ICE on stable and nightly: compiler/rustc_trait_selection/src/traits/select/mod.rs:2013:17

[dnavre]

Code

I'm a complete Rust newbie and most of the time I have no idea of what I'm doing. So my source code is probably completely weird and f*cked up by the standards of a seasoned Rust developer. Still, I don't think my compiler should be panicking :) Also please note that the source code is definitely not even supposed to compile, it DOES have a number of syntax errors, however, I would expect a reasonable error message explaining what I'm doing wrong.
The whole project can be found here: XXX
Big thanks to @fee1-dead who has minimized the code to a very simple test case that crashes the compiler: #91594 (comment)

I also found several similar bugs reported but I'm still not sure if this is a duplicate or not. Similar bug reports:
#55765
#25036

To reproduce:

cargo build

Meta

The bug does exist in the current nightly build.

rustc --version --verbose:

rustc 1.57.0 (f1edd0429 2021-11-29)
binary: rustc
commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
commit-date: 2021-11-29
host: x86_64-apple-darwin
release: 1.57.0
LLVM version: 13.0.0

Error output

error: internal compiler error: compiler/rustc_trait_selection/src/traits/select/mod.rs:2072:17: Impl DefId(0:335 ~ map_server[3b29]::mapserver::endpoints::map_endpoint::{impl#2}) was matchable against Obligation(predicate=Binder(TraitPredicate(<mapserver::endpoints::map_endpoint::map_endpoint as shaku::HasComponent<(dyn mapserver::environment::map::Map + 'static)>>, polarity:Positive), []), depth=3) but now is not

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1170:9

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 1.59.0-nightly (e2116acae 2021-12-05) running on x86_64-apple-darwin

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

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

query stack during panic:
#0 [evaluate_obligation] evaluating trait selection obligation `mapserver::endpoints::map_endpoint::map_endpoint: shaku::module::module_traits::ModuleInterface`  |  = note: this failure-note originates in the macro `module` (in Nightly builds, run with -Z macro-backtrace for more info)

#1 [check_item_well_formed] checking that `mapserver::endpoints::map_endpoint::<impl at src/mapserver/endpoints/map_endpoint.rs:8:1: 13:2>` is well-formed
end of query stack
warning: `map-server` (bin "map-server") generated 5 warnings
error: could not compile `map-server`; 5 warnings emitted

