ICE: broken MIR with impl_trait_in_bindings

[aticu]

Originally found in #85883 by @Boddlnagg. At first I thought this was #85113, but it turned out to be something else, so as @JohnTitor requested, I'm opening a new issue for it, since it didn't seem like one already existed for it.

Code

#![feature(unboxed_closures)]
#![feature(min_type_alias_impl_trait)]
#![feature(impl_trait_in_bindings)]

type FunType = impl Fn<()>;
static STATIC_FN: FunType = some_fn;

fn some_fn() {}

fn main() {
    let _: <FunType as FnOnce<()>>::Output = STATIC_FN();
}

Meta

rustc --version --verbose:

rustc 1.54.0-nightly (eab201df7 2021-06-09)
binary: rustc
commit-hash: eab201df7028ebb6812c0b1a01702ac6ecfcceed
commit-date: 2021-06-09
host: x86_64-unknown-linux-gnu
release: 1.54.0-nightly
LLVM version: 12.0.1

Error output

error: internal compiler error: broken MIR in DefId(0:7 ~ tmp[8939]::main) (NoSolution): failed to normalize `<_ as std::ops::FnOnce<()>>::Output`
  |
  = note: delayed at compiler/rustc_mir/src/borrow_check/type_check/mod.rs:253:27

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', compiler/rustc_errors/src/lib.rs:1023:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

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: rustc 1.54.0-nightly (eab201df7 2021-06-09) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type bin

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

query stack during panic:
end of query stack

Backtrace

   0: rust_begin_unwind
             at /rustc/eab201df7028ebb6812c0b1a01702ac6ecfcceed/library/std/src/panicking.rs:515:5
   1: std::panicking::begin_panic_fmt
             at /rustc/eab201df7028ebb6812c0b1a01702ac6ecfcceed/library/std/src/panicking.rs:457:5
   2: rustc_errors::HandlerInner::flush_delayed
   3: <rustc_errors::HandlerInner as core::ops::drop::Drop>::drop
   4: core::ptr::drop_in_place<rustc_session::parse::ParseSess>
   5: <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop
   6: core::ptr::drop_in_place<rustc_interface::interface::Compiler>
   7: rustc_span::with_source_map
   8: rustc_interface::interface::create_compiler_and_run
   9: rustc_span::with_session_globals

[aticu]

@rustbot label: +F-type_alias_impl_trait +F-impl_trait_in_bindings +F-unboxed_closures +requires-nightly