Seg-fault when not providing associated type

[engstad]

This code:

#![feature(globs)]
use std::ops::Add;
struct MyInt { a : int }
impl Add for MyInt {
    fn add(self, rhs:Self) -> Self { MyInt { a : self.a + rhs.a } }
}

fn main(){}

Causes seg-fault:

<anon>:7:1: 9:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 10 }:MyInt.Add, substs=Substs[types=[[];[];[]], regions=[[];[];[]]], nested=[[];[];[]])` did not contain projection for `Obligation(predicate=<MyInt as TraitRef(MyInt, core::ops::Add)>::Output,depth=0)`
<anon>:7 impl Add for MyInt {
<anon>:8     fn add(self, rhs:Self) -> Self { MyInt { a : self.a + rhs.a } }
<anon>:9 }
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /build/rust-git/src/rust/src/libsyntax/diagnostic.rs:123

See http://is.gd/1lKWYa

[nikomatsakis]

I think this is a dup of #20371, which has been fixed. Certainly the example no longer reproduces and the error message is the same.

[nikomatsakis]

(Feel free to re-open if you can still reproduce this on a recent build.)