ICE: Error encountered resolving bounds after type-checking #73229
Description
Code
fn any<T>() -> T { loop {} } trait Foo { type V; } trait Callback<T: Foo>: Fn(&T, &T::V) {} impl<T: Foo, F: Fn(&T, &T::V)> Callback<T> for F {} struct Bar<T: Foo> { callback: Box<dyn Callback<T>>, } impl<T: Foo> Bar<T> { fn event(&self) { (self.callback)(any(), any()); } } struct A; struct B; impl Foo for A { type V = B; } fn main() { let foo = Bar::<A> { callback: Box::new(|_: &A, _: &B| ()), }; foo.event(); }Meta
rustc --version --verbose:
rustc 1.46.0-nightly (feb3536eb 2020-06-09) binary: rustc commit-hash: feb3536eba10c2e4585d066629598f03d5ddc7c6 commit-date: 2020-06-09 host: x86_64-unknown-linux-gnu release: 1.46.0-nightly LLVM version: 10.0 Error output
error: internal compiler error: src/librustc_trait_selection/traits/codegen/mod.rs:108: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<dyn for<'r, 's> Callback<A, Output = ()> as std::ops::Fn<(&A, &B)>>)), depth=1),Unimplemented)]` resolving bounds after type-checking Backtrace
thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:907:9 stack backtrace: 0: backtrace::backtrace::libunwind::trace at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86 1: backtrace::backtrace::trace_unsynchronized at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66 2: std::sys_common::backtrace::_print_fmt at src/libstd/sys_common/backtrace.rs:78 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:1076 5: std::io::Write::write_fmt at src/libstd/io/mod.rs:1537 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:198 9: std::panicking::default_hook at src/libstd/panicking.rs:218 10: rustc_driver::report_ice 11: std::panicking::rust_panic_with_hook at src/libstd/panicking.rs:481 12: std::panicking::begin_panic 13: rustc_errors::HandlerInner::bug 14: rustc_errors::Handler::bug 15: rustc_middle::util::bug::opt_span_bug_fmt::{{closure}} 16: rustc_middle::ty::context::tls::with_opt::{{closure}} 17: rustc_middle::ty::context::tls::with_opt 18: rustc_middle::util::bug::opt_span_bug_fmt 19: rustc_middle::util::bug::bug_fmt 20: rustc_trait_selection::traits::codegen::drain_fulfillment_cx_or_panic 21: rustc_middle::ty::context::GlobalCtxt::enter_local 22: rustc_trait_selection::traits::codegen::codegen_fulfill_obligation 23: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::codegen_fulfill_obligation>::compute 24: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl 25: rustc_data_structures::stack::ensure_sufficient_stack 26: rustc_query_system::query::plumbing::get_query_impl 27: rustc_ty::instance::resolve_instance 28: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::resolve_instance>::compute 29: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl 30: rustc_data_structures::stack::ensure_sufficient_stack 31: rustc_query_system::query::plumbing::get_query_impl 32: rustc_middle::ty::instance::Instance::resolve 33: <rustc_mir::monomorphize::collector::MirNeighborCollector as rustc_middle::mir::visit::Visitor>::visit_terminator_kind 34: rustc_mir::monomorphize::collector::collect_neighbours 35: rustc_data_structures::stack::ensure_sufficient_stack 36: rustc_mir::monomorphize::collector::collect_items_rec 37: rustc_mir::monomorphize::collector::collect_items_rec 38: rustc_mir::monomorphize::collector::collect_crate_mono_items 39: rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items 40: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::collect_and_partition_mono_items>::compute 41: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl 42: rustc_query_system::query::plumbing::get_query_impl 43: rustc_codegen_ssa::base::codegen_crate 44: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate 45: rustc_interface::passes::start_codegen 46: rustc_middle::ty::context::tls::enter_global 47: rustc_interface::queries::Queries::ongoing_codegen 48: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter 49: rustc_span::with_source_map 50: rustc_interface::interface::run_compiler_in_existing_thread_pool 51: scoped_tls::ScopedKey<T>::set