Fixed #5168 (segmentation fault (invalid code) in Tokenizer::simplifyVarDecl)

lib/tokenize.cpp

@@ -3175,7 +3175,7 @@ void Tokenizer::createLinks2()
         if (token->link()) {
             if (Token::Match(token, "{|[|("))
                 type.push(token);
-            else if (Token::Match(token, "}|]|)")) {
+            else if (!type.empty() && Token::Match(token, "}|]|)")) {
                 while (type.top()->str() == "<")
                     type.pop();
                 type.pop();

test/testsimplifytokens.cpp

@@ -134,6 +134,7 @@ private:
         TEST_CASE(template39);  // #4742 - freeze
         TEST_CASE(template40);  // #5055 - template specialization outside struct
         TEST_CASE(template41);  // #4710 - const in instantiation not handled perfectly
+        TEST_CASE(template42);  // #4878 - variadic templates
         TEST_CASE(template_unhandled);
         TEST_CASE(template_default_parameter);
         TEST_CASE(template_default_type);
@@ -2350,6 +2351,19 @@ private:
         ASSERT_EQUALS("int x ( ) { return f<int> ( 123 ) ; } int f<int> ( int t ) { return t ; }", tok(code2));
     }
 
+    void template42() { // #4878 cpcheck aborts in ext-blocks.cpp (clang testcode)
+        const char code[] = "template<typename ...Args>\n"
+                            "int f0(Args ...args) {\n"
+                            "  return ^ {\n"
+                            "    return sizeof...(Args);\n"
+                            "  }() + ^ {\n"
+                            "    return sizeof...(args);\n"
+                            "  }();\n"
+                            "}";
+        tok(code);
+    }
+
+
     void template_default_parameter() {
         {
             const char code[] = "template <class T, int n=3>\n"