1.98 beta regression: "cannot deduce the lifetime bound for this trait object type from context"

[theemathas]

This regression was found by the 1.98 beta crater run.

[INFO] [stdout] error[E0228]: cannot deduce the lifetime bound for this trait object type from context
[INFO] [stdout]    --> src/experiment/mod.rs:255:41
[INFO] [stdout]     |
[INFO] [stdout] 255 |         type IntoIter<'a> = T::Iter<'a, dyn Example>
[INFO] [stdout]     |                                         ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout] help: please supply an explicit bound
[INFO] [stdout]     |
[INFO] [stdout] 255 |         type IntoIter<'a> = T::Iter<'a, dyn Example + /* 'a */>
[INFO] [stdout]     |                                                     ++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0228`.

• https://crater-reports.s3.amazonaws.com/beta-1.98-4/1.98.0-beta.1/gh/asafigan.impl-iter-tuple-kind-of/log.txt

[theemathas]

Minimized:

pub trait Example {}

pub trait AsIter {
    type Iter<T: ?Sized>;
}

pub trait ExampleList {
    type IntoIter;
}

impl<T: AsIter> ExampleList for T {
    type IntoIter = T::Iter<dyn Example>;
}

Error output on beta:

error[E0228]: cannot deduce the lifetime bound for this trait object type from context
  --> src/lib.rs:12:29
   |
12 |     type IntoIter = T::Iter<dyn Example>;
   |                             ^^^^^^^^^^^
   |
help: please supply an explicit bound
   |
12 |     type IntoIter = T::Iter<dyn Example + /* 'a */>;
   |                                         ++++++++++

For more information about this error, try `rustc --explain E0228`.
error: could not compile `foo` (lib) due to 1 previous error

[theemathas]

Bisection result:

searched toolchains 3bf5c6d99bc8a0c0d5b2f69826ed4f6d256a0a21 through 7148b31956911d5d5496900bf564ca5212bf199b


********************************************************************************
Regression in d56483a91d6cf5041351a3208b8d08f98f0c8b56
********************************************************************************

Attempting to search unrolled perf builds
ERROR: couldn't find perf build comment

Regressed in #129543. cc @fmease, @lcnr