rustc ICEs when an impl doesn't have all the methods it needs to

[jld]

At revision ce4e09b. A minimized test case:

enum thing = uint;
impl thing : cmp::Ord {
    pure fn lt(&&other: thing) -> bool { *self < *other }
}

Looking up some of the addresses from the backtrace in nm -n output (is there a better way to do this?) suggests that it's the tcx.items.get in middle::typeck::collect::check_methods_against_trait.

[catamorphism]

I'll look at this.