From ba3833c692eb408369e20d20b010405b39b45c41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Thu, 29 Nov 2012 07:10:56 +0100
Subject: [PATCH] Fixed #3678 (stlcstrReturn for classes which don't provide a
 std::string)

---
 lib/checkstl.cpp | 15 ++++++++++++---
 test/teststl.cpp |  6 ++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index ccab39baa..ffca82622 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -1196,7 +1196,7 @@ void CheckStl::string_c_str()
                         tok2 = tok2->previous();
                     if (tok2 && Token::simpleMatch(tok2->tokAt(-4), ". c_str ( )")) {
                         const Variable* var = symbolDatabase->getVariableFromVarId(tok2->tokAt(-5)->varId());
-                        if (var && Token::Match(var->typeStartToken(), "const| std :: string|wstring"))
+                        if (var && Token::Match(var->typeStartToken(), "const| std ::"))
                             string_c_strParam(tok, i->second);
                     }
                 }
@@ -1238,8 +1238,17 @@ void CheckStl::string_c_str()
             else if ((returnType == stdString || returnType == stdStringConstRef) && _settings->isEnabled("performance")) {
                 if (tok->str() == "return") {
                     const Token* tok2 = Token::findsimplematch(tok->next(), ";");
-                    if (Token::simpleMatch(tok2->tokAt(-4), ". c_str ( )"))
-                        string_c_strReturn(tok);
+                    if (Token::simpleMatch(tok2->tokAt(-4), ". c_str ( )")) {
+                        tok2 = tok2->tokAt(-5);
+                        if (tok2->isName()) {  // return var.c_str(); => check if var is a std type
+                            const Variable* var = symbolDatabase->getVariableFromVarId(tok2->varId());
+                            if (var && Token::Match(var->typeStartToken(), "const| std ::"))
+                                string_c_strReturn(tok);
+                        } else {
+                            // TODO: determine if a error should be written or not
+                            string_c_strReturn(tok);
+                        }
+                    }
                 }
             }
         }
diff --git a/test/teststl.cpp b/test/teststl.cpp
index 3d45eb4cc..0c2f7510b 100644
--- a/test/teststl.cpp
+++ b/test/teststl.cpp
@@ -1769,6 +1769,12 @@ private:
               "}");
         ASSERT_EQUALS("", errout.str());
 
+        check("std::string get_msg() {\n" // #3678
+              "    MyStringClass errmsg;\n"
+              "    return errmsg.c_str();\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
 
         check("void Foo1(const std::string& str) {}\n"
               "void Foo2(char* c, const std::string str) {}\n"