ICE unexpected type in type_metadata: impl core::future::future::Future

[PvdBerg1998]

Latest nightly (x86_64-pc-windows-msvc) panics when I run cargo test on my codebase using async await.

error: internal compiler error: src\librustc_codegen_llvm\debuginfo\metadata.rs:661: debuginfo: unexpected type in type_metadata: impl core::future::future::Future

thread 'rustc' panicked at 'Box<Any>', src\librustc_errors\lib.rs:620:9

[PvdBerg1998]

stack backtrace:
   0: std::sys_common::alloc::realloc_fallback
   1: std::panicking::take_hook
   2: std::panicking::take_hook
   3: <rustc::ty::sty::Binder<rustc::ty::ProjectionPredicate<'tcx>> as rustc::ty::ToPredicate<'tcx>>::to_predicate
   4: std::panicking::rust_panic_with_hook
   5: <rustc_errors::emitter::ColorConfig as core::fmt::Debug>::fmt
   6: rustc_errors::Handler::bug
   7: rustc::util::bug::bug_fmt
   8: rustc::ty::context::<impl rustc::infer::canonical::Canonical<'gcx, rustc::ty::context::UserType<'gcx>>>::is_identity
   9: rustc::ty::context::<impl rustc::infer::canonical::Canonical<'gcx, rustc::ty::context::UserType<'gcx>>>::is_identity
  10: rustc::ty::context::<impl rustc::infer::canonical::Canonical<'gcx, rustc::ty::context::UserType<'gcx>>>::is_identity
  11: rustc::util::bug::bug_fmt
  12: rustc::util::bug::bug_fmt
  13: <rustc_codegen_llvm::back::wasm::WasmSections<'a> as core::iter::traits::iterator::Iterator>::next
  14: rustc_codegen_llvm::debuginfo::<impl rustc_codegen_ssa::traits::debuginfo::DebugInfoBuilderMethods<'tcx> for rustc_codegen_llvm::builder::Builder<'a, 'll, 'tcx>>::declare_local
  15: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::join_codegen_and_link
  16: <rustc_codegen_llvm::llvm_::ffi::debuginfo::DISPFlags as core::fmt::Debug>::fmt
  17: <unknown>
  18: rustc_codegen_llvm::llvm_::diagnostic::Diagnostic::unpack
  19: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::join_codegen_and_link
  20: <rustc_codegen_llvm::base::ValueIter<'ll> as core::iter::traits::iterator::Iterator>::next
  21: <rustc_codegen_llvm::llvm_::ffi::PassKind as core::fmt::Debug>::fmt
  22: <rustc_codegen_llvm::base::ValueIter<'ll> as core::iter::traits::iterator::Iterator>::next
  23: rustc_codegen_llvm::llvm_::diagnostic::Diagnostic::unpack
  24: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
  25: <env_logger::fmt::WriteStyle as core::default::Default>::default
  26: rustc_driver::driver::phase_4_codegen
  27: <rustc_driver::pretty::UserIdentifiedItem as core::fmt::Debug>::fmt
  28: <env_logger::Logger as log::Log>::flush
  29: rustc_driver::driver::compile_input
  30: rustc_driver::run_compiler
  31: <env_logger::Logger as log::Log>::flush
  32: rustc_driver::run_compiler
  33: <env_logger::Logger as log::Log>::flush
  34: <rustc_driver::CompilationFailure as core::fmt::Debug>::fmt
  35: _rust_maybe_catch_panic
  36: <env_logger::Logger as log::Log>::flush
  37: std::sys::windows::thread::Thread::new
  38: BaseThreadInitThunk
  39: RtlUserThreadStart
query stack during panic:
end of query stack

[jonas-schievink]

Can you post the source code, or an example that reproduces this? Is this also happening on older nightlies or did this recently appear?

[PvdBerg1998]

Only the last nightly. I have no idea what code is causing this. It does not occur when I run cargo check, only cargo run or cargo test, that may be useful to know.

[jonas-schievink]

The stacktrace also mentions WASM, are you targeting that, and does it happen with other targets too?

[PvdBerg1998]

I'm not targeting WASM. I played a bit with how much of my code I can remove until it starts compiling again. This is causing the same error: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=b1e77a15da5f42edcd4031dd6af8939f

[PvdBerg1998]

It seems this only panics when the functions are implemented as methods, so when you remove the structure it does compile.

[jonas-schievink]

Great, thanks!

(we don't seem to track nightly-to-nightly regressions anymore)

[PvdBerg1998]

The stacktrace in the minimal example is different:

stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:59
             at src/libstd/panicking.rs:200
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:215
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:482
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::bug
   8: rustc::util::bug::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::util::bug::opt_span_bug_fmt
  13: rustc::util::bug::bug_fmt
  14: rustc_codegen_llvm::debuginfo::metadata::type_metadata
  15: rustc_codegen_llvm::debuginfo::<impl rustc_codegen_ssa::traits::debuginfo::DebugInfoBuilderMethods<'tcx> for rustc_codegen_llvm::builder::Builder<'a, 'll, 'tcx>>::declare_local
  16: core::iter::traits::iterator::Iterator::fold::{{closure}}
  17: <core::iter::adapters::Map<I, F> as core::iter::traits::iterator::Iterator>::fold
  18: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T, I>>::from_iter
  19: rustc_codegen_ssa::mir::codegen_mir
  20: rustc_codegen_ssa::base::codegen_instance
  21: rustc_codegen_ssa::mono_item::MonoItemExt::define
  22: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen
  23: rustc::dep_graph::graph::DepGraph::with_task
  24: rustc_codegen_llvm::base::compile_codegen_unit
  25: rustc_codegen_ssa::base::codegen_crate
  26: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
  27: rustc::util::common::time
  28: rustc_driver::driver::phase_4_codegen
  29: <std::thread::local::LocalKey<T>>::with
  30: rustc::ty::context::TyCtxt::create_and_enter
  31: rustc_driver::driver::compile_input
  32: <scoped_tls::ScopedKey<T>>::set
  33: rustc_driver::run_compiler
  34: <scoped_tls::ScopedKey<T>>::set
  35: syntax::with_globals
  36: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:87
  37: <F as alloc::boxed::FnBox<A>>::call_box
  38: std::sys::unix::thread::Thread::new::thread_start
             at /rustc/0ea22717a1e01fa535534b85a5347a7e49fc79de/src/liballoc/boxed.rs:759
             at src/libstd/sys_common/thread.rs:14
             at src/libstd/sys/unix/thread.rs:80
  39: start_thread
  40: __clone

[dvc94ch]

Same problem on linux...