diff --git a/lib/templatesimplifier.cpp b/lib/templatesimplifier.cpp
index 3c496ede1..fc6910582 100644
--- a/lib/templatesimplifier.cpp
+++ b/lib/templatesimplifier.cpp
@@ -212,12 +212,13 @@ bool TemplateSimplifier::hasComplicatedSyntaxErrorsInTemplates(const Token *toke
             }
             if (level > 0) {
                 errorToken=tok;
+                syntaxError(tok);
                 return true;
             }
         }
     }
 
-    return 0;
+    return false;
 }
 
 unsigned int TemplateSimplifier::templateParameters(const Token *tok)
@@ -1421,7 +1422,7 @@ void TemplateSimplifier::simplifyTemplates(
                 templates2.push_back(*iter1);
         }
 
-        for (std::list<Token *>::iterator it = templates2.begin(); it != templates2.end(); ++it) {
+        for (std::list<Token *>::const_iterator it = templates2.begin(); it != templates2.end(); ++it) {
             std::list<Token *>::iterator it1 = std::find(templates.begin(), templates.end(), *it);
             if (it1 != templates.end()) {
                 templates.erase(it1);
@@ -1430,3 +1431,8 @@ void TemplateSimplifier::simplifyTemplates(
         }
     }
 }
+
+void TemplateSimplifier::syntaxError(const Token *tok)
+{
+    throw InternalError(tok, "syntax error", InternalError::SYNTAX);
+}
diff --git a/lib/templatesimplifier.h b/lib/templatesimplifier.h
index 4dbbe6bcc..66abf017b 100644
--- a/lib/templatesimplifier.h
+++ b/lib/templatesimplifier.h
@@ -187,6 +187,9 @@ private:
      */
     static bool removeTemplate(Token *tok);
 
+    /** Syntax error */
+    static void syntaxError(const Token *tok);
+
 };
 
 /// @}
diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index fd8ddc36d..39ab327e5 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -973,14 +973,12 @@ void Tokenizer::simplifyTypedef()
             argEnd = tokOffset->link();
 
             argFuncRetStart = argEnd->tokAt(2);
-            if (!argFuncRetStart)
-            {
+            if (!argFuncRetStart) {
                 syntaxError(tokOffset);
                 return;
             }
             argFuncRetEnd = argFuncRetStart->link();
-            if (!argFuncRetEnd)
-            {
+            if (!argFuncRetEnd) {
                 syntaxError(tokOffset);
                 return;
             }
@@ -994,14 +992,12 @@ void Tokenizer::simplifyTypedef()
             argEnd = tokOffset->link();
 
             argFuncRetStart = argEnd->tokAt(2);
-            if (!argFuncRetStart)
-            {
+            if (!argFuncRetStart) {
                 syntaxError(tokOffset);
                 return;
             }
             argFuncRetEnd = argFuncRetStart->link();
-            if (!argFuncRetEnd)
-            {
+            if (!argFuncRetEnd) {
                 syntaxError(tokOffset);
                 return;
             }
@@ -7537,8 +7533,10 @@ void Tokenizer::simplifyEnum()
             ++classLevel;
         } else if (tok->str() == "enum") {
             Token *temp = tok->next();
-            if (!temp)
+            if (!temp) {
+                syntaxError(tok);
                 break;
+            }
             if (Token::Match(temp, "class|struct"))
                 temp = temp->next();
             if (!temp)
diff --git a/test/testsimplifytokens.cpp b/test/testsimplifytokens.cpp
index cdbd55853..dd523a604 100644
--- a/test/testsimplifytokens.cpp
+++ b/test/testsimplifytokens.cpp
@@ -3278,8 +3278,7 @@ private:
 
     void enum26() { // ticket #2975 (segmentation fault)
         const char code[] = "enum E {} e enum\n";
-        checkSimplifyEnum(code);
-        ASSERT_EQUALS("", errout.str());
+        ASSERT_THROW(checkSimplifyEnum(code), InternalError);
     }
 
     void enum27() { // ticket #3005 (segmentation fault)