No WRONG_DATA for function pointer with unknown return type (#4893)

Author: chrchr-github

lib/checkfunctions.cpp

@@ -268,7 +268,7 @@ void CheckFunctions::checkIgnoredReturnValue()
             }
 
             if ((!tok->function() || !Token::Match(tok->function()->retDef, "void %name%")) &&
-                !WRONG_DATA(!tok->next()->astOperand1(), tok)) {
+                tok->next()->astOperand1()) {
                 const Library::UseRetValType retvalTy = mSettings->library.getUseRetValType(tok);
                 const bool warn = (tok->function() && tok->function()->isAttributeNodiscard()) || // avoid duplicate warnings for resource-allocating functions
                                   (retvalTy == Library::UseRetValType::DEFAULT && mSettings->library.getAllocFuncInfo(tok) == nullptr);

test/testfunctions.cpp

@@ -1998,6 +1998,11 @@ class TestFunctions : public TestFixture {
               "}\n");
         ASSERT_EQUALS("", errout.str());
 
+        check("void f() {\n"
+              "    INT (*g)() = nullptr;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
         settings = settings_old;
     }