ICE: rustdoc on associated-types-path-1.rs attempted .def_id() on invalid res: Err

[matthiaskrgr]

Code

code from ./src/test/ui/associated-types/associated-types-path-1.rs

// Test that we have one and only one associated type per ref.

pub trait Foo {
    type A;
}
pub trait Bar {
    type A;
}

pub fn f1<T>(a: T, x: T::A) {} //~ERROR associated type `A` not found
pub fn f2<T: Foo + Bar>(a: T, x: T::A) {} //~ERROR ambiguous associated type `A`

pub fn main() {}

Meta

rustc --version --verbose:

rustdoc 1.50.0-nightly (1c389ffef 2020-11-24)
binary: rustdoc
commit-hash: 1c389ffeff814726dec325f0f2b0c99107df2673
commit-date: 2020-11-24
host: x86_64-unknown-linux-gnu
release: 1.50.0-nightly

Error output

error[E0220]: associated type `A` not found for `T`
  --> ./src/test/ui/associated-types/associated-types-path-1.rs:10:26
   |
10 | pub fn f1<T>(a: T, x: T::A) {} //~ERROR associated type `A` not found
   |                          ^ associated type `A` not found

error[E0221]: ambiguous associated type `A` in bounds of `T`
  --> ./src/test/ui/associated-types/associated-types-path-1.rs:11:34
   |
4  |     type A;
   |     ------- ambiguous `A` from `Foo`
...
7  |     type A;
   |     ------- ambiguous `A` from `Bar`
...
11 | pub fn f2<T: Foo + Bar>(a: T, x: T::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^ ambiguous associated type `A`
   |
help: use fully qualified syntax to disambiguate
   |
11 | pub fn f2<T: Foo + Bar>(a: T, x: <T as Bar>::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^^^^^^^^^^
help: use fully qualified syntax to disambiguate
   |
11 | pub fn f2<T: Foo + Bar>(a: T, x: <T as Foo>::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^^^^^^^^^^

thread 'rustc' panicked at 'attempted .def_id() on invalid res: Err', /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/compiler/rustc_hir/src/def.rs:408:32
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 1.50.0-nightly (1c389ffef 2020-11-24) running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack
error: aborting due to 2 previous errors

Some errors have detailed explanations: E0220, E0221.
For more information about an error, try `rustc --explain E0220`.

Backtrace

error[E0220]: associated type `A` not found for `T`
  --> ./src/test/ui/associated-types/associated-types-path-1.rs:10:26
   |
10 | pub fn f1<T>(a: T, x: T::A) {} //~ERROR associated type `A` not found
   |                          ^ associated type `A` not found

error[E0221]: ambiguous associated type `A` in bounds of `T`
  --> ./src/test/ui/associated-types/associated-types-path-1.rs:11:34
   |
4  |     type A;
   |     ------- ambiguous `A` from `Foo`
...
7  |     type A;
   |     ------- ambiguous `A` from `Bar`
...
11 | pub fn f2<T: Foo + Bar>(a: T, x: T::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^ ambiguous associated type `A`
   |
help: use fully qualified syntax to disambiguate
   |
11 | pub fn f2<T: Foo + Bar>(a: T, x: <T as Bar>::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^^^^^^^^^^
help: use fully qualified syntax to disambiguate
   |
11 | pub fn f2<T: Foo + Bar>(a: T, x: <T as Foo>::A) {} //~ERROR ambiguous associated type `A`
   |                                  ^^^^^^^^^^^^^

