Trait Solver 5 works in nightly

[tkr-sh]

Hello!
The trait solver 5 works in nightly, I don't know which feature makes that possible tho. Maybe it should be precised ?

$ cargo +nightly run
warning: trait `Super` is never used
 --> src/main.rs:1:7
  |
1 | trait Super {}
  |       ^^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: trait `Sub` is never used
 --> src/main.rs:2:7
  |
2 | trait Sub<T>: Super {}
  |       ^^^

warning: trait `Overlap` is never used
 --> src/main.rs:6:7
  |
6 | trait Overlap<T> {}
  |       ^^^^^^^

warning: `_` (bin "_") generated 3 warnings
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.00s
     Running `target/debug/_`

Really nice problem tho!

[BoxyUwU]

I believe this was made to compiler as part of -Znext-solver=coherence stabilization.