ICE in deconstruct_pat.rs: Unexpected type for Single constructor

[sunshowers]

STR:

git clone https://github.com/facebookincubator/cargo-guppy
cd cargo-guppy
git checkout 6c73fe86e06f60431598c6df8b965b775826a1f7
cargo +nightly check -p guppy-summaries

Error output

error: internal compiler error: compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs:1191:22: Unexpected type for `Single` constructor: <summary::PackageInfo as diffus::Diffable>::Diff

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1146:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

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 1.57.0-nightly (aa7aca3b9 2021-09-30) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [check_match] match-checking `diff::<impl at guppy-summaries/src/diff.rs:123:1: 236:2>::new`
#1 [analysis] running analysis passes on this crate
end of query stack

Backtrace

   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_errors::HandlerInner::bug
   3: rustc_errors::Handler::bug
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_mir_build::thir::pattern::deconstruct_pat::DeconstructedPat::specialize
   8: rustc_mir_build::thir::pattern::usefulness::is_useful
   9: rustc_mir_build::thir::pattern::usefulness::is_useful
  10: rustc_mir_build::thir::pattern::usefulness::compute_match_usefulness
  11: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  12: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  13: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  14: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  15: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  16: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  17: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  18: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  19: rustc_mir_build::thir::pattern::check_match::check_match
  20: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  21: rustc_data_structures::stack::ensure_sufficient_stack
  22: rustc_query_system::query::plumbing::try_execute_query
  23: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_match
  24: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  25: rustc_session::utils::<impl rustc_session::session::Session>::time
  26: rustc_session::utils::<impl rustc_session::session::Session>::time
  27: rustc_interface::passes::analysis
  28: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  29: rustc_data_structures::stack::ensure_sufficient_stack
  30: rustc_query_system::query::plumbing::try_execute_query
  31: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  32: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  33: rustc_span::with_source_map
  34: scoped_tls::ScopedKey<T>::set

This bisected to #88950.

searched nightlies: from nightly-2021-08-01 to nightly-2021-10-01
regressed nightly: nightly-2021-09-30
searched commits: from 8f8092c to 1149193
regressed commit: 6df1d82

bisected with cargo-bisect-rustc v0.6.0

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start=2021-08-01 -- check -p guppy-summaries 

[eddyb]

cc @Nadrieril To me <summary::PackageInfo as diffus::Diffable>::Diff looks like a missing normalization.

[sunshowers]

Ahh, looks like a duplicate of #89393