error: internal compiler error: /checkout/src/librustc_typeck/check/mod.rs:626: escaping regions in predicate ...

[tmzt]

I tried this code:

        fn resolve_props<I>(&mut self, props: I) -> impl IntoIterator<Item = PropValue>
          where I: IntoIterator<Item = Prop>

(see https://github.com/tmzt/isymtope/blob/compiler-bug-impl-intoiterator/src/processing/process_comp_def.rs#L123)

When I run the following command:

cargo test -- test_process_comp_def1

I expected to see this happen: It should compile the test correctly

Instead, this happened:

error: internal compiler error: /checkout/src/librustc_typeck/check/mod.rs:626: escaping regions in predicate Obligation(predicate=Binder(ProjectionPredicate(ProjectionTy { substs: Slice([_]), item_def_id: DefId { krate: CrateNum(2), node: DefIndex(1755) => core/7405dbf::iter[0]::traits[0]::IntoIterator[0]::Item[0] } }, (&str, std::option::Option<&parser::ast::ExprValue>))),depth=0)
   --> src/processing/process_comp_def.rs:123:53
    |
123 |         fn resolve_props<I>(&mut self, props: I) -> impl IntoIterator<Item = PropValue>
    |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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 1.21.0-nightly (59ccba995 2017-08-17) running on x86_64-unknown-linux-gnu

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:434:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.

error: Could not compile `isymtope`.

Meta

rustc --version --verbose:

rustc 1.21.0-nightly (59ccba995 2017-08-17)
binary: rustc
commit-hash: 59ccba995de202fb9d9a8d795d2770fb2d199db0
commit-date: 2017-08-17
host: x86_64-unknown-linux-gnu
release: 1.21.0-nightly
LLVM version: 4.0

Backtrace:

(NOTE: omitted unrelated warnings)

error: internal compiler error: /checkout/src/librustc_typeck/check/mod.rs:626: escaping regions in predicate Obligation(predicate=Binder(ProjectionPredicate(ProjectionTy { substs: Slice([_]), item_def_id: DefId { krate: CrateNum(2), node: DefIndex(1755) => core/7405dbf::iter[0]::traits[0]::IntoIterator[0]::Item[0] } }, (&str, std::option::Option<&parser::ast::ExprValue>))),depth=0)
   --> src/processing/process_comp_def.rs:123:53
    |
123 |         fn resolve_props<I>(&mut self, props: I) -> impl IntoIterator<Item = PropValue>
    |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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 1.21.0-nightly (59ccba995 2017-08-17) running on x86_64-unknown-linux-gnu

note: run with `RUST_BACKTRACE=1` for a backtrace

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:434:8
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
             at /checkout/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::_print
             at /checkout/src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at /checkout/src/libstd/sys_common/backtrace.rs:60
             at /checkout/src/libstd/panicking.rs:381
   3: std::panicking::default_hook
             at /checkout/src/libstd/panicking.rs:391
   4: std::panicking::rust_panic_with_hook
             at /checkout/src/libstd/panicking.rs:611
   5: std::panicking::begin_panic
   6: rustc_errors::Handler::span_bug
   7: rustc::session::opt_span_bug_fmt::{{closure}}
   8: rustc::session::span_bug_fmt
   9: rustc_typeck::check::Inherited::register_predicate
  10: <rustc::ty::fold::BottomUpFolder<'a, 'gcx, 'tcx, F> as rustc::ty::fold::TypeFolder<'gcx, 'tcx>>::fold_ty
  11: rustc_typeck::check::check_fn
  12: rustc_typeck::check::typeck_tables_of::{{closure}}
  13: rustc_typeck::check::typeck_tables_of
  14: rustc::dep_graph::graph::DepGraph::with_task
  15: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables_of<'tcx>>::try_get
  16: rustc::ty::maps::TyCtxtAt::typeck_tables_of
  17: rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::typeck_tables_of
  18: rustc_typeck::check::typeck_item_bodies
  19: rustc::dep_graph::graph::DepGraph::with_task
  20: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_item_bodies<'tcx>>::try_get
  21: rustc::ty::maps::TyCtxtAt::typeck_item_bodies
  22: rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::typeck_item_bodies
  23: rustc_typeck::check_crate
  24: rustc::ty::context::TyCtxt::create_and_enter
  25: rustc_driver::driver::compile_input
  26: rustc_driver::run_compiler

error: Could not compile `isymtope`.

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

[kennytm]

Duplicate of #42479

[Mark-Simulacrum]

Closing as a duplicate of #42479.