ICE with async_trait

[theunkn0wn1]

Note: This also requires a incorrectly configured Cargo.toml, one that declares but doesn't enable async_trait. The easiest way to reproduce this bug is to clone this repository: https://github.com/theunkn0wn1/Rust-ICE-0

This occurs both on stable and nightly.

Code

#![no_std]
#[cfg(test)]

use async_trait::async_trait;
use ufmt::{uWrite, uwriteln};


#[async_trait]
trait MyTraitAsync<ComError>{
    const HEADER: &'static str;

    async fn read(&mut self, cmd: VarOffset) -> Result<u16, ComError>;
    // Print one of the internal variables of the controller to a uWrite
    async fn ushow_var<W: uWrite>(&mut self, f: &mut W, var: VarOffset) -> Result<(), ComError> {
        uwriteln!(f, "{:?}: {}", var, self.read(var).await.ok().unwrap()).ok();
        Ok(())
    }
}

Meta

$ cat /etc/os-release 
NAME="Ubuntu"
VERSION="18.04.5 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.5 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

rustc --version --verbose:

$ rustc --version --verbose
rustc 1.50.0 (cb75ad5db 2021-02-10)
binary: rustc
commit-hash: cb75ad5db02783e8b0222fee363c5f63f7e2cf5b
commit-date: 2021-02-10
host: x86_64-unknown-linux-gnu
release: 1.50.0

$ rustc +nightly --version --verbose
rustc 1.52.0-nightly (3e826bb11 2021-02-21)
binary: rustc
commit-hash: 3e826bb11228508fbe749e594038d6727208aa94
commit-date: 2021-02-21
host: x86_64-unknown-linux-gnu
release: 1.52.0-nightly
LLVM version: 11.0.1

Error output

error[E0706]: functions in traits cannot be declared `async`
  --> src/lib.rs:12:5
   |
12 |     async fn read(&mut self, cmd: VarOffset) -> Result<u16, ComError>;
   |     -----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |     |
   |     `async` because of this
   |
   = note: `async` trait functions are not currently supported
   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait

error[E0706]: functions in traits cannot be declared `async`
  --> src/lib.rs:14:5
   |
14 |       async fn ushow_var<W: uWrite>(&mut self, f: &mut W, var: VarOffset) -> Result<(), ComError> {
   |       ^----
   |       |
   |  _____`async` because of this
   | |
15 | |         uwriteln!(f, "{:?}: {}", var, self.read(var).await.ok().unwrap()).ok();
16 | |         Ok(())
17 | |     }
   | |_____^
   |
   = note: `async` trait functions are not currently supported
   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait

error: cannot find attribute `async_trait` in this scope
 --> src/lib.rs:8:3
  |
8 | #[async_trait]
  |   ^^^^^^^^^^^

error[E0412]: cannot find type `VarOffset` in this scope
  --> src/lib.rs:12:35
   |
12 |     async fn read(&mut self, cmd: VarOffset) -> Result<u16, ComError>;
   |                                   ^^^^^^^^^ not found in this scope

error[E0412]: cannot find type `VarOffset` in this scope
  --> src/lib.rs:14:62
   |
14 |     async fn ushow_var<W: uWrite>(&mut self, f: &mut W, var: VarOffset) -> Result<(), ComError> {
   |                                                              ^^^^^^^^^ not found in this scope

error[E0728]: `await` is only allowed inside `async` functions and blocks
  --> src/lib.rs:15:39
   |
15 |         uwriteln!(f, "{:?}: {}", var, self.read(var).await.ok().unwrap()).ok();
   |                                       ^^^^^^^^^^^^^^^^^^^^ only allowed inside `async` functions and blocks
   |
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

Backtrace

~/projects/reproductions/ice0 on  master! ⌚ 23:48:18
$ RUST_BACKTRACE=1 cargo build
   Compiling ice0 v0.1.0 (/home/orion/projects/reproductions/ice0)
error[E0706]: functions in traits cannot be declared `async`
  --> src/lib.rs:12:5
   |
12 |     async fn read(&mut self, cmd: VarOffset) -> Result<u16, ComError>;
   |     -----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |     |
   |     `async` because of this
   |
   = note: `async` trait functions are not currently supported
   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait

