"Type annotations needed" with mixed lifetimes in trait bounds

[arcnmx]

This was encountered from a derive plugin that created where bounds for all member types. Occurs on stable, beta, and nightly.

struct S<'a>(&'a ());

trait Tr { }
impl<T> Tr for Option<T> { }
impl<'a> Tr for S<'a> where Option<&'a str>: Tr, Option<&'static str>: Tr { }

error: mismatched types [--explain E0308]
 --> <anon>:5:1
  |>
5 |> impl<'a> Tr for S<'a> where Option<&'a str>: Tr, Option<&'static str>: Tr { }
  |> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetime mismatch
note: expected type `Tr`
note:    found type `Tr`
note: the lifetime 'a as defined on the impl at 5:0...
 --> <anon>:5:1
  |>
5 |> impl<'a> Tr for S<'a> where Option<&'a str>: Tr, Option<&'static str>: Tr { }
  |> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...does not necessarily outlive the static lifetime

error: aborting due to previous error

playpen repro

[estebank]

Doesn't repro anymore with the linked code.

[jackh726]

Error on latest stable:

error[E0283]: type annotations required: cannot resolve `std::option::Option<&'a str>: Tr`
 --> src/main.rs:5:1
  |
5 | impl<'a> Tr for S<'a> where Option<&'a str>: Tr, Option<&'static str>: Tr { }
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
note: required by `Tr`
 --> src/main.rs:3:1
  |
3 | trait Tr { }
  | ^^^^^^^^

[lcnr]

Minimal repro:

trait Foo {}
impl<'a, T> Foo for &'a T {}

// we need `'a _` and `'static _` in the same
// `where` bound afaict.
struct Ctx<'a>(&'a ()) where
    &'a (): Foo,
    &'static (): Foo;

While this is a quite rare edge case, the error is very unhelpful rn 😅