ICE when using associated types with lifetimes

[AlexSherbinin]

Code

use std::marker::PhantomData;

pub trait Trait {}

pub trait Foo {
    type Trait: Trait;
    type Bar: Bar;
    fn foo(&mut self);
}

pub struct FooImpl<'a, 'b, A: Trait>(PhantomData<&'a &'b A>);

impl<'a, 'b, T> Foo for FooImpl<'a, 'b, T>
where
    T: Trait,
{
    type Trait = T;
    type Bar = BarImpl<'a, 'b, T>;

    fn foo(&mut self) {
        self.enter_scope(|ctx| {
            BarImpl(ctx);
        });
    }
}

impl<'a, 'b, T> FooImpl<'a, 'b, T>
where
    T: Trait,
{
    fn enter_scope(&mut self, _scope: impl FnOnce(&mut Self)) {}
}
pub trait Bar {
    type Foo: Foo;
}

pub struct BarImpl<'a, 'b, T: Trait>(&'b mut FooImpl<'a, 'b, T>);

impl<'a, 'b, T> Bar for BarImpl<'a, 'b, T>
where
    T: Trait,
{
    type Foo = FooImpl<'a, 'b, T>;
}

Meta

rustc --version --verbose:

rustc 1.80.0-nightly (a8a1d3a77 2024-04-29)
binary: rustc
commit-hash: a8a1d3a771850e1e364eb9010e98789ce758a817
commit-date: 2024-04-29
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.4

Error output

error[E0478]: lifetime bound not satisfied
  --> rustyui/src/lib.rs:18:16
   |
18 |     type Bar = BarImpl<'a, 'b, T>;
   |                ^^^^^^^^^^^^^^^^^^
   |
note: lifetime parameter instantiated with the lifetime `'a` as defined here
  --> rustyui/src/lib.rs:13:6
   |
13 | impl<'a, 'b, T> Foo for FooImpl<'a, 'b, T>
   |      ^^
note: but lifetime parameter must outlive the lifetime `'b` as defined here
  --> rustyui/src/lib.rs:13:10
   |
13 | impl<'a, 'b, T> Foo for FooImpl<'a, 'b, T>
   |          ^^

error: internal compiler error: compiler/rustc_middle/src/ty/generic_args.rs:836:13: Unexpected parameter Type(&'{erased} mut FooImpl<'{erased}, '{erased}, T/#2>) when instantiating in region 'a (index=0)

Backtrace

thread 'rustc' panicked at compiler/rustc_middle/src/ty/generic_args.rs:836:13:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   3: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   4: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   5: rustc_middle::util::bug::bug_fmt
   6: <rustc_middle::ty::generic_args::ArgFolder as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_region::region_param_invalid
   7: <rustc_middle::ty::generic_args::ArgFolder as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_ty
   8: <rustc_middle::ty::generic_args::ArgFolder as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_ty
   9: <rustc_middle::ty::generic_args::ArgFolder as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_ty
  10: <rustc_middle::ty::predicate::Clause as rustc_type_ir::fold::TypeFoldable<rustc_middle::ty::context::TyCtxt>>::try_fold_with::<rustc_middle::ty::generic_args::ArgFolder>
  11: <rustc_middle::ty::generics::GenericPredicates>::instantiate_into
  12: <rustc_middle::ty::generics::GenericPredicates>::instantiate
  13: <rustc_borrowck::MirBorrowckCtxt>::report_general_error
  14: <rustc_borrowck::MirBorrowckCtxt>::report_region_error
  15: rustc_borrowck::do_mir_borrowck
  16: rustc_borrowck::mir_borrowck
      [... omitted 5 frames ...]
  17: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  18: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: please make sure that you have updated to the latest nightly

note: please attach the file at `/home/alex/Projects/Rust/rustyui/rustc-ice-2024-04-30T17_49_51-67262.txt` to your bug report

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED]

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [mir_borrowck] borrow-checking `<impl at rustyui/src/lib.rs:13:1: 15:14>::foo::{closure#0}`
#1 [analysis] running analysis passes on this crate
end of query stack
there was a panic while trying to force a dep node
try_mark_green dep node stack:
#0 mir_borrowck(rustyui[c9e2]::{impl#0}::foo)
end of try_mark_green dep node stack

[lqd]

This looks to be a recent regression from #122213 cc @estebank and is on beta 1.79, but is just in diagnostics.