Improper use of enum variant gives poor error message

[mdinger]

Similar to #19197 and #17546, this gives a bad error message.
Code:

enum Ty {
    A,
    B(Ty::A),
}

fn main() {}

Error:

<anon>:3:7: 3:12 error: found value name used as a type: DefVariant(DefId { krate: 0u32, node: 4u32 }, DefId { krate: 0u32, node: 5u32 }, false)
<anon>:3     B(Ty::A),
               ^~~~~
playpen: application terminated with error code 101

[pnkfelix]

I just ran into this myself. (At least we give you a span to stare at ...)

[pnkfelix]

triage: P-low