Singleton's cannot be used as const in a module

[chucklepie]

Godot version:
3.2.3

OS/device including version:
Linux

Issue description:
I know enums don't work very well with singletons/exports but I have the following in an autoload:

const COLOURS = { 
	"black" 		: [0.0,0.0,0.0],
	"blue" 			: [0.0,0.0,192.0/256.0]
}

If I try to create a constant using it:

var y = Globals.COLOURS.blue     #works fine as var
const z = Globals.COLOURS.blue

I get error invalid index COLOURS in constant expression.

Maybe this is more a 'feature request', but you would expect autoload variables to be loaded first or at least a script able to know of the autoload's existence as it parses the code...

[Calinou]

A singleton reference is not constant because the first part (Globals) is a result of get_node(), which itself is not a constant expression. I wouldn't consider this to be a bug.

Stuff like this could be solved by introducing immutable variables, but it's not likely to happen soon.

[chucklepie]

I get what you're saying, but constants are "known at compile-time" according to the docs, which implies it is defined regardless where it is declared, it is simply known at compile time?

So an autoload having a constant means the value is known at compile time. So that implies that a const based off a const is also perfectly valid because that is done at compile time?

[omicron321]

why use globals, when you can do MyClass.MY_CONST

[KoBeWi]

Autoloads are just references to a node. They can be modified, removed or replaced, so they can't be const.

However your code will work just fine when you add class_name.