stack overflow with "recursive" trait bound on an associated type

[sellibitze]

I just tried this (last time was 2015-01-08) on playpen:

trait Trait {
    type AssocType: Trait;
}
fn main() {}

which apparently makes rustc do an infinite recursion (or something) ending in a stack overflow:

thread 'rustc' has overflowed its stack
Illegal instruction (core dumped)
playpen: application terminated with error code 132

If I remove the : Trait in the line for the associated type, it works again.

[AndyShiue]

Recursive trait declaration always crashes rustc,
even trait T: T {} can do it...

[carllerche]

cc me

[quantheory]

Note that such traits should probably (?) be accepted, but not all impls of traits can be accepted:

trait Foo {
    type Bar: Foo;
}
// This seems fine.
impl Foo for Baz {
    type Bar = Self;
}
// Problematic
impl<T> Foo for Buzz<T> {
    type Bar = Buzz<Self>;
}

You can make the situation much worse with multiple traits that reference each other, of course. Presumably we have to have some recursion limit that stops types from being infinitely nestable.