Existence of trait alias breaks name resolution of associated consts

[matthew-mcallister]

On 1.45.0-nightly (a74d1862d 2020-05-14), this trait definition/impl works fine:

trait Bounded { const MAX: Self; }

impl Bounded for u32 {
    const MAX: Self = u32::MAX;
}

Here, u32::MAX resolves unambiguously to the associated const on u32.

If I merely define a trait alias that uses Bounded:

#![feature(trait_alias)]

trait Bounded { const MAX: Self; }

impl Bounded for u32 {
    const MAX: Self = u32::MAX;
}

trait Num = Bounded + Copy;

I get this error:

error[E0034]: multiple applicable items in scope
 --> src/lib.rs:6:28
  |
6 |     const MAX: Self = u32::MAX;
  |                       -----^^^
  |                       |    |
  |                       |    multiple `MAX` found
  |                       help: disambiguate the associated constant for candidate #1: `Bounded::MAX`
  |
note: candidate #1 is defined in an impl of the trait `Bounded` for the type `u32`
 --> src/lib.rs:6:5
  |
6 |     const MAX: Self = u32::MAX;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  = note: candidate #2 is defined in an impl for the type `u32`

[matthew-mcallister]

Looks related to #60021.