Don't ICE when computing PointerLike trait when region vars are in param-env

[compiler-errors]

Fixes #111877

[rustbot]

r? @oli-obk

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[rustbot]

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

[jackh726]

Why erase rather than just checking if the goal has any infer?

[compiler-errors]

@jackh726: There's no reason to treat this goal as ambiguous just because our param-env has early bound regions that get canonicalized into region vars. If we treated the presence of region vars as ambiguous, then something this would fail for no particularly good reason:

fn is_pointer_like<T: PointerLike>(_: T) {}

fn foo<T: 'a>() {
  let x: &'static () = &();
  is_pointer_like(x);
}

To put it in other words, layout computation is done modulo regions anyways.

[jackh726]

@bors r+

[bors]

📌 Commit 3a2710c has been approved by jackh726

It is now in the queue for this repository.

[lcnr]

that should ICE with non lifetime binders 🤔 also just style (and irrelevant perf) would prefer to first check for non_region_infer in the ParamEnvAnd and then erase regions.