clippy ICEs: "Not a type: DefIndex(1359)', compiler/rustc_metadata/src/rmeta/decoder.rs:908:32"

[matthiaskrgr]

Saw this while running clippy 5c6cd87 compiled with rustc rustc 1.52.0-nightly (a8486b64b 2021-02-24) in the alacritty git repo:

Error output

    Checking alacritty v0.8.0-dev (/home/matthias/vcs/github/alacritty/alacritty)
thread 'rustc' panicked at 'Not a type: DefIndex(1359)', compiler/rustc_metadata/src/rmeta/decoder.rs:908:32
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-clippy/issues/new

note: Clippy version: clippy 0.1.52 (928e72dd1 2021-02-25)

query stack during panic:
#0 [type_of] computing type of `config::color::_::_serde::de::Visitor::Value`
#1 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `alacritty`

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

Backtrace

    Checking alacritty v0.8.0-dev (/home/matthias/vcs/github/alacritty/alacritty)
thread 'rustc' panicked at 'Not a type: DefIndex(1359)', compiler/rustc_metadata/src/rmeta/decoder.rs:908:32
stack backtrace:
 0:     0x7f6069250d20 - std::backtrace_rs::backtrace::libunwind::trace::h9d49145f95eb5894
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
 1:     0x7f6069250d20 - std::backtrace_rs::backtrace::trace_unsynchronized::hab1d020365bb6864
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
 2:     0x7f6069250d20 - std::sys_common::backtrace::_print_fmt::h7659588431e304bd
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:67:5
 3:     0x7f6069250d20 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h09f4a9e3befae3c7
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:46:22
 4:     0x7f60692c146c - core::fmt::write::hf3fdfde304b9a088
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/core/src/fmt/mod.rs:1092:17
 5:     0x7f6069244062 - std::io::Write::write_fmt::h1cb850689c7116f0
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/io/mod.rs:1568:15
 6:     0x7f6069254bc5 - std::sys_common::backtrace::_print::hdbccd5aa093ba544
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:49:5
 7:     0x7f6069254bc5 - std::sys_common::backtrace::print::hc639c4f320222558
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:36:9
 8:     0x7f6069254bc5 - std::panicking::default_hook::{{closure}}::hdb012dd7a485bb5d
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:208:50
 9:     0x7f6069254673 - std::panicking::default_hook::h75facbce77b6ba91
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:225:9
10:     0x562d8b504326 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hf670d2338201faaa
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:1560:9
11:     0x562d8b505386 - clippy_driver::report_clippy_ice::ha011a557ce32c801
                             at /home/matthias/vcs/github/rust-clippy/src/driver.rs:130:5
12:     0x562d8b507b25 - clippy_driver::ICE_HOOK::{{closure}}::{{closure}}::h81e5233532c5ccb3
                             at /home/matthias/vcs/github/rust-clippy/src/driver.rs:124:37
13:     0x7f605a22f526 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h446469f4ecdc815b
                             at /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:1560:9
14:     0x7f605a232179 - proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::enter::{{closure}}::{{closure}}::h5a3b94cc035cfa07
                             at /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:320:21
15:     0x7f60692554c6 - std::panicking::rust_panic_with_hook::hbcaa5de2cb5e22d5
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:595:17
16:     0x7f6069254fe7 - std::panicking::begin_panic_handler::{{closure}}::h4ee6cde415c8f62d
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:497:13
17:     0x7f60692511dc - std::sys_common::backtrace::__rust_end_short_backtrace::h895319f2d3f611c0
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:141:18
18:     0x7f6069254f49 - rust_begin_unwind
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:493:5
19:     0x7f6069254efb - std::panicking::begin_panic_fmt::h0262e6b4d4041adf
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:435:5
20:     0x7f606b404703 - rustc_metadata::rmeta::decoder::<impl rustc_metadata::creader::CrateMetadataRef>::get_type::h0f7702e8fa35bbb2
21:     0x7f606b44d90d - rustc_metadata::rmeta::decoder::cstore_impl::provide_extern::type_of::he521e5ab693b86e7
22:     0x7f606bd01c88 - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::haad0024fe8f5a7d2
23:     0x7f606b0d00fb - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h5a242bc967412ecf
24:     0x7f606b0af973 - rustc_data_structures::stack::ensure_sufficient_stack::h8b47dd27a73cafbe
25:     0x7f606b08cb37 - rustc_query_system::query::plumbing::force_query_with_job::h7032cab6de61fbf2
26:     0x7f606b06f32f - rustc_query_system::query::plumbing::get_query_impl::ha96d8281a4a739f8
27:     0x7f606b0c0e4a - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::type_of::hdaa39503a441e1f1
28:     0x562d8b65df6e - rustc_middle::ty::query::TyCtxtAt::type_of::hd38e60fdbe072970
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_middle/src/ty/query/mod.rs:205:17
29:     0x562d8b65df6e - rustc_middle::ty::query::<impl rustc_middle::ty::context::TyCtxt>::type_of::h4173330feb6c2294
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_middle/src/ty/query/mod.rs:186:17
30:     0x562d8b65df6e - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::h32f67de45e3d4b1e
                             at /home/matthias/vcs/github/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:136:30
31:     0x562d8b65d57d - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::h32f67de45e3d4b1e
                             at /home/matthias/vcs/github/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:114:25
32:     0x562d8b91ca05 - rustc_hir::intravisit::walk_block::h7a2182a7c25433aa
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:1084:5
33:     0x562d8b8b2bc4 - rustc_hir::intravisit::Visitor::visit_block::h73882cbd0875fbc4
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:354:9
34:     0x562d8ba2dc29 - rustc_hir::intravisit::walk_expr::he36c8d266e8e3497
