jump-to-definition doesn't appear to work in assoc type bounds

[nikomatsakis]

In Chalk, I have some code like this

trait Foo {
    type Bar: Bar;
    //        ^^^ cursor here
}

trait Bar: Copy + Clone {
}

when I put the cursor on Bar and hit jump-to-def, it doesn't go anywhere. =) This seems to be true in the simplest of projects.

[nikomatsakis]

The problem can be observed in this repository:

https://github.com/nikomatsakis/rls-778

Also:

> rustc -vV
rustc 1.26.0-nightly (2789b067d 2018-03-06)
binary: rustc
commit-hash: 2789b067da2ac921b86199bde21dd231ace1da39
commit-date: 2018-03-06
host: x86_64-apple-darwin
release: 1.26.0-nightly
LLVM version: 6.0

[nrc]

Tracked in rust-dev-tools/rls-analysis#140