impl Trait lifetimes regression 1.67

[aliemjay]

Some regressions of #103491 that I previously reported in #105826 (comment), but they were missed:

struct MyTy<'a>(Vec<u8>, &'a ());

impl MyTy<'_> {
    fn one(&mut self) -> &mut impl Sized {
        &mut self.0
    }
    fn two(&mut self) -> &mut (impl Sized + 'static) {
        self.one()
        //~^ ERROR lifetime may not live long enough
    }
}

#![feature(type_alias_impl_trait)]
type Opaque<'a> = impl Sized;
fn define<'a>() -> Opaque<'a> {}

fn test<'a>() {
    None::<&'static Opaque<'a>>;
    //~^ ERROR lifetime may not live long enough
}

fn one<'a, 'b: 'b>() -> &'a impl Sized {
    &()
}
fn two<'a, 'b>() {
    one::<'a, 'b>();
    //~^ ERROR lifetime may not live long enough
}

I guess the way to fix this is to ignore non-captured lifetimes of opaque types here

rust/compiler/rustc_infer/src/infer/outlives/obligations.rs

Line 417 in ca1bc7f

fn substs_must_outlive(

cc @cjgillot

@rustbot label C-bug regression-from-stable-to-stable T-types T-compiler A-impl-trait

[apiraino]

WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-high