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:1173:13
35:     0x562d8b65e3bd - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::h32f67de45e3d4b1e
                             at /home/matthias/vcs/github/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:178:9
36:     0x562d8b9eb0b8 - rustc_hir::intravisit::walk_body::h765df2df0f9a42a5
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:506:5
37:     0x562d8b8b2b44 - rustc_hir::intravisit::Visitor::visit_body::h97531e8750c67478
                             at /home/matthias/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:320:9
38:     0x562d8b65ccd5 - <clippy_lints::default_numeric_fallback::DefaultNumericFallback as rustc_lint::passes::LateLintPass>::check_body::hb0631384b47e3da2
                             at /home/matthias/vcs/github/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:54:9
39:     0x7f606a8efd92 - <rustc_lint::late::LateLintPassObjects as rustc_lint::passes::LateLintPass>::check_body::h699daf59875dce36
40:     0x7f6069b24e9b - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_nested_body::he58e9e6b24e9d9c0
41:     0x7f6069b25186 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_fn::hac0cd372390dff45
42:     0x7f6069b6b27b - rustc_hir::intravisit::walk_impl_item::h5bb649e8ba81efef
43:     0x7f6069b262d1 - rustc_hir::intravisit::Visitor::visit_nested_impl_item::hdf136acf27ef1810
44:     0x7f6069b6b96c - rustc_hir::intravisit::walk_impl_item_ref::h39360467acb6f1e2
45:     0x7f6069b6ca7a - rustc_hir::intravisit::walk_item::h2f37f1d91082318b
46:     0x7f6069b25d25 - rustc_hir::intravisit::Visitor::visit_nested_item::hcd30d874837a4042
47:     0x7f6069b24b59 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_stmt::hb862526b553e6363
48:     0x7f6069b6ac79 - rustc_hir::intravisit::walk_block::hb9dfb3d8deaaa8eb
49:     0x7f6069b24b99 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_block::h69ffeb043eb0f6ec
50:     0x7f6069b24a27 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_expr::hfe4f59005f7421e1
51:     0x7f6069b24ea6 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_nested_body::he58e9e6b24e9d9c0
52:     0x7f6069b25186 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_fn::hac0cd372390dff45
53:     0x7f6069b6b27b - rustc_hir::intravisit::walk_impl_item::h5bb649e8ba81efef
54:     0x7f6069b262d1 - rustc_hir::intravisit::Visitor::visit_nested_impl_item::hdf136acf27ef1810
55:     0x7f6069b6b96c - rustc_hir::intravisit::walk_impl_item_ref::h39360467acb6f1e2
56:     0x7f6069b6ca7a - rustc_hir::intravisit::walk_item::h2f37f1d91082318b
57:     0x7f6069b25d25 - rustc_hir::intravisit::Visitor::visit_nested_item::hcd30d874837a4042
58:     0x7f6069b6bf38 - rustc_hir::intravisit::walk_mod::h169a052681c2134e
59:     0x7f6069b252cf - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_mod::h50f560318c71a862
60:     0x7f6069b6cb09 - rustc_hir::intravisit::walk_item::h2f37f1d91082318b
61:     0x7f6069b25d25 - rustc_hir::intravisit::Visitor::visit_nested_item::hcd30d874837a4042
62:     0x7f6069b6bf38 - rustc_hir::intravisit::walk_mod::h169a052681c2134e
63:     0x7f6069b252cf - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_mod::h50f560318c71a862
64:     0x7f6069b6cb09 - rustc_hir::intravisit::walk_item::h2f37f1d91082318b
65:     0x7f6069b25d25 - rustc_hir::intravisit::Visitor::visit_nested_item::hcd30d874837a4042
66:     0x7f6069b6bf38 - rustc_hir::intravisit::walk_mod::h169a052681c2134e
67:     0x7f6069b252cf - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_mod::h50f560318c71a862
68:     0x7f6069b6accf - rustc_hir::intravisit::walk_crate::h56516cd5271fbde1
69:     0x7f6069b20fec - rustc_lint::late::late_lint_pass_crate::h68fca22b203b40c7
70:     0x7f606b7865ef - rustc_lint::late::late_lint_crate::h8b056da490fd5163
71:     0x7f606b7bc2d3 - rustc_data_structures::sync::join::h1e87f8b6f730a184
72:     0x7f606b7a3c85 - std::panic::catch_unwind::h52b42338dd242d3f
73:     0x7f606b78c36f - rustc_session::utils::<impl rustc_session::session::Session>::time::hb76d107dd0ea1521
74:     0x7f606b7920ac - rustc_interface::passes::analysis::h1be2fa253172941a
75:     0x7f606a27ea0e - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::h85fa16d3332afce7
76:     0x7f606bccc5c9 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h796e12c98e2566ac
77:     0x7f606bc4165f - rustc_data_structures::stack::ensure_sufficient_stack::h76fb6483c26c7f6b
78:     0x7f606bbfc54a - rustc_query_system::query::plumbing::force_query_with_job::h90d3fef7e56f1800
79:     0x7f606bbc469b - rustc_query_system::query::plumbing::get_query_impl::hb04441add7cec8aa
80:     0x7f606bca3c6f - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis::h27d2dd58d2fc9be8
81:     0x7f606b77e83b - rustc_interface::passes::QueryContext::enter::h8a95f60ada89ef7e
82:     0x7f606b74f06d - rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter::h39531375bcd2fda9
83:     0x7f606b77fda1 - rustc_span::with_source_map::hf3c84f193adf9eda
84:     0x7f606b75002a - rustc_interface::interface::create_compiler_and_run::he227014f8377cd9b
85:     0x7f606b74e238 - scoped_tls::ScopedKey<T>::set::h45bce0d39c421236
86:     0x7f606b74e8fc - std::sys_common::backtrace::__rust_begin_short_backtrace::h07189c72057db042
87:     0x7f606b76d8da - core::ops::function::FnOnce::call_once{{vtable.shim}}::h58a4726aa1e9868c
88:     0x7f60692656ca - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hdc51fe7e73bc86bf
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/alloc/src/boxed.rs:1546:9
89:     0x7f60692656ca - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he605738a76b56d9d
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/alloc/src/boxed.rs:1546:9
90:     0x7f60692656ca - std::sys::unix::thread::Thread::new::thread_start::he44b12fd83e74919
                             at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys/unix/thread.rs:71:17
91:     0x7f6069151299 - start_thread
92:     0x7f6068f33153 - clone
93:                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-clippy/issues/new