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1146:9
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::util::bug::opt_span_bug_fmt::{{closure}}
   5: rustc_middle::ty::context::tls::with_opt::{{closure}}
   6: rustc_middle::ty::context::tls::with_opt
   7: rustc_middle::util::bug::opt_span_bug_fmt
   8: rustc_middle::util::bug::bug_fmt
   9: rustc_infer::infer::InferCtxt::commit_unconditionally
  10: rustc_trait_selection::traits::select::confirmation::<impl rustc_trait_selection::traits::select::SelectionContext>::confirm_candidate
  11: rustc_infer::infer::InferCtxt::probe
  12: rustc_trait_selection::traits::select::SelectionContext::evaluate_stack
  13: rustc_query_system::dep_graph::graph::DepGraph<K>::with_anon_task
  14: rustc_trait_selection::traits::select::SelectionContext::evaluate_trait_predicate_recursively
  15: rustc_data_structures::stack::ensure_sufficient_stack
  16: rustc_trait_selection::traits::select::SelectionContext::evaluate_predicate_recursively
  17: rustc_trait_selection::traits::select::SelectionContext::evaluate_predicates_recursively
  18: rustc_infer::infer::InferCtxt::probe
  19: rustc_trait_selection::traits::select::SelectionContext::evaluate_stack
  20: rustc_query_system::dep_graph::graph::DepGraph<K>::with_anon_task
  21: rustc_trait_selection::traits::select::SelectionContext::evaluate_trait_predicate_recursively
  22: rustc_data_structures::stack::ensure_sufficient_stack
  23: rustc_trait_selection::traits::select::SelectionContext::evaluate_predicate_recursively
  24: rustc_trait_selection::traits::select::SelectionContext::evaluate_predicates_recursively
  25: rustc_infer::infer::InferCtxt::probe
  26: rustc_trait_selection::traits::select::SelectionContext::evaluate_stack
  27: rustc_query_system::dep_graph::graph::DepGraph<K>::with_anon_task
  28: rustc_trait_selection::traits::select::SelectionContext::evaluate_trait_predicate_recursively
  29: rustc_data_structures::stack::ensure_sufficient_stack
  30: rustc_trait_selection::traits::select::SelectionContext::evaluate_predicate_recursively
  31: rustc_infer::infer::InferCtxt::probe
  32: rustc_trait_selection::traits::select::SelectionContext::evaluate_root_obligation
  33: rustc_infer::infer::InferCtxtBuilder::enter_with_canonical
  34: rustc_traits::evaluate_obligation::evaluate_obligation
  35: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  36: rustc_data_structures::stack::ensure_sufficient_stack
  37: rustc_query_system::query::plumbing::try_execute_query
  38: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::evaluate_obligation
  39: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation
  40: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation_no_overflow
  41: rustc_trait_selection::traits::fulfill::FulfillProcessor::process_trait_obligation
  42: rustc_trait_selection::traits::fulfill::FulfillProcessor::progress_changed_obligations
  43: rustc_data_structures::obligation_forest::ObligationForest<O>::process_obligations
  44: rustc_trait_selection::traits::fulfill::FulfillmentContext::select
  45: <rustc_trait_selection::traits::fulfill::FulfillmentContext as rustc_infer::traits::engine::TraitEngine>::select_with_constness_where_possible
  46: <rustc_trait_selection::traits::fulfill::FulfillmentContext as rustc_infer::traits::engine::TraitEngine>::select_all_with_constness_or_error
  47: rustc_typeck::check::fn_ctxt::_impl::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::select_all_obligations_or_error
  48: rustc_infer::infer::InferCtxtBuilder::enter
  49: rustc_typeck::check::wfcheck::check_item_well_formed
  50: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  51: rustc_data_structures::stack::ensure_sufficient_stack
  52: rustc_query_system::query::plumbing::try_execute_query
  53: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  54: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  55: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  56: rustc_data_structures::sync::par_for_each_in
  57: rustc_session::session::Session::track_errors
  58: rustc_typeck::check_crate
  59: rustc_interface::passes::analysis
  60: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  61: rustc_data_structures::stack::ensure_sufficient_stack
  62: rustc_query_system::query::plumbing::try_execute_query
  63: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  64: rustc_interface::passes::QueryContext::enter
  65: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  66: rustc_span::with_source_map
  67: scoped_tls::ScopedKey<T>::set
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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.57.0 (f1edd0429 2021-11-29) running on x86_64-apple-darwin

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

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

query stack during panic:
#0 [evaluate_obligation] evaluating trait selection obligation `mapserver::endpoints::map_endpoint::map_endpoint: shaku::module::module_traits::ModuleInterface`  |  = note: this failure-note originates in the macro `module` (in Nightly builds, run with -Z macro-backtrace for more info)

#1 [check_item_well_formed] checking that `mapserver::endpoints::map_endpoint::<impl at src/mapserver/endpoints/map_endpoint.rs:8:1: 13:2>` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
warning: `map-server` (bin "map-server") generated 5 warnings
error: could not compile `map-server`; 5 warnings emitted

[fee1-dead]

Minimized: (play)

trait Component<M> {
    type Interface;
}
trait HasComponent<I> {}

struct Foo;

impl HasComponent<<Foo as Component<Foo>>::Interface> for Foo {}

impl<M: HasComponent<()>> Component<M> for Foo {
    type Interface = u8;
}

Note: I used perses for reducing most of the unneeded code, and cargo-expand to put everything in one big file.

[dnavre]

@fee1-dead Thanks for doing that, I'll edit my original post to link to your reply to see a code example.

P.S.
I did open the code reduction tools you linked, but I still am not sure how you got to this minimized state, great job :D

[JohnTitor]

Triage: It now returns some compiler errors and is no longer ICE, fixed by #91844, I guess. Marking as E-needs-test.

[JohnTitor]

@dnavre Just in case, if you could check your code with the latest nightly, it'd be great.

[dnavre]

@JohnTitor Indeed, tested with the latest nightly this produces various compiler errors and no ICE. Thank you!