Tracking issue for future-incompatbility lint `ambiguous_associated_items`

[petrochenkov]

What is this lint about

With variants being resolved as inherent associated items (rust-lang/rfcs#2338) code like this become ambiguous:

enum E {
    V
}

trait Tr {
    type V;
    fn f() -> Self::V;
}

impl Tr for E {
    type V = u8;
    fn f() -> Self::V { 0 } // `Self::V` in type namespace may refer to both variant and associated type
}

This is not a problem right now, because variants cannot be used in type positions, but it may become a problem in the future if rust-lang/rfcs#2593 is accepted.
So this lints warns against cases like this and recommends to rewrite them as <Self as Tr>::V.

How to fix this warning/error

Explicitly disambiguate in favor of associated types from traits: <Type as Trait>::Ambiguous.

Current status

• High priority resolutions for associated variants #57501 introduces the ambiguous_associated_items lint as warn-by-default
• Make deprecation lint ambiguous_associated_items deny-by-default #59928 makes the ambiguous_associated_items lint deny-by-default
• PR ? makes the ambiguous_associated_items lint a hard error