note: Clippy version: clippy 0.1.52 (928e72dd1 2021-02-25)

query stack during panic:
#0 [type_of] computing type of `config::color::_::_serde::de::Visitor::Value`
#1 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `alacritty`

Made the issue so hopefully people see this and we don't get bombarded with "clippy crashes on my project" tickets in the upcomming days. 😅

I'm not sure yet if we can reproduce the ice with pure rustc or if it is bound to clippy somehow.
Looks like the default_numeric_fallback lint is involved:
35: 0x562d8b65e3bd - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::h32f67de45e3d4b1e at /home/matthias/vcs/github/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:178:9

This is reproducible in rustc master now and will hit nightly 2021-02-25

[anall]

Possible reduced repro case, although the backtrace for this diverges after rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::haad0024fe8f5a7d2.

struct Test {}
trait SomeTrait {
  type Outer;

  fn broken() -> Self::Outer;
}

struct Inner {}
impl SomeTrait for Inner {
  type Outer = Test;

  fn broken() -> Self::Outer {
    Self::Outer{}
  }
}

fn main() {}

Gives:

error: internal compiler error: compiler/rustc_typeck/src/collect/type_of.rs:279:17: associated type missing default
 --> src/main.rs:3:3
  |
3 |   type Outer;
  |   ^^^^^^^^^^^

thread 'rustc' panicked at 'Box<Any>', /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panic.rs:59:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.52 (7dd6d5ed5 2021-02-26)

query stack during panic:
#0 [type_of] computing type of `SomeTrait::Outer`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

