[clang-tidy] Fix FP with readability-redundant-string-init for defaul…

…t arguments Summary: Clang-tidy is reporting a warning of redundant string initialisation on a string parameter initialized with empty string. See bug: 27087 The reported example is: ``` #include <string> void fn(std::string a = ""); ``` Reviewers: alexfh Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D18829 llvm-svn: 265671
llvm · Apr 7, 2016 · f6660da · f6660da
1 parent e23b6de
commit f6660da
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/clang-tools-extra/clang-tidy/readability/RedundantStringInitCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantStringInitCheck.cpp
@@ -61,7 +61,8 @@ void RedundantStringInitCheck::registerMatchers(MatchFinder *Finder) {
                         hasInitializer(
                             expr(anyOf(EmptyStringCtorExpr,
                                        EmptyStringCtorExprWithTemporaries))
-                            .bind("expr"))))
+                            .bind("expr"))),
+                unless(parmVarDecl()))
           .bind("decl"),
       this);
 }

diff --git a/clang-tools-extra/test/clang-tidy/readability-redundant-string-init.cpp b/clang-tools-extra/test/clang-tidy/readability-redundant-string-init.cpp
@@ -131,3 +131,10 @@ void k() {
 
   std::string d = "u", e = "u", f = "u";
 }
+
+// These cases should not generate warnings.
+extern void Param1(std::string param = "");
+extern void Param2(const std::string& param = "");
+void Param3(std::string param = "") {}
+void Param4(STRING param = "") {}
+