ICE: panicked at 'called Option::unwrap() on a None value', compiler/rustc_middle/src/ty/sty.rs

[chengniansun]

Code

#![no_core]
#[lang = "sized"]
trait Sized {}
#[lang = "deref"]
trait Deref {}
fn test() {
    epriv()
}

Meta

rustc --version --verbose:

rustc 1.49.0-nightly (4f7612ac1 2020-10-31)
binary: rustc
commit-hash: 4f7612ac1499258025077f1fd05d2f429f9accfb
commit-date: 2020-10-31
host: x86_64-unknown-linux-gnu
release: 1.49.0-nightly

Error output

error[E0425]: cannot find function `epriv` in this scope
 --> reduced_mutant.rs:7:5
  |
7 |     epriv()
  |     ^^^^^ not found in this scope

error[E0658]: language items are subject to change
 --> reduced_mutant.rs:2:1
  |
2 | #[lang = "sized"]
  | ^^^^^^^^^^^^^^^^^
  |
  = help: add `#![feature(lang_items)]` to the crate attributes to enable

error[E0658]: language items are subject to change
 --> reduced_mutant.rs:4:1
  |
4 | #[lang = "deref"]
  | ^^^^^^^^^^^^^^^^^
  |
  = help: add `#![feature(lang_items)]` to the crate attributes to enable

error[E0658]: the `#[no_core]` attribute is an experimental feature
 --> reduced_mutant.rs:1:1
  |
1 | #![no_core]
  | ^^^^^^^^^^^
  |
  = note: see issue #29639 <https://github.com/rust-lang/rust/issues/29639> for more information
  = help: add `#![feature(no_core)]` to the crate attributes to enable

error[E0601]: `main` function not found in crate `reduced_mutant`
 --> reduced_mutant.rs:1:1
  |
1 | / #![no_core]
2 | | #[lang = "sized"]
3 | | trait Sized {}
4 | | #[lang = "deref"]
... |
7 | |     epriv()
8 | | }
  | |_^ consider adding a `main` function to `reduced_mutant.rs`

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_middle/src/ty/sty.rs:1142:14
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.49.0-nightly (4f7612ac1 2020-10-31) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `test`
#1 [typeck_item_bodies] type-checking all item bodies
end of query stack
error: aborting due to 5 previous errors

Some errors have detailed explanations: E0425, E0601, E0658.
For more information about an error, try `rustc --explain E0425`.

Backtrace

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_middle/src/ty/sty.rs:1142:14
stack backtrace:
   0: rust_begin_unwind
             at /rustc/4f7612ac1499258025077f1fd05d2f429f9accfb/library/std/src/panicking.rs:495:5
   1: core::panicking::panic_fmt
             at /rustc/4f7612ac1499258025077f1fd05d2f429f9accfb/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/4f7612ac1499258025077f1fd05d2f429f9accfb/library/core/src/panicking.rs:50:5
   3: rustc_middle::ty::sty::ProjectionTy::from_ref_and_name
   4: <rustc_trait_selection::autoderef::Autoderef as core::iter::traits::iterator::Iterator>::next
   5: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_call
   6: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
   7: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
   8: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
   9: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  10: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  11: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  12: rustc_typeck::check::check::check_fn
  13: rustc_infer::infer::InferCtxtBuilder::enter
  14: rustc_typeck::check::typeck
  15: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::typeck>::compute
  16: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  17: rustc_data_structures::stack::ensure_sufficient_stack
  18: rustc_query_system::query::plumbing::get_query_impl
  19: rustc_query_system::query::plumbing::ensure_query_impl
  20: rustc_typeck::check::typeck_item_bodies
  21: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::typeck_item_bodies>::compute
  22: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  23: rustc_data_structures::stack::ensure_sufficient_stack
  24: rustc_query_system::query::plumbing::get_query_impl
  25: rustc_typeck::check_crate
  26: rustc_interface::passes::analysis
  27: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::analysis>::compute
  28: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  29: rustc_data_structures::stack::ensure_sufficient_stack
  30: rustc_query_system::query::plumbing::get_query_impl
  31: rustc_interface::passes::QueryContext::enter
  32: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  33: rustc_span::with_source_map
  34: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

NOTE: The bug is found by our work-in-progress compiler testing tool Kira, and the test program is reduced/minimized by Perses

[jonas-schievink]

This is because trait Deref {} is missing the associated Target type, so closing in favor of #9307