resolve failure when setting enum discriminator to a declared const

[msullivan]

const foo: int = 4 >> 1;
enum bs { thing = foo }
fn main() { assert(thing as int == foo); }

fails with

resolve-bug.rs:4:18: 4:21 error: internal error looking up a definition
resolve-bug.rs:4 enum bs { thing = foo }

[catamorphism]

Test this again when #1935 is completed.

[bstrie]

Still hitting this error despite new resolve.

[catamorphism]

I've fixed this, just waiting for the tree to be open again.