thread 'rustc' panicked at 'attempted .def_id() on invalid res: Err', /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/compiler/rustc_hir/src/def.rs:408:32
stack backtrace:
   0:     0x7fbb8f223e30 - std::backtrace_rs::backtrace::libunwind::trace::h746c3e9529d524bc
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
   1:     0x7fbb8f223e30 - std::backtrace_rs::backtrace::trace_unsynchronized::h86340908ff889faa
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fbb8f223e30 - std::sys_common::backtrace::_print_fmt::h43f85f9b18230404
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7fbb8f223e30 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc132ae1a5b5aa7cd
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys_common/backtrace.rs:46:22
   4:     0x7fbb8f296c4c - core::fmt::write::hdf023a0036d2a25f
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/core/src/fmt/mod.rs:1078:17
   5:     0x7fbb8f2159a2 - std::io::Write::write_fmt::h8580846154bcb66a
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/io/mod.rs:1519:15
   6:     0x7fbb8f227a95 - std::sys_common::backtrace::_print::h7ee55fed88d107a3
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys_common/backtrace.rs:49:5
   7:     0x7fbb8f227a95 - std::sys_common::backtrace::print::h54a7d3e52a524177
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys_common/backtrace.rs:36:9
   8:     0x7fbb8f227a95 - std::panicking::default_hook::{{closure}}::h60921e857bf55a40
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:208:50
   9:     0x7fbb8f2275ea - std::panicking::default_hook::hf0f9afb1017317fc
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:225:9
  10:     0x7fbb8fab4bb8 - rustc_driver::report_ice::ha25ae86a5858acc3
  11:     0x7fbb8f228396 - std::panicking::rust_panic_with_hook::h8d66bf42b407aaea
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:595:17
  12:     0x7fbb8f227eb7 - std::panicking::begin_panic_handler::{{closure}}::hde71edcd925d0c5e
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:497:13
  13:     0x7fbb8f2242ec - std::sys_common::backtrace::__rust_end_short_backtrace::h8a3c7d6cea578919
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys_common/backtrace.rs:141:18
  14:     0x7fbb8f227e19 - rust_begin_unwind
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:493:5
  15:     0x7fbb8f227dcb - std::panicking::begin_panic_fmt::hee67ce14b77d0396
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/panicking.rs:435:5
  16:     0x55d873ee0428 - rustc_hir::def::Res<Id>::def_id::{{closure}}::h06aeb0acc3e82fae
  17:     0x55d8740cda3d - rustdoc::clean::utils::register_res::h9cf2ca016844dce1
  18:     0x55d8740cd5b1 - rustdoc::clean::utils::resolve_type::hc4dd6a14930238e2
  19:     0x55d8740412af - <rustc_hir::hir::Ty as rustdoc::clean::Clean<rustdoc::clean::types::Type>>::clean::h7e12b892841ced7b
  20:     0x55d873e61dcf - <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::h64c59269cd1e2f54
  21:     0x55d87403e666 - <(&rustc_hir::hir::FnDecl,A) as rustdoc::clean::Clean<rustdoc::clean::types::FnDecl>>::clean::h0d96c315d7646885
  22:     0x55d8740ce18e - rustdoc::clean::utils::enter_impl_trait::h89ecd5f85c6cf117
  23:     0x55d874046339 - <(&rustc_hir::hir::Item,core::option::Option<rustc_span::symbol::Ident>) as rustdoc::clean::Clean<alloc::vec::Vec<rustdoc::clean::types::Item>>>::clean::h6efe2622d62f0879
  24:     0x55d87415201f - <alloc::vec::Vec<T,A> as alloc::vec::SpecExtend<T,I>>::spec_extend::hbf27f2437fec8031
  25:     0x55d8740cede8 - <rustdoc::doctree::Module as rustdoc::clean::Clean<rustdoc::clean::types::Item>>::clean::hee8955bac14e83bc
  26:     0x55d8740c8153 - rustdoc::clean::utils::krate::h68bb50ab032123ce
  27:     0x55d873e43b3b - rustdoc::core::run_global_ctxt::h7cf39be6ea65128e
  28:     0x55d873ebdece - rustc_interface::passes::QueryContext::enter::hedb615e17429b641
  29:     0x55d873fb3917 - rustc_interface::interface::create_compiler_and_run::h25fa5935e40978f2
  30:     0x55d873e5a0d3 - rustdoc::main_options::h8a5cda9c1c8c625b
  31:     0x55d873fa4a68 - rustc_span::with_session_globals::h7a83fbbd64fb6823
  32:     0x55d873e8b30e - std::sys_common::backtrace::__rust_begin_short_backtrace::h50722f4a01515f7b
  33:     0x55d873fbd03a - core::ops::function::FnOnce::call_once{{vtable.shim}}::h22276985fb540191
  34:     0x7fbb8f23765a - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hea1090dbdcecbf5a
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/alloc/src/boxed.rs:1318:9
  35:     0x7fbb8f23765a - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8d5723d3912bd325
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/alloc/src/boxed.rs:1318:9
  36:     0x7fbb8f23765a - std::sys::unix::thread::Thread::new::thread_start::hc17a425ca2995724
                               at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/std/src/sys/unix/thread.rs:71:17
  37:     0x7fbb8f1133e9 - start_thread
  38:     0x7fbb8eef9293 - __GI___clone
  39:                0x0 - <unknown>

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-nightly (1c389ffef 2020-11-24) running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack
error: aborting due to 2 previous errors

Some errors have detailed explanations: E0220, E0221.
For more information about an error, try `rustc --explain E0220`.

[jyn514]

MCVE:

pub fn f1<T>(x: T::A) {}

Assigning P-low by the same rationale as #79496 (comment), but I expect this to be much easier to fix than the other ICEs that are outside of rustdoc proper.

[matthiaskrgr]

No longer crashing

error[E0220]: associated type `A` not found for `T`
 --> out.rs:3:20
  |
3 | pub fn f1<T>(x: T::A) {}
  |                    ^ associated type `A` not found