error[E0706]: functions in traits cannot be declared `async`
  --> src/lib.rs:14:5
   |
14 |       async fn ushow_var<W: uWrite>(&mut self, f: &mut W, var: VarOffset) -> Result<(), ComError> {
   |       ^----
   |       |
   |  _____`async` because of this
   | |
15 | |         uwriteln!(f, "{:?}: {}", var, self.read(var).await.ok().unwrap()).ok();
16 | |         Ok(())
17 | |     }
   | |_____^
   |
   = note: `async` trait functions are not currently supported
   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait

error: cannot find attribute `async_trait` in this scope
 --> src/lib.rs:8:3
  |
8 | #[async_trait]
  |   ^^^^^^^^^^^

error[E0412]: cannot find type `VarOffset` in this scope
  --> src/lib.rs:12:35
   |
12 |     async fn read(&mut self, cmd: VarOffset) -> Result<u16, ComError>;
   |                                   ^^^^^^^^^ not found in this scope

error[E0412]: cannot find type `VarOffset` in this scope
  --> src/lib.rs:14:62
   |
14 |     async fn ushow_var<W: uWrite>(&mut self, f: &mut W, var: VarOffset) -> Result<(), ComError> {
   |                                                              ^^^^^^^^^ not found in this scope

error[E0728]: `await` is only allowed inside `async` functions and blocks
  --> src/lib.rs:15:39
   |
15 |         uwriteln!(f, "{:?}: {}", var, self.read(var).await.ok().unwrap()).ok();
   |                                       ^^^^^^^^^^^^^^^^^^^^ only allowed inside `async` functions and blocks
   |
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_middle/src/hir/map/mod.rs:178:30
stack backtrace:
   0: rust_begin_unwind
             at /rustc/cb75ad5db02783e8b0222fee363c5f63f7e2cf5b/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/cb75ad5db02783e8b0222fee363c5f63f7e2cf5b/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/cb75ad5db02783e8b0222fee363c5f63f7e2cf5b/library/core/src/panicking.rs:50:5
   3: rustc_middle::hir::map::Map::def_kind
   4: core::ops::function::FnOnce::call_once
   5: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
   6: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
   7: rustc_query_system::query::plumbing::get_query_impl
   8: rustc_middle::ty::util::<impl rustc_middle::ty::context::TyCtxt>::closure_base_def_id
   9: rustc_typeck::collect::generics_of
  10: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::generics_of>::compute
  11: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  12: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  13: rustc_data_structures::stack::ensure_sufficient_stack
  14: rustc_query_system::query::plumbing::get_query_impl
  15: rustc_query_system::query::plumbing::ensure_query_impl
  16: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  17: rustc_hir::intravisit::walk_expr
  18: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  19: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  20: rustc_hir::intravisit::walk_expr
  21: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  22: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  23: rustc_hir::intravisit::walk_expr
  24: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  25: rustc_hir::intravisit::walk_block
  26: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  27: rustc_hir::intravisit::walk_trait_item
  28: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_trait_item
  29: rustc_middle::hir::map::Map::visit_item_likes_in_module
  30: rustc_typeck::collect::collect_mod_item_types
  31: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::collect_mod_item_types>::compute
  32: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  33: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  34: rustc_data_structures::stack::ensure_sufficient_stack
  35: rustc_query_system::query::plumbing::get_query_impl
  36: rustc_query_system::query::plumbing::ensure_query_impl
  37: rustc_typeck::check_crate
  38: rustc_interface::passes::analysis
  39: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::analysis>::compute
  40: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  41: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  42: rustc_data_structures::stack::ensure_sufficient_stack
  43: rustc_query_system::query::plumbing::get_query_impl
  44: rustc_interface::passes::QueryContext::enter
  45: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  46: rustc_span::with_source_map
  47: rustc_interface::interface::create_compiler_and_run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.50.0 (cb75ad5db 2021-02-10) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [def_kind] looking up definition kind of `MyTraitAsync::ushow_var::{closure#0}`
#1 [generics_of] computing generics of `MyTraitAsync::ushow_var::{closure#0}::{closure#0}`
#2 [collect_mod_item_types] collecting item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 6 previous errors

Some errors have detailed explanations: E0412, E0706, E0728.
For more information about an error, try `rustc --explain E0412`.
error: could not compile `ice0`

To learn more, run the command again with --verbose.

[SNCPlay42]

MCVE:

trait MyTraitAsync {
    async fn async_fn() {
        || {};
    }
}

@rustbot label -E-needs-mcve

[chengniansun]

A duplicate

trait T {
    async fn foo() {
        || v
    }
}

[JohnTitor]

Fixed by #84168, marking as E-needs-test.

[JohnTitor]

The above PR should have a regression test, closing.