#4195 segmentation fault of cppcheck (invalid code). Fix segfault which turned up after refactoring the enum handling code.

lib/tokenize.cpp

@@ -7978,6 +7978,8 @@ void Tokenizer::simplifyComma()
                 tok = tok->link()->next();
         }
 
+        if (!tok)
+            syntaxError(nullptr); // invalid code like in #4195
         if (Token::Match(tok, "(|[") ||
             (tok->str() == "{" && tok->previous() && tok->previous()->str() == "=")) {
             tok = tok->link();

test/testgarbage.cpp

@@ -230,6 +230,7 @@ private:
         TEST_CASE(garbageCode179); // #3533
         TEST_CASE(garbageCode180);
         TEST_CASE(garbageCode181);
+        TEST_CASE(garbageCode182); // #4195
         TEST_CASE(garbageValueFlow);
         TEST_CASE(garbageSymbolDatabase);
         TEST_CASE(garbageAST);
@@ -1509,6 +1510,12 @@ private:
     void garbageCode181() {
         checkCode("int test() { int +; }");
     }
+
+    // #4195 - segfault for "enum { int f ( ) { return = } r = f ( ) ; }"
+    void garbageCode182() {
+        ASSERT_THROW(checkCode("enum { int f ( ) { return = } r = f ( ) ; }"), InternalError);
+    }
+
 };
 
 REGISTER_TEST(TestGarbage)

test/testtokenize.cpp

@@ -59,7 +59,6 @@ private:
         TEST_CASE(tokenize20);  // replace C99 _Bool => bool
         TEST_CASE(tokenize21);  // tokenize 0x0E-7
         TEST_CASE(tokenize22);  // special marker $ from preprocessor
-        TEST_CASE(tokenize24);  // #4195 (segmentation fault)
         TEST_CASE(tokenize25);  // #4239 (segmentation fault)
         TEST_CASE(tokenize26);  // #4245 (segmentation fault)
         TEST_CASE(tokenize27);  // #4525 (segmentation fault)
@@ -745,11 +744,6 @@ private:
         ASSERT_EQUALS("$if ( ! p )", tokenizeAndStringify("$if(!p)"));
     }
 
-    // #4195 - segfault for "enum { int f ( ) { return = } r = f ( ) ; }"
-    void tokenize24() {
-        TODO_ASSERT_THROW(tokenizeAndStringify("enum { int f ( ) { return = } r = f ( ) ; }"), InternalError);
-    }
-
     // #4239 - segfault for "f ( struct { int typedef T x ; } ) { }"
     void tokenize25() {
         tokenizeAndStringify("f ( struct { int typedef T x ; } ) { }");