error: could not compile `ice6792`

Backtrace

stack backtrace:
   0:     0x7f31d415cd20 - std::backtrace_rs::backtrace::libunwind::trace::h9d49145f95eb5894
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
   1:     0x7f31d415cd20 - std::backtrace_rs::backtrace::trace_unsynchronized::hab1d020365bb6864
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f31d415cd20 - std::sys_common::backtrace::_print_fmt::h7659588431e304bd
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7f31d415cd20 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h09f4a9e3befae3c7
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:46:22
   4:     0x7f31d41cd46c - core::fmt::write::hf3fdfde304b9a088
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/core/src/fmt/mod.rs:1092:17
   5:     0x7f31d4150062 - std::io::Write::write_fmt::h1cb850689c7116f0
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/io/mod.rs:1568:15
   6:     0x7f31d4160bc5 - std::sys_common::backtrace::_print::hdbccd5aa093ba544
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:49:5
   7:     0x7f31d4160bc5 - std::sys_common::backtrace::print::hc639c4f320222558
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys_common/backtrace.rs:36:9
   8:     0x7f31d4160bc5 - std::panicking::default_hook::{{closure}}::hdb012dd7a485bb5d
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:208:50
   9:     0x7f31d4160673 - std::panicking::default_hook::h75facbce77b6ba91
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:225:9
  10:     0x557b6b44f7d6 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h08d9a91348e0a8c4
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:1560:9
  11:     0x557b6b44ae86 - clippy_driver::report_clippy_ice::haae22f8418b99752
                               at /home/anall/Projects/rust-clippy/src/driver.rs:130:5
  12:     0x557b6b454575 - clippy_driver::ICE_HOOK::{{closure}}::{{closure}}::hf582fb04cef0dc62
                               at /home/anall/Projects/rust-clippy/src/driver.rs:124:37
  13:     0x7f31d41614c6 - std::panicking::rust_panic_with_hook::hbcaa5de2cb5e22d5
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/panicking.rs:595:17
  14:     0x7f31d4d410f6 - std::panicking::begin_panic::{{closure}}::he22afd489be7f839
  15:     0x7f31d4d41029 - std::sys_common::backtrace::__rust_end_short_backtrace::h8864891dcfcacf13
  16:     0x7f31d4d9faa2 - std::panicking::begin_panic::h978d7b6600883251
  17:     0x7f31d4d339c0 - std::panic::panic_any::h2f13f43e56bf09a7
  18:     0x7f31d4d2f8b5 - rustc_errors::HandlerInner::span_bug::h851309a44ebcd5d5
  19:     0x7f31d4d2fbf3 - rustc_errors::Handler::span_bug::h42213a9313121990
  20:     0x7f31d4d99292 - rustc_middle::ty::context::tls::with_opt::h553203d5c637e61d
  21:     0x7f31d6983820 - rustc_middle::util::bug::opt_span_bug_fmt::hdab485fa6a7ec0e2
  22:     0x7f31d4d9930c - rustc_middle::util::bug::span_bug_fmt::h9a5397aa7e1ee77a
  23:     0x7f31d5e3aa40 - rustc_typeck::collect::type_of::type_of::hfbcd5f80eee70212
  24:     0x7f31d6c0dc88 - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::haad0024fe8f5a7d2
  25:     0x7f31d5fdc0fb - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h5a242bc967412ecf
  26:     0x7f31d5fbb973 - rustc_data_structures::stack::ensure_sufficient_stack::h8b47dd27a73cafbe
  27:     0x7f31d5f98b37 - rustc_query_system::query::plumbing::force_query_with_job::h7032cab6de61fbf2
  28:     0x7f31d5f7b32f - rustc_query_system::query::plumbing::get_query_impl::ha96d8281a4a739f8
  29:     0x7f31d5fcce4a - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::type_of::hdaa39503a441e1f1
  30:     0x557b6b79cd3e - rustc_middle::ty::query::TyCtxtAt::type_of::h60d169ea3d17af82
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_middle/src/ty/query/mod.rs:205:17
  31:     0x557b6b79cd3e - rustc_middle::ty::query::<impl rustc_middle::ty::context::TyCtxt>::type_of::h05c6dbfd01b82732
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_middle/src/ty/query/mod.rs:186:17
  32:     0x557b6b79cd3e - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::he0e735c9853569f0
                               at /home/anall/Projects/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:137:30
  33:     0x557b6b504d65 - rustc_hir::intravisit::walk_block::ha790e9fb0ce72f53
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:1084:5
  34:     0x557b6b7aabe4 - rustc_hir::intravisit::Visitor::visit_block::hdaf251827711c68a
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:354:9
  35:     0x557b6b5d5c19 - rustc_hir::intravisit::walk_expr::h0559eeea47c7c599
