Fixed #1646 (False positive: array access after return cannot have default loop value)

lib/checkother.cpp

@@ -3596,5 +3596,5 @@ void CheckOther::emptyStringTestError(const Token *tok, const std::string &var_n
 void CheckOther::fflushOnInputStreamError(const Token *tok, const std::string &varname)
 {
     reportError(tok, Severity::possibleError,
-        "fflushOnInputStream", "fflush() called on input stream \"" + varname + "\" may result in undefined behaviour");
+                "fflushOnInputStream", "fflush() called on input stream \"" + varname + "\" may result in undefined behaviour");
 }

lib/tokenize.cpp

@@ -4998,6 +4998,10 @@ bool Tokenizer::simplifyKnownVariables()
                         }
                     }
 
+                    // Stop if label is found
+                    if (Token::Match(tok3, "; %type% : ;"))
+                        break;
+
                     if (pointeralias && Token::Match(tok3, ("!!= " + value).c_str()))
                         break;
 

test/testtokenize.cpp

@@ -102,6 +102,7 @@ private:
         TEST_CASE(simplifyKnownVariables22);
         TEST_CASE(simplifyKnownVariables23);
         TEST_CASE(simplifyKnownVariables24);
+        TEST_CASE(simplifyKnownVariables25);
 
         TEST_CASE(match1);
 
@@ -1167,6 +1168,35 @@ private:
             simplifyKnownVariables(code));
     }
 
+    void simplifyKnownVariables25()
+    {
+        // This testcase is related to ticket #1646
+        const char code[] = "void foo(char *str)\n"
+                            "{\n"
+                            "    int i;\n"
+                            "    for (i=0;i<10;++i) {\n"
+                            "        if (*str == 0) goto label;\n"
+                            "    }\n"
+                            "    return;\n"
+                            "label:\n"
+                            "    str[i] = 0;\n"
+                            "}\n";
+
+        // Current result
+        ASSERT_EQUALS(
+            "void foo ( char * str ) "
+            "{"
+            " int i ;"
+            " for ( i = 0 ; i < 10 ; ++ i ) {"
+            " if ( * str == 0 ) { goto label ; }"
+            " }"
+            " return ;"
+            " label : ;"
+            " str [ i ] = 0 ; "
+            "}",
+            simplifyKnownVariables(code));
+    }
+
 
     void match1()
     {