Closed
Description
possibly related to #60070, #52812, and #29997
pub trait Trait<'a> {
type Item;
}
impl<'a> Trait<'a> for () {
type Item= ();
}
pub fn foo<T, F>(_: T, _: F)
where T: for<'a> Trait<'a>,
F: for<'a> FnMut(<T as Trait<'a>>::Item) {}
fn main() {
foo((), drop)
}stack trace
error: internal compiler error: src\librustc\traits\project.rs:1457: Failed to unify obligation `Obligation(predicate=ProjectionTy { substs: [fn(_) {std::mem::drop::<_>}, (<() as Trait<'a>>::Item,)], item_def_id: DefId(2/0:1000 ~ core[d10a]::ops[0]::function[0]::FnOnce[0]::Output[0]) },depth=0)` with poly_projection `Binder(ProjectionPredicate(ProjectionTy { substs: [fn(_) {std::mem::drop::<_>}, ((),)], item_def_id:DefId(2/0:1000 ~ core[d10a]::ops[0]::function[0]::FnOnce[0]::Output[0]) }, ()))`: Sorts(ExpectedFound { expected: (), found: <() as Trait<'a>>::Item })
--> src\main.rs:14:5
|
14 | foo((), drop)
| ^^^
thread 'rustc' panicked at 'Box<Any>', src\librustc_errors\lib.rs:570:9
stack backtrace:
0: std::sys_common::alloc::realloc_fallback
1: std::panicking::take_hook
2: std::panicking::take_hook
3: rustc::ty::structural_impls::<impl rustc::ty::context::Lift for rustc::ty::adjustment::AutoBorrow>::lift_to_tcx
4: std::panicking::rust_panic_with_hook
5: <rustc::ty::CrateInherentImpls as core::fmt::Debug>::fmt
6: rustc::ty::structural_impls::<impl rustc::ty::context::Lift for rustc::mir::interpret::GlobalId>::lift_to_tcx
7: rustc::util::bug::bug_fmt
8: rustc::ty::trait_def::TraitDef::ancestors
9: rustc::ty::trait_def::TraitDef::ancestors
10: rustc::ty::trait_def::TraitDef::ancestors
11: rustc::util::bug::bug_fmt
12: rustc::util::bug::bug_fmt
13: rustc::traits::project::normalize_projection_type
14: rustc::traits::project::normalize_projection_type
15: rustc::traits::project::normalize_projection_type
16: rustc::traits::project::poly_project_and_unify_type
17: rustc::infer::InferCtxt::commit_from
18: rustc::ty::structural_impls::<impl rustc::ty::context::Lift for rustc::mir::interpret::GlobalId>::lift_to_tcx
19: <rustc::traits::fulfill::FulfillmentContext as rustc::traits::engine::TraitEngine>::select_where_possible
20: rustc_typeck::check::FnCtxt::field_ty
21: rustc_typeck::check::FnCtxt::self_type_matches_expected_vid
22: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call
23: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call
24: rustc_typeck::check::FnCtxt::check_struct_path
25: rustc_typeck::check::FnCtxt::check_struct_path
26: rustc_typeck::check::FnCtxt::check_block_no_value
27: rustc_typeck::check::FnCtxt::check_struct_path
28: rustc_typeck::check::FnCtxt::check_struct_path
29: rustc_typeck::check::FnCtxt::impl_self_ty
30: <rustc_typeck::check::GatherLocalsVisitor as rustc::hir::intravisit::Visitor>::visit_pat
31: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
32: <rustc_typeck::check::CheckItemTypesVisitor as rustc::hir::itemlikevisit::ItemLikeVisitor>::visit_item
33: <rustc_typeck::variance::constraints::ConstraintContext as rustc::hir::itemlikevisit::ItemLikeVisitor>::visit_impl_item
34: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
35: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
36: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
37: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
38: <rustc_typeck::check::CheckItemTypesVisitor as rustc::hir::itemlikevisit::ItemLikeVisitor>::visit_item
39: <rustc_typeck::variance::constraints::ConstraintContext as rustc::hir::itemlikevisit::ItemLikeVisitor>::visit_impl_item
40: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
41: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
42: <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt
43: rustc_typeck::check_crate
44: rustc_interface::passes::BoxedResolver::to_expansion_result
45: rustc_driver::set_sigpipe_handler
46: <env_logger::filter::inner::Filter as core::fmt::Display>::fmt
47: <env_logger::fmt::WriteStyle as core::default::Default>::default
48: <env_logger::filter::inner::Filter as core::fmt::Display>::fmt
49: rustc_driver::set_sigpipe_handler
50: rustc_driver::set_sigpipe_handler
51: rustc_interface::interface::Compiler::output_file
52: rustc_driver::set_sigpipe_handler
53: <env_logger::fmt::WriteStyle as core::default::Default>::default
54: rustc_driver::set_sigpipe_handler
55: <env_logger::filter::inner::Filter as core::fmt::Display>::fmt
56: <rustc_driver::pretty::UserIdentifiedItem as core::fmt::Debug>::fmt
57: rustc_driver::set_sigpipe_handler
58: _rust_maybe_catch_panic
59: rustc_driver::set_sigpipe_handler
60: <std::error::<impl core::convert::From<alloc::string::String> for alloc::boxed::Box<dyn +std::error::Error+core::marker::Send+core::marker::Sync>>::from::StringError as core::fmt::Display>::fmt
61: std::sys::windows::thread::Thread::new
62: BaseThreadInitThunk
63: RtlUserThreadStart
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 previous error
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 1.35.0-nightly (70f130954 2019-04-16) running on x86_64-pc-windows-msvc
note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin
note: some of the compiler flags provided by cargo are hidden