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:1173:13
  36:     0x557b6b79d18d - <clippy_lints::default_numeric_fallback::NumericFallbackVisitor as rustc_hir::intravisit::Visitor>::visit_expr::he0e735c9853569f0
                               at /home/anall/Projects/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:179:9
  37:     0x557b6b5d28d8 - rustc_hir::intravisit::walk_body::ha0ac9fabff89d1c2
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:506:5
  38:     0x557b6b7aab64 - rustc_hir::intravisit::Visitor::visit_body::h2345aa62a5de0321
                               at /home/anall/.rustup/toolchains/nightly-2021-02-25-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/compiler/rustc_hir/src/intravisit.rs:320:9
  39:     0x557b6b79baa5 - <clippy_lints::default_numeric_fallback::DefaultNumericFallback as rustc_lint::passes::LateLintPass>::check_body::he1337052e55869ed
                               at /home/anall/Projects/rust-clippy/clippy_lints/src/default_numeric_fallback.rs:54:9
  40:     0x7f31d57fbd92 - <rustc_lint::late::LateLintPassObjects as rustc_lint::passes::LateLintPass>::check_body::h699daf59875dce36
  41:     0x7f31d4a30e9b - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_nested_body::he58e9e6b24e9d9c0
  42:     0x7f31d4a31186 - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_fn::hac0cd372390dff45
  43:     0x7f31d4a7727b - rustc_hir::intravisit::walk_impl_item::h5bb649e8ba81efef
  44:     0x7f31d4a322d1 - rustc_hir::intravisit::Visitor::visit_nested_impl_item::hdf136acf27ef1810
  45:     0x7f31d4a7796c - rustc_hir::intravisit::walk_impl_item_ref::h39360467acb6f1e2
  46:     0x7f31d4a78a7a - rustc_hir::intravisit::walk_item::h2f37f1d91082318b
  47:     0x7f31d4a31d25 - rustc_hir::intravisit::Visitor::visit_nested_item::hcd30d874837a4042
  48:     0x7f31d4a77f38 - rustc_hir::intravisit::walk_mod::h169a052681c2134e
  49:     0x7f31d4a312cf - <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_mod::h50f560318c71a862
  50:     0x7f31d4a76ccf - rustc_hir::intravisit::walk_crate::h56516cd5271fbde1
  51:     0x7f31d4a2cfec - rustc_lint::late::late_lint_pass_crate::h68fca22b203b40c7
  52:     0x7f31d66925ef - rustc_lint::late::late_lint_crate::h8b056da490fd5163
  53:     0x7f31d66c82d3 - rustc_data_structures::sync::join::h1e87f8b6f730a184
  54:     0x7f31d66afc85 - std::panic::catch_unwind::h52b42338dd242d3f
  55:     0x7f31d669836f - rustc_session::utils::<impl rustc_session::session::Session>::time::hb76d107dd0ea1521
  56:     0x7f31d669e0ac - rustc_interface::passes::analysis::h1be2fa253172941a
  57:     0x7f31d518aa0e - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::h85fa16d3332afce7
  58:     0x7f31d6bd85c9 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h796e12c98e2566ac
  59:     0x7f31d6b4d65f - rustc_data_structures::stack::ensure_sufficient_stack::h76fb6483c26c7f6b
  60:     0x7f31d6b0854a - rustc_query_system::query::plumbing::force_query_with_job::h90d3fef7e56f1800
  61:     0x7f31d6ad069b - rustc_query_system::query::plumbing::get_query_impl::hb04441add7cec8aa
  62:     0x7f31d6bafc6f - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis::h27d2dd58d2fc9be8
  63:     0x7f31d668a83b - rustc_interface::passes::QueryContext::enter::h8a95f60ada89ef7e
  64:     0x7f31d665b06d - rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter::h39531375bcd2fda9
  65:     0x7f31d668bda1 - rustc_span::with_source_map::hf3c84f193adf9eda
  66:     0x7f31d665c02a - rustc_interface::interface::create_compiler_and_run::he227014f8377cd9b
  67:     0x7f31d665a238 - scoped_tls::ScopedKey<T>::set::h45bce0d39c421236
  68:     0x7f31d665a8fc - std::sys_common::backtrace::__rust_begin_short_backtrace::h07189c72057db042
  69:     0x7f31d66798da - core::ops::function::FnOnce::call_once{{vtable.shim}}::h58a4726aa1e9868c
  70:     0x7f31d41716ca - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hdc51fe7e73bc86bf
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/alloc/src/boxed.rs:1546:9
  71:     0x7f31d41716ca - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he605738a76b56d9d
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/alloc/src/boxed.rs:1546:9
  72:     0x7f31d41716ca - std::sys::unix::thread::Thread::new::thread_start::he44b12fd83e74919
                               at /rustc/a8486b64b0c87dabd045453b6c81500015d122d6/library/std/src/sys/unix/thread.rs:71:17
  73:     0x7f31d405e609 - start_thread
  74:     0x7f31d3e36293 - clone
  75:                0x0 - <unknown>

