Fix #6718 and #6719 (crashes on garbage code).

Local fixes avoiding access to NULL-token.  Also minor correction to
TemplateSimplifier::hasComplicatedSyntaxErrorsInTemplates()

lib/checkclass.cpp

@@ -819,7 +819,7 @@ void CheckClass::initializationListUsage()
                 const Variable* var = tok->variable();
                 if (var && var->scope() == owner && !var->isStatic()) {
                     bool allowed = true;
-                    for (const Token* tok2 = tok->tokAt(2); tok2->str() != ";"; tok2 = tok2->next()) {
+                    for (const Token* tok2 = tok->tokAt(2); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
                         if (tok2->varId()) {
                             const Variable* var2 = tok2->variable();
                             if (var2 && var2->scope() == owner &&

lib/templatesimplifier.cpp

@@ -128,7 +128,6 @@ bool TemplateSimplifier::hasComplicatedSyntaxErrorsInTemplates(const Token *toke
             tok = tok->link();
             if (!tok)
                 return true;
-
         }
         // skip executing scopes..
         const Token *start = Tokenizer::startOfExecutableScope(tok);
@@ -212,8 +211,8 @@ bool TemplateSimplifier::hasComplicatedSyntaxErrorsInTemplates(const Token *toke
                 }
             }
             if (level > 0) {
-//                syntaxError(tok);
-                return tok;
+                errorToken=tok;
+				return true;
             }
         }
     }

lib/tokenize.cpp

@@ -7520,6 +7520,8 @@ void Tokenizer::simplifyEnum()
                 break;
             if (Token::Match(temp, "class|struct"))
                 temp = temp->next();
+			if (!temp)
+                break;
             if (!Token::Match(temp, "[{:]") &&
                 (!temp->isName() || !Token::Match(temp->next(), "[{:;]")))
                 continue;
@@ -7529,7 +7531,7 @@ void Tokenizer::simplifyEnum()
             Token *typeTokenEnd = nullptr;
 
             // check for C++11 enum class
-            bool enumClass = isCPP() && Token::Match(tok->next(), "class|struct");
+            const bool enumClass = isCPP() && Token::Match(tok->next(), "class|struct");
             if (enumClass)
                 tok->deleteNext();
 

test/testgarbage.cpp

@@ -88,6 +88,8 @@ private:
         TEST_CASE(garbageCode47); // #6706
         TEST_CASE(garbageCode48); // #6712
         TEST_CASE(garbageCode49); // #6715
+		TEST_CASE(garbageCode50); // #6718
+		TEST_CASE(garbageCode51); // #6719
 
         TEST_CASE(garbageValueFlow);
         TEST_CASE(garbageSymbolDatabase);
@@ -505,6 +507,14 @@ private:
         ASSERT_THROW(checkCode(" ( ( ) ) { } ( { ( __builtin_va_arg_pack ( ) ) ; } ) { ( int { ( ) ( ( ) ) } ( ) { } ( ) ) += ( ) }"), InternalError);
     }
 
+	void garbageCode50() { // #6718
+        checkCode(" enum struct");
+    }
+
+	void garbageCode51() { // #6719
+        checkCode(" (const \"C\" ...); struct base { int f2; base (int arg1, int arg2); }; global_base(0x55, 0xff); { ((global_base.f1 0x55) (global_base.f2 0xff)) { } } base::base(int arg1, int arg2) { f2 = }");
+    }
+
     void garbageValueFlow() {
         // #6089
         const char* code = "{} int foo(struct, x1, struct x2, x3, int, x5, x6, x7)\n"