Closed
Description
I don’t know how related this is to #55265, the assertion is different.
struct VTable<DST: ?Sized> {
_to_dst_ptr: fn(*mut ()) -> *mut DST,
}
trait HasVTableFor<DST: ?Sized + 'static> {
const VTABLE: &'static VTable<DST>;
}
impl<T, DST: ?Sized + 'static> HasVTableFor<DST> for T {
const VTABLE: &'static VTable<DST> = &VTable {
_to_dst_ptr: |_: *mut ()| unsafe { std::mem::zeroed() },
};
}
pub fn push<DST: ?Sized + 'static, T>() {
<T as HasVTableFor<DST>>::VTABLE;
}Errors:
thread 'main' panicked at 'assertion failed: !value.needs_subst()', librustc/traits/query/normalize_erasing_regions.rs:69:9
stack backtrace:
0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
1: std::sys_common::backtrace::print
at libstd/sys_common/backtrace.rs:71
at libstd/sys_common/backtrace.rs:59
2: std::panicking::default_hook::{{closure}}
at libstd/panicking.rs:211
3: std::panicking::default_hook
at libstd/panicking.rs:227
4: rustc::util::common::panic_hook
5: std::panicking::rust_panic_with_hook
at libstd/panicking.rs:480
6: std::panicking::begin_panic
7: rustc::traits::query::normalize_erasing_regions::<impl rustc::ty::context::TyCtxt<'cx, 'tcx, 'tcx>>::normalize_erasing_late_bound_regions
8: rustc::ty::instance::Instance::resolve_closure
9: rustc_mir::interpret::cast::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::cast
10: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::run
11: rustc_mir::const_eval::eval_body_using_ecx
12: rustc_mir::const_eval::const_eval_provider
13: rustc::ty::query::__query_compute::const_eval
14: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::const_eval<'tcx>>::compute
15: rustc::dep_graph::graph::DepGraph::with_task_impl
16: rustc::ty::context::tls::with_related_context
17: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
18: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
19: rustc::ty::query::TyCtxtAt::const_eval
20: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::global_to_op
21: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::const_value_to_op
22: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::const_to_op
23: rustc_mir::transform::const_prop::ConstPropagator::eval_constant
24: rustc_mir::transform::const_prop::ConstPropagator::const_prop
25: <rustc_mir::transform::const_prop::ConstPropagator<'b, 'a, 'tcx> as rustc::mir::visit::Visitor<'tcx>>::visit_statement
26: <rustc_mir::transform::const_prop::ConstProp as rustc_mir::transform::MirPass>::run_pass
27: rustc_mir::transform::optimized_mir::{{closure}}
28: rustc_mir::transform::optimized_mir
29: rustc::ty::query::__query_compute::optimized_mir
30: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::optimized_mir<'tcx>>::compute
31: rustc::dep_graph::graph::DepGraph::with_task_impl
32: rustc::ty::context::tls::with_related_context
33: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
34: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_query
35: rustc::ty::query::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::optimized_mir
36: rustc_metadata::encoder::<impl rustc_metadata::isolated_encoder::IsolatedEncoder<'a, 'b, 'tcx>>::encode_optimized_mir
37: rustc_metadata::encoder::<impl rustc_metadata::isolated_encoder::IsolatedEncoder<'a, 'b, 'tcx>>::encode_info_for_item
38: rustc::ty::context::tls::with_context
39: <rustc_metadata::encoder::EncodeVisitor<'a, 'b, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
40: rustc::hir::Crate::visit_all_item_likes
41: rustc_metadata::encoder::encode_metadata
42: rustc_metadata::cstore_impl::<impl rustc::middle::cstore::CrateStore for rustc_metadata::cstore::CStore>::encode_metadata
43: rustc::ty::context::TyCtxt::encode_metadata
44: rustc_codegen_llvm::base::write_metadata
45: rustc::util::common::time
46: rustc_codegen_llvm::base::codegen_crate
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: rustc_driver::driver::spawn_thread_pool
57: rustc_driver::run_compiler
58: <scoped_tls::ScopedKey<T>>::set
59: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
60: __rust_maybe_catch_panic
at libpanic_unwind/lib.rs:102
61: rustc_driver::run
62: rustc_driver::main
63: std::rt::lang_start::{{closure}}
64: std::panicking::try::do_call
at libstd/rt.rs:59
at libstd/panicking.rs:310
65: __rust_maybe_catch_panic
at libpanic_unwind/lib.rs:102
66: std::rt::lang_start_internal
at libstd/panicking.rs:289
at libstd/panic.rs:392
at libstd/rt.rs:58
67: main
68: __libc_start_main
69: <unknown>
query stack during panic:
#0 [const_eval] const-evaluating `<T as HasVTableFor<DST>>::VTABLE`
--> src/lib.rs:16:5
|
16 | <T as HasVTableFor<DST>>::VTABLE;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#1 [optimized_mir] processing `push`
end of query stack
error: internal compiler error: unexpected panic
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 1.31.0-nightly (424a749a0 2018-10-21) running on x86_64-unknown-linux-gnu
note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `playground`.