ICE: Infinite Recursion when compiling recursive type

[arielb1]

The following code causes infinite recursion in rustc:

struct Omega<T>(Vec<Omega<Option<T>>>);
fn main () {}

version: rustc 0.12.0-pre (2f9669c74 2014-09-23 12:45:45 +0000), and also today's play.rust-lang.org

The recursion seems to be between various lines of middle::ty::type_contents::tc_ty.

Note that the following code compiles (note Box instead of Vec):

struct Omega<T>(Box<Omega<Option<T>>>);
fn tickle<T>(r: ||->Omega<T>) {}
fn main () {}

but if you add

fn basilisk<T>(r: Option<Omega<T>>) {}

the crash happens again

[arielb1]

Seems to be a dupe of #17431.

[isabelmu]

I believe this is a dupe of #4363, since Omega is representable and instantiable (both with Vec and with Box), but causes infinite type generation.

[ghost]

Indeed, closing as a dupe of #4363. Thanks @typelist!