Overflow evaluating the requirement with GATS

[agluszak]

I tried this code:
https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=0ed2d890d6c301d7d07d6fbdb061d34e

I expected to see this happen: compilation success

Instead, this happened:

Compiling playground v0.0.1 (/playground)
error[[E0275]](https://doc.rust-lang.org/nightly/error-index.html#E0275): overflow evaluating the requirement `Option<List<Optionize>>: Debug`
  --> src/main.rs:36:22
   |
36 |     println!("{:?}", output);
   |                      ^^^^^^
   |
note: required for `List<Optionize>` to implement `Debug`
  --> src/main.rs:18:10
   |
18 | #[derive(Debug)]
   |          ^^^^^
   = note: 1 redundant requirement hidden
   = note: required for `Option<List<Optionize>>` to implement `Debug`
note: required by a bound in `ArgumentV1::<'a>::new_debug`
   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `arg_new` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0275`.
error: could not compile `playground` due to previous error

rustc --version --verbose:

1.67.0-nightly

(2022-11-26 80a96467ec5675e9f696)

Probably related:
#85063, #39959, #96634

But I guess this is a bit different, because GATs are involved?

[VladimirBramstedt]

yeah, i ran into a similar issue, with a more trivial example:

trait Foo { type Bar<T>; }

struct Tester;
impl Foo for Tester {
    type Bar<T> = Vec<T>;
}

struct Testy {
  rep: <Tester as Foo>::Bar<Testy>
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=3a5f31004b9c3ac56b9aa7d9219b6753

im guessing the compiler tries to dive down the recursive type here forever and overflows...

[agluszak]

@VladimirBramstedt looks like your simpler example was fixed at some point (it compiles with the current nightly), but mine still throws the same error