regression: lifetime under _for all_ does not appear in the trait input types

[ABorgna]

Code

pub trait TraitWithGAT {
    type T<'c>;
}

pub trait FnLike<'c, TM: TraitWithGAT>: Fn(TM::T<'c>) -> TM::T<'c> {}

pub trait StaticFnLike<TM: TraitWithGAT>: for<'c> FnLike<'c, TM> {}

pub struct DynTraitObject<TM: TraitWithGAT>(pub dyn StaticFnLike<TM>);

On stable, cargo build compiles without errors.

On beta (and nightly 2024-10-20), it fails with the following error:

error[E0582]: binding for associated type `Output` references lifetime `'c`, which does not appear in the trait input types
 --> src/trait_beta_bug.rs:9:53
  |
5 | pub trait FnLike<'c, TM: TraitWithGAT>: Fn(TM::T<'c>) -> TM::T<'c> {}
  |                                                          --------- due to this supertrait
...
9 | pub struct DynTraitObject<TM: TraitWithGAT>(pub dyn StaticFnLike<TM>);
  |                                                     ^^^^^^^^^^^^^^^^

For more information about this error, try `rustc --explain E0582`.

playground

Version it worked on

rustc --version --verbose:

rustc 1.82.0 (f6e511eec 2024-10-15)
binary: rustc
commit-hash: f6e511eec7342f59a25f7c0534f1dbea00d01b14
commit-date: 2024-10-15
host: aarch64-apple-darwin
release: 1.82.0
LLVM version: 19.1.1

Version with regression

rustc +beta --version --verbose:

rustc 1.83.0-beta.2 (88c1c3c11 2024-10-18)
binary: rustc
commit-hash: 88c1c3c1102bbf3860891bfa52b7ddd9f26aec2f
commit-date: 2024-10-18
host: aarch64-apple-darwin
release: 1.83.0-beta.2
LLVM version: 19.1.1

@rustbot modify labels: +regression-from-stable-to-beta -regression-untriaged

[compiler-errors]

This is very likely unsound in the same way that for<'a> Fn(T::Assoc<'a>) -> T::Assoc<'a> is unsound as a supertrait bound.