stack-overflow bug: A nested record can't be it's interface parent

[Andre-LA]

The code below crashes the compiler on a stack overflow on the close_nested_records function:

local interface X
   record A is X
   end
end

Teal version: 0.24.1

[mtdowling]

This is somewhat related to #870. We might want to just forbid nesting records in interfaces since interfaces don't generate code.

[hishamhm]

The bug also happened with nested interfaces. I made a small tweak so that it doesn't crash anymore, but I'm wondering if other weird behaviors might come up from it.

Is there a real-life use-case for an inner interface that extends its outer interface? I'm afraid such circular types will start causing other problems...

[Andre-LA]

Is there a real-life use-case for an inner interface that extends its outer interface? I'm afraid such circular types will start causing other problems

Maybe due to exporting to other modules?

interA.tl:

local interface A
	a: integer

	interface B is A
		b: string
	end
end

return A

test.tl:

local type A = require 'interA'

local x: A.B = {
	a = 10,
	b = 'hello'
}

print(x.a, x.b) --> 10	hello

[hishamhm]

@Andre-LA this still looks like a "synthetic" example, I'm afraid...

[mtdowling]

FWIW, you can nest interfaces like this is Java. It’s solely used for grouping.

[hishamhm]

Nesting interfaces is supported. Having the nested one its own parent (producing a circular nesting once the inner interface is resolved) is the thing I'm finding odd here.