ICE: instantiated twice

[hellow554]

While minimizing #63263 I stumbled upon another ICE

#![feature(type_alias_impl_trait)]

type Closure = impl FnOnce();

fn c() -> Closure {
    || -> Closure { || () }
}

fn main() {}

(Playground)

Errors:

   Compiling playground v0.0.1 (/playground)
thread 'rustc' panicked at 'instantiated twice: DefId(0:12 ~ playground[1d12]::Closure[0])/OpaqueTypeDecl { substs: [], definition_span: src/main.rs:6:11: 6:18, concrete_ty: _, has_required_region_bounds: false, origin: TypeAlias }', src/librustc_typeck/check/mod.rs:2506:13
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:47
   3: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:36
   4: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:200
   5: std::panicking::default_hook
             at src/libstd/panicking.rs:214
   6: rustc::util::common::panic_hook
   7: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:481
   8: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:384
   9: std::panicking::begin_panic_fmt
             at src/libstd/panicking.rs:339
  10: rustc_typeck::check::FnCtxt::instantiate_opaque_types_from_value
  11: rustc_typeck::check::check_fn
  12: rustc_typeck::check::closure::<impl rustc_typeck::check::FnCtxt>::check_expr_closure
  13: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  14: rustc_typeck::check::FnCtxt::check_block_with_expected
  15: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  16: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  17: rustc_typeck::check::check_fn
  18: rustc::ty::context::GlobalCtxt::enter_local
  19: rustc_typeck::check::typeck_tables_of
  20: rustc::ty::query::__query_compute::typeck_tables_of
  21: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  22: rustc::dep_graph::graph::DepGraph::with_task_impl
  23: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  24: rustc_typeck::collect::find_opaque_ty_constraints::ConstraintLocator::check
  25: rustc::hir::intravisit::Visitor::visit_nested_item
  26: rustc_typeck::collect::find_opaque_ty_constraints
  27: rustc_typeck::collect::checked_type_of
  28: rustc_typeck::collect::type_of
  29: rustc::ty::query::__query_compute::type_of
  30: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::type_of>::compute
  31: rustc::dep_graph::graph::DepGraph::with_task_impl
  32: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  33: <rustc_typeck::collect::CollectItemTypesVisitor as rustc::hir::intravisit::Visitor>::visit_item
  34: rustc::hir::map::Map::visit_item_likes_in_module
  35: rustc_typeck::collect::collect_mod_item_types
  36: rustc::ty::query::__query_compute::collect_mod_item_types
  37: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::collect_mod_item_types>::compute
  38: rustc::dep_graph::graph::DepGraph::with_task_impl
  39: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  40: rustc_typeck::check_crate::{{closure}}::{{closure}}
  41: rustc::util::common::time
  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_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  48: rustc_interface::passes::create_global_ctxt::{{closure}}
  49: rustc_interface::interface::run_compiler_in_existing_thread_pool
  50: std::thread::local::LocalKey<T>::with
  51: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
query stack during panic:
#0 [typeck_tables_of] processing `c`
#1 [type_of] processing `Closure`
#2 [collect_mod_item_types] collecting item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack

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/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.38.0-nightly (d3f8a0b5d 2019-08-04) running on x86_64-unknown-linux-gnu

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

[hellow554]

@rustbot modify labels: I-ICE A-closures A-impl-trait C-bug F-type_alias_impl_trait T-compiler

[JohnTitor]

The ICE doesn't appear on the latest nightly