Fix #647 (Crash during tokenizing (wrong) K&R function declaration)

http://sourceforge.net/apps/trac/cppcheck/ticket/647
Thanks to undingen for providing a patch

src/tokenize.cpp

@@ -2279,6 +2279,14 @@ void Tokenizer::simplifyFunctionParameters()
                     break;
                 }
 
+                if (argumentNames.find(tok->str()) != argumentNames.end())
+                {
+                    // Invalid code, two arguments with the same name.
+                    // TODO, print error perhaps?
+                    bailOut = true;
+                    break;
+                }
+
                 argumentNames[tok->str()] = tok;
                 if (tok->next()->str() == ")")
                 {

test/testsimplifytokens.cpp

@@ -111,6 +111,9 @@ private:
 
         // Simplify nested strcat() calls
         TEST_CASE(strcat1);
+
+        // Syntax error
+        TEST_CASE(argumentsWithSameName)
     }
 
     std::string tok(const char code[])
@@ -1363,6 +1366,16 @@ private:
 
         ASSERT_EQUALS(expect, tok(code));
     }
+
+    void argumentsWithSameName()
+    {
+        // This code has syntax error, two variables can not have the same name
+        const char code[] = "void foo(x, x)\n"
+                            " int x;\n"
+                            " int x;\n"
+                            "{}\n";
+        ASSERT_EQUALS("void foo ( x , x ) int x ; int x ; { }", tok(code));
+    }
 };
 
 REGISTER_TEST(TestSimplifyTokens)