Can't `impl Trait<i32> for dyn Trait<i64>`

I tried this code:

trait Trait<T> {}

impl Trait<i32> for dyn Trait<i64> {}

I expected the code to compile, but I got this error instead:

error[E0371]: the object type `(dyn Trait<i64> + 'static)` automatically implements the trait `Trait`
 --> src/lib.rs:3:1
  |
3 | impl Trait<i32> for dyn Trait<i64> {}
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `(dyn Trait<i64> + 'static)` automatically implements trait `Trait`

For more information about this error, try `rustc --explain E0371`.

I'm not sure if this is useful to allow, but I do find it strange that it's prohibited.

Even though we're implementing the trait on a trait object of that "same" trait, the generic parameter is different, so there should be no overlap.

Meta

Reproducible on the playground with version 1.95.0-nightly (2026-02-04 db3e99bbab28c6ca778b)

Reproduce the Rust snippet in the linked playground and read the rustc --explain E0371 output first. Investigate how trait objects and generic trait implementations are handled, then determine whether this impl should be accepted; done requires a decided language behavior with corresponding compiler coverage.