No completion for string literal in binary equality

[sandersn]

TypeScript Version: nightly (31/1/2017)

Code

type As = 'arf' | 'abacus' | 'abaddon';
let a: As;
if (a === 'ab/**/

Expected behavior:

Two line completion: ["abacus", "abaddon"].

Actual behavior:
File-based symbol completion.

Notes:

1. This works for assignments (a = 'ab/**/) and function calls (f('ab/**/)) already. It should also work for comparisons to make the discriminated union pattern work better.
2. I only tried this in VS Code. But it should probably work anywhere that supports ' as a completion character.