Fixed #5080 ((error) Internal error. Token::Match called with varid 0. Please report this to Cppcheck developers)

lib/checknullpointer.cpp

@@ -520,6 +520,10 @@ void CheckNullPointer::nullPointerLinkedList()
                 // Variable id for dereferenced variable
                 const unsigned int varid(tok2->varId());
 
+                // We don't support variables without a varid
+                if (varid == 0)
+                    continue;
+
                 if (Token::Match(tok2->tokAt(-2), "%varid% ?", varid))
                     continue;
 

test/testnullpointer.cpp

@@ -75,6 +75,7 @@ private:
         TEST_CASE(functioncalllibrary); // use Library to parse function call
         TEST_CASE(crash1);
         TEST_CASE(functioncallDefaultArguments);
+        TEST_CASE(nullpointer_internal_error); // #5080
     }
 
     void check(const char code[], bool inconclusive = false, const char filename[] = "test.cpp", bool verify=true) {
@@ -2320,6 +2321,17 @@ private:
               "    return if\n"
               "}");
     }
+
+    void nullpointer_internal_error() { // ticket #5080
+        check("struct A { unsigned int size; };\n"
+              "struct B { struct A *a; };\n"
+              "void f(struct B *b) {\n"
+              "    unsigned int j;\n"
+              "    for (j = 0; j < b[0].a->size; ++j) {\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
 };
 
 REGISTER_TEST(TestNullPointer)