->getName());
 
   // Replace arguments and everything after the function call.
-  if (FindExpr->getNumArgs() == 0) {
-    return;
-  }
   Diag << FixItHint::CreateReplacement(
       CharSourceRange::getTokenRange(FindExpr->getArg(0)->getBeginLoc(),
                                      ComparisonExpr->getEndLoc()),

clang-tools-extra/test/clang-tidy/checkers/modernize/use-starts-ends-with.cpp

@@ -303,6 +303,11 @@ void test_substr() {
     // CHECK-FIXES: str.starts_with(prefix);
 
     // Tests to verify macro behavior
+    #define MSG "hello"
+    str.substr(0, strlen(MSG)) == MSG;
+    // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of substr() == [modernize-use-starts-ends-with]
+    // CHECK-FIXES: str.starts_with(MSG);
+
     #define STARTS_WITH(X, Y) (X).substr(0, (Y).size()) == (Y)
     STARTS_WITH(str, prefix);