GDScript 2.0: Can't define nested dictionary and array constants

[vntxx]

Godot version

v4.0.dev.calinou [bfc14a6]

System information

Windows 10

Issue description

Upon defining a nested dictionary constant the editor will mark it as an error. It does, however, work when defining the inner dictionary (as a constant) beforehand. Not sure whether this is by design but it did work in GDScript 1.0 (Godot 3.x) so I'm guessing this may be a bug.

Steps to reproduce

Define a nested dictionary as a constant inside a GDScript file (see below)

Minimal reproduction project

Create a new GDScript file inside the engine and paste the following:

const CONST_DICTIONARY = {
	"key1": "value1",
	"key2": "value2",
}

const CONST_NESTED_DICTIONARY = { # Error
	"key1": "value1",
	"key2": { "key": true }
}

const CONST_INNER_DICTIONARY = { "key": true }
const CONST_NESTED_DICTIONARY_WORKAROUND = {
	"key1": "value1",
	"key2": CONST_INNER_DICTIONARY
}

[lyuma]

It also happens for nested arrays.

Example reproduction case provided by @Scony in #52031

Godot version

master #fb176d5f6e6dc2b43c630a041a8ab7d737173ec4

System information

manjaro linux

Issue description

following script:

const X = {
	'x': [],
}

yields

SCRIPT ERROR: Parse Error: Initializer for a constant must be a constant expression.
          at: GDScript::reload (res://tests/potential-godot-bugs/const-dict.gd:1)
ERROR: Method/function failed. Returning: ERR_PARSE_ERROR
   at: reload (modules/gdscript/gdscript.cpp:840)

while it was working in Godot 3.x