Fixed #2604 (Segmentation fault of cppcheck ( sizeof <= A ))

lib/tokenize.cpp

@@ -3918,10 +3918,14 @@ void Tokenizer::simplifySizeof()
                     --parlevel;
                 if (Token::Match(tempToken, "%var%"))
                 {
-                    while (tempToken->next()->str() == "[")
+                    while (tempToken && tempToken->next() && tempToken->next()->str() == "[")
                     {
                         tempToken = tempToken->next()->link();
                     }
+                    if (!tempToken || !tempToken->next())
+                    {
+                        break;
+                    }
 
                     if (tempToken->next()->str() == ".")
                     {

test/testsimplifytokens.cpp

@@ -85,6 +85,7 @@ private:
         TEST_CASE(sizeof20);    // #2024 - sizeof a)
         TEST_CASE(sizeof21);    // #2232 - sizeof...(Args)
         TEST_CASE(sizeof22);    // #2599
+        TEST_CASE(sizeof23);    // #2604
         TEST_CASE(sizeofsizeof);
         TEST_CASE(casting);
 
@@ -1433,6 +1434,15 @@ private:
         tok(code);
     }
 
+    void sizeof23()
+    {
+        // ticket #2604 segmentation fault
+        const char code[] = "sizeof <= A\n";
+
+        // don't segfault
+        tok(code);
+    }
+
 
     void sizeofsizeof()
     {