Can you reframe the remaining problems as a new ticket? The original GROOVY-9288 issue should be fixed in my estimation.

Also, you have test cases disabled with a boolean switch. Can you use @ignore or @NotYetImplemented to disable them? And do you expect those test cases to work? It was unclear if they indicate a different problem or unsolved part of the current issue.

Even if the fix for GROOVY-7996 was rolled back, protected field can not be accessed via thisObject, owner and delegate : #1046 (comment)
So the original description of GROOVY-9288 have to be refined too.

Here is another take on your change that checks protected and package-private access for the closure's enclosing type.

                if (field != null && !field.isPublic()
                        && objectExpression instanceof VariableExpression
                        && typeCheckingContext.getEnclosingClosure() != null
                        && (
                            (field.isProtected() && typeCheckingContext.getEnclosingClassNode().isDerivedFrom(current))
                             ||
                            (!field.isPrivate() && Objects.equals(typeCheckingContext.getEnclosingClassNode().getPackageName(), current.getPackageName()))
                           )
                ) {
                    switch (objectExpression.getText()) {
                    case "it":
                    case "owner":
                    case "delegate":
                    case "thisObject":
                        pexp.putNodeMetaData(DYNAMIC_RESOLUTION, Boolean.TRUE);
                    }
                }

I'm still not too keen on dynamic properties. But at least this should stop conversion of forbidden access to missing property. What does not match up is that explicit-this and implicit-this don't produce compiler errors, but instead result in missing property exceptions. I'm just not sure if we know enough to proceed on a change...

@eric-milles Let's make it work, then work better, at last work perfectly ;-)

Replaced with #1050

@eric-milles BTW, I will add your tweak in PR #1050 with your commit info reserved

@eric-milles After your patch applied, the following tests fails, so I will keep the original PR as it is for now:

@eric-milles parts of your patch is applied: ae0bc9f