Typehints on inner classes do not recognize function argument types

[bitbrain]

Godot version

9c9b8fc

System information

Windows 10

Issue description

I use a lot of inner classes in my project to structure my data better and in Godot 3.5+ I was able to instantiate an inner class and use it as a function argument type. Attempting this in Godot 4 results in a compilation error:

Invalid type in function '_print_string_value' in base 'Node2D ()'. The Object-derived class of argument 1 (RefCounted (ChildClassA)) is not a subclass of the expected argument class.

This line comes from

godot/modules/gdscript/gdscript_vm.cpp

Line 166 in 7199314

err_text = "Invalid type in " + p_where + ". The Object-derived class of argument " + itos(errorarg + 1) + " (" + _get_var_type(argptrs[errorarg]) + ") is not a subclass of the expected argument class.";

and when debugging the project it looks like there is not a real type created but just a RefCounted:

This might relate to #61567 and #61635 however, they mention very specific use-cases while I am just trying to use the type itself.

Steps to reproduce

Create some inner classes with inheritance and then register that namespace class as a autoload singleton:

Attempt to use the inner classes as types:

Minimal reproduction project

gdscript-inner-classes.zip

[olibombardier]

I have the same issue, the workaround I found was to explicitly convert to the subclass when passing an argument to a method. (_print_string_value(class1 as MyNamespace.MyParentClass) would probably work)

[olibombardier]

Turns out I was wrong, converting to the subclass returns null. With other corrections I needed to make to convert to Godot 4 I didn't realise that this was the cause of one of my bug. Should I open another bug report? It might be the same problem where some part of gdscript doesn't recognize an instance of a subclass as that

[adamscott]

This seems, at first glance, linked to #65953, where the base class is not set well. I will try to investigate this.

[lyuma]

There have been issues with inner classes and type declarations before.
There are also issues I filed last year #47062 and #47063, both of which were fixed by #49105

But I was able to reproduce a similar issue here by referencing an inner class from a different file.

SCRIPT ERROR: Trying to assign value of type '' to a variable of type 'external_type.gd'.
          at: _enter_tree (res://addons/imported_type_test/plugin.gd:14)
SCRIPT ERROR: Trying to assign value of type '' to a variable of type 'inner_classes.gd'.
          at: _enter_tree (res://addons/inner_class_decl/plugin.gd:14)

here's a test project for this if you want to try it (see the versions : Object work fine, but type hints break it):
ImportedTypeDecl.zip

[adamscott]

@lyuma I can't test right now, but can you test your project against my cyclic references PR #67714? It fixes this issue.

[rune-scape]

tested that #68374 fixes this