ICE: multiple @ bindings of slice patterns, e.g. [a @ .., b @ ..]

[memoryruins]

Code

fn main() {
    let [a @ .., b @ ..] = &mut [1, 2];
    b;
}

The ICE only occurs when b is used.
playground

Meta

rustc 1.43.0-nightly (fc23a8183 2020-02-11)
x86_64-unknown-linux-gnu

Error output

   Compiling playground v0.0.1 (/playground)
error: `..` can only be used once per slice pattern
 --> src/main.rs:2:22
  |
2 |     let [a @ .., b @ ..] = &mut [1, 2];
  |              --      ^^ can only be used once per slice pattern
  |              |
  |              previously used here

error: internal compiler error: src/librustc_typeck/check/mod.rs:2975: no type for local variable pat _ (hir_id=HirId { owner: DefIndex(3), local_id: 3 })
 --> src/main.rs:3:5
  |
3 |     b;
  |     ^

thread 'rustc' panicked at 'Box<Any>', <::std::macros::panic macros>:2:4

Backtrace

thread 'rustc' panicked at 'Box<Any>', <::std::macros::panic macros>:2:4
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:77
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1052
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1428
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:204
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:224
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:474
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::span_bug
  14: rustc_errors::Handler::span_bug
  15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc::ty::context::tls::with_opt::{{closure}}
  17: rustc::ty::context::tls::with_opt
  18: rustc::util::bug::opt_span_bug_fmt
  19: rustc::util::bug::span_bug_fmt
  20: rustc_typeck::check::FnCtxt::local_ty::{{closure}}
  21: rustc_typeck::check::FnCtxt::local_ty
  22: rustc_typeck::check::FnCtxt::instantiate_value_path
  23: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  24: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  25: rustc_typeck::check::FnCtxt::check_stmt
  26: rustc_typeck::check::FnCtxt::check_block_with_expected
  27: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  28: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  29: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  30: rustc_typeck::check::check_fn
  31: rustc::ty::context::GlobalCtxt::enter_local
  32: rustc_typeck::check::typeck_tables_of
  33: rustc::ty::query::__query_compute::typeck_tables_of
  34: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  35: rustc::dep_graph::graph::DepGraph::with_task_impl
  36: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  37: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  38: rustc_typeck::check::typeck_item_bodies
  39: rustc::ty::query::__query_compute::typeck_item_bodies
  40: rustc::dep_graph::graph::DepGraph::with_task_impl
  41: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  42: rustc_typeck::check_crate
  43: rustc_interface::passes::analysis
  44: rustc::ty::query::__query_compute::analysis
  45: rustc::dep_graph::graph::DepGraph::with_task_impl
  46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  47: rustc::ty::context::tls::enter_global
  48: rustc_interface::interface::run_compiler_in_existing_thread_pool
  49: scoped_tls::ScopedKey<T>::set
  50: syntax::attr::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.43.0-nightly (fc23a8183 2020-02-11) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type bin

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

query stack during panic:
#0 [typeck_tables_of] processing `main`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors

error: could not compile `playground`.

To learn more, run the command again with --verbose.

[jonas-schievink]

Nominating due to impending stabilization, even though stable doesn't ICE yet

[Centril]

Simplified:

fn main() {
    let [.., b @ ..] = [1, 2];
    b;
}