I don't think this has anything to do with default_numeric_fallback because if I disable that lint the backtrace implicates inconsistent_struct_constructor. But I'm pretty sure this is rustc side.

As far as I can tell this comes calling self.cx.tcx.type_of(def_id) with def_id of DefId(0:5 ~ ice6792[1241]::SomeTrait::Outer)

There are two ways you can change the reduced example to prevent the ICE:

• Giving type Outer a default type (and adding #![feature(associated_type_defaults)])
• Changing from fn broken() -> Self::Outer { Self::Outer{} } to fn broken() -> Self::Outer { Test{} } ( I tried swapping other instances of Self::Outer to Test, but is that specific one that apparently causes the ICE )

[Y-Nak]

I don't think this has anything to do with default_numeric_fallback because if I disable that lint the backtrace implicates inconsistent_struct_constructor.

I think default_numeric_fallback is involved in the ICE because it has the same problematic lines as inconsistent_struct_constructor, the ICE is caused by here in default_numeric_fallback and also here in inconsistent_struct_constructor.

I suppose we could solve this issue just by replacing the lines with cx.typeck_results().expr_ty(expr).
And this would also fix #6793.

[XiangpengHao]

Hi, I'm using the nightly clippy but can still reproduce the issue, do I miss anything?

struct Test {}
trait SomeTrait {
  type Outer;

  fn broken() -> Self::Outer;
}

struct Inner {}
impl SomeTrait for Inner {
  type Outer = Test;

  fn broken() -> Self::Outer {
    Self::Outer{}
  }
}

fn main() {}

error: internal compiler error: compiler/rustc_typeck/src/collect/type_of.rs:278:17: associated type missing default
  --> src/main.rs:22:3
   |
22 |   type Outer;
   |   ^^^^^^^^^^^

thread 'rustc' panicked at 'Box<Any>', /rustc/3a5d45f68cadc8fff4fbb557780f92b403b19c19/library/std/src/panic.rs:59:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.52 (3a5d45f 2021-03-09)

query stack during panic:
#0 [type_of] computing type of `SomeTrait::Outer`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

error: could not compile `rust_test`

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