Closed
Description
Rustc panics with the following message when trying to compile this:
error: internal compiler error: librustc_mir/transform/generator.rs:495: Broken MIR: generator contains type std::cell::Ref<u32> in MIR, but typeck only knows about for<'r, 's, 't0> {&'r std::cell::RefCell<u32>, &'s std::cell::Ref<'t0, u32>, u32, ()}
#![feature(generators, generator_trait)]
use std::ops::Generator;
use std::cell::RefCell;
fn foo<'a>(y: &'a RefCell<u32>) -> impl Generator + 'a {
return move || {
yield *y.borrow();
return "Done";
};
}
fn main() {
let y = 10;
let y_cell = RefCell::new(y);
foo(&y_cell);
}
Backtrace:
error: internal compiler error: librustc_mir/transform/generator.rs:495: Broken MIR: generator contains type std::cell::Ref<u32> in MIR, but typeck only knows about for<'r, 's, 't0> {&'r std::cell::RefCell<u32>, &'s std::cell::Ref<'t0, u32>, u32, ()}
--> src/main.rs:6:12
|
6 | return move || {
| ____________^
7 | | yield *y.borrow();
8 | | return "Done";
9 | | };
| |_____^
thread 'main' panicked at 'Box<Any>', librustc_errors/lib.rs:499:9
stack backtrace:
0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
1: std::sys_common::backtrace::print
2: std::panicking::default_hook::{{closure}}
3: std::panicking::default_hook
4: rustc::util::common::panic_hook
5: std::panicking::rust_panic_with_hook
6: std::panicking::begin_panic
7: rustc_errors::Handler::span_bug
8: rustc::session::opt_span_bug_fmt::{{closure}}
9: rustc::ty::context::tls::with_opt::{{closure}}
10: rustc::ty::context::tls::with_context_opt
11: rustc::ty::context::tls::with_opt
12: rustc::session::opt_span_bug_fmt
13: rustc::session::span_bug_fmt
14: <rustc_mir::transform::generator::StateTransform as rustc_mir::transform::MirPass>::run_pass
15: rustc_mir::transform::optimized_mir::{{closure}}
16: rustc_mir::transform::optimized_mir
17: rustc::ty::query::__query_compute::optimized_mir
18: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::optimized_mir<'tcx>>::compute
19: rustc::ty::context::tls::with_context
20: rustc::dep_graph::graph::DepGraph::with_task_impl
21: rustc::ty::context::tls::with_related_context
22: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
23: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_query
24: rustc::ty::query::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::optimized_mir
25: rustc_mir::shim::make_shim
26: rustc::ty::query::__query_compute::mir_shims
27: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::mir_shims<'tcx>>::compute
28: rustc::ty::context::tls::with_context
29: rustc::dep_graph::graph::DepGraph::with_task_impl
30: rustc::ty::context::tls::with_related_context
31: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
32: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
33: rustc::ty::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::instance_mir
34: rustc_mir::monomorphize::collector::collect_items_rec
35: rustc_mir::monomorphize::collector::collect_items_rec
36: rustc_mir::monomorphize::collector::collect_crate_mono_items::{{closure}}
37: rustc::util::common::time
38: rustc_mir::monomorphize::collector::collect_crate_mono_items
39: rustc::util::common::time
40: rustc_codegen_llvm::base::collect_and_partition_mono_items
41: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::collect_and_partition_mono_items<'tcx>>::compute
42: rustc::ty::context::tls::with_context
43: rustc::dep_graph::graph::DepGraph::with_task_impl
44: rustc::ty::context::tls::with_related_context
45: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
47: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
48: rustc::util::common::time
49: rustc_driver::driver::phase_4_codegen
50: rustc_driver::driver::compile_input::{{closure}}
51: rustc::ty::context::tls::enter_context
52: <std::thread::local::LocalKey<T>>::with
53: rustc::ty::context::TyCtxt::create_and_enter
54: rustc_driver::driver::compile_input
55: rustc_driver::run_compiler_with_pool
56: <scoped_tls::ScopedKey<T>>::set
57: <scoped_tls::ScopedKey<T>>::set
58: syntax::with_globals
59: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
60: __rust_maybe_catch_panic
61: rustc_driver::run
62: rustc_driver::main
63: std::rt::lang_start::{{closure}}
64: std::panicking::try::do_call
65: __rust_maybe_catch_panic
66: std::rt::lang_start_internal
67: main
query stack during panic:
#0 [optimized_mir] processing `foo::{{closure}}`
#1 [mir_shims] generating MIR shim for `std::ptr::drop_in_place`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
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 1.29.0-nightly (254f8796b 2018-07-13) running on x86_64-apple-darwin
note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin
Version:
rustc 1.29.0-nightly (254f8796b 2018-07-13)
binary: rustc
commit-hash: 254f8796b729810846e2b97620032ecaf103db33
commit-date: 2018-07-13
host: x86_64-apple-darwin
release: 1.29.0-nightly
LLVM version: 7.0