ICE: failed to normalize with proc_macro in normalize_erasing_regions.rs

[langston-barrett]

This is a fuzzed test case, found with tree-splicer and minimized with treereduce. Please let me know (and many apologies) if it's not helpful!

This happens on the same line as in these issues; though with a different query stack.

[EDIT: Links removed to avoid spurrious backlinks]

Some similar looking issues involve features, none seem to involve proc_macro. Search: https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-ICE+failed+to+normalize

Code

extern crate proc_macro;

trait Project {
    type Assoc;
}

#[proc_macro]
fn uwu() -> <() as Project>::Assoc {}

Meta

rustc --version --verbose:

rustc 1.70.0-nightly (22f247c6f 2023-03-13)
binary: rustc
commit-hash: 22f247c6f3ed388cb702d01c2ff27da658a8b353
commit-date: 2023-03-13
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7

Error output

error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:195:90: Failed to normalize <() as Project>::Assoc, maybe try to call `try_normalize_erasing_regions` instead

Backtrace

error: the `#[proc_macro]` attribute is only usable with crates of the `proc-macro` crate type
 --> ice.rs:7:1
  |
7 | #[proc_macro]
  | ^^^^^^^^^^^^^

warning: unused macro definition: `uwu`
 --> ice.rs:8:4
  |
8 | fn uwu() -> <() as Project>::Assoc {}
  |    ^^^
  |
  = note: `#[warn(unused_macros)]` on by default

error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:195:90: Failed to normalize <() as Project>::Assoc, maybe try to call `try_normalize_erasing_regions` instead

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/compiler/rustc_errors/src/lib.rs:1644:9
stack backtrace:
   0:     0x7fd22542051a - std::backtrace_rs::backtrace::libunwind::trace::h1ac6254167c780d9
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fd22542051a - std::backtrace_rs::backtrace::trace_unsynchronized::hec2af85915e24f36
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fd22542051a - std::sys_common::backtrace::_print_fmt::h58a4e3535fcce206
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7fd22542051a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h5107e13758b8321c
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fd225483c5e - core::fmt::write::h2e851dc027730d81
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/core/src/fmt/mod.rs:1232:17
   5:     0x7fd225413375 - std::io::Write::write_fmt::hca00074de9f85084
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/io/mod.rs:1684:15
   6:     0x7fd2254202e5 - std::sys_common::backtrace::_print::h870053c845cddf24
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7fd2254202e5 - std::sys_common::backtrace::print::hb56add862f96c5fd
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7fd22542305f - std::panicking::default_hook::{{closure}}::h636d4ba3ff8fdc46
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:271:22
   9:     0x7fd225422d9b - std::panicking::default_hook::hf29b58145ee6e43c
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:290:9
  10:     0x7fd2287630c5 - <rustc_driver_impl[74350ec99973fded]::DEFAULT_HOOK::{closure#0}::{closure#0} as core[2011dc7817943e09]::ops::function::FnOnce<(&core[2011dc7817943e09]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  11:     0x7fd22542389d - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h7342d57f33f6634f
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:2002:9
  12:     0x7fd22542389d - std::panicking::rust_panic_with_hook::hbf9ef936d990c16f
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:696:13
  13:     0x7fd228ccd5b1 - std[1337fb43929788f1]::panicking::begin_panic::<rustc_errors[9dbe0d28acf3471b]::ExplicitBug>::{closure#0}
  14:     0x7fd228cc8a36 - std[1337fb43929788f1]::sys_common::backtrace::__rust_end_short_backtrace::<std[1337fb43929788f1]::panicking::begin_panic<rustc_errors[9dbe0d28acf3471b]::ExplicitBug>::{closure#0}, !>
  15:     0x7fd228d4de86 - std[1337fb43929788f1]::panicking::begin_panic::<rustc_errors[9dbe0d28acf3471b]::ExplicitBug>
  16:     0x7fd228d19fe6 - std[1337fb43929788f1]::panic::panic_any::<rustc_errors[9dbe0d28acf3471b]::ExplicitBug>
  17:     0x7fd228d16866 - <rustc_errors[9dbe0d28acf3471b]::HandlerInner>::bug::<&alloc[b7ae3602ac956de8]::string::String>
  18:     0x7fd228d16530 - <rustc_errors[9dbe0d28acf3471b]::Handler>::bug::<&alloc[b7ae3602ac956de8]::string::String>
  19:     0x7fd228d0295b - rustc_middle[eaae5d2a0b8f0144]::util::bug::opt_span_bug_fmt::<rustc_span[18b84908941c7cdf]::span_encoding::Span>::{closure#0}
  20:     0x7fd228d013ba - rustc_middle[eaae5d2a0b8f0144]::ty::context::tls::with_opt::<rustc_middle[eaae5d2a0b8f0144]::util::bug::opt_span_bug_fmt<rustc_span[18b84908941c7cdf]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7fd228d01386 - rustc_middle[eaae5d2a0b8f0144]::ty::context::tls::with_context_opt::<rustc_middle[eaae5d2a0b8f0144]::ty::context::tls::with_opt<rustc_middle[eaae5d2a0b8f0144]::util::bug::opt_span_bug_fmt<rustc_span[18b84908941c7cdf]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7fd228d028a6 - rustc_middle[eaae5d2a0b8f0144]::util::bug::opt_span_bug_fmt::<rustc_span[18b84908941c7cdf]::span_encoding::Span>
  23:     0x7fd226e3c5c3 - rustc_middle[eaae5d2a0b8f0144]::util::bug::bug_fmt
  24:     0x7fd2269345c8 - <rustc_middle[eaae5d2a0b8f0144]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_type_ir[65f3a8acf733f7d2]::fold::TypeFolder<rustc_middle[eaae5d2a0b8f0144]::ty::context::TyCtxt>>::fold_ty
  25:     0x7fd228fb5119 - rustc_middle[eaae5d2a0b8f0144]::ty::util::fold_list::<rustc_middle[eaae5d2a0b8f0144]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder, rustc_middle[eaae5d2a0b8f0144]::ty::Ty, <&rustc_middle[eaae5d2a0b8f0144]::ty::list::List<rustc_middle[eaae5d2a0b8f0144]::ty::Ty> as rustc_type_ir[65f3a8acf733f7d2]::fold::TypeFoldable<rustc_middle[eaae5d2a0b8f0144]::ty::context::TyCtxt>>::try_fold_with<rustc_middle[eaae5d2a0b8f0144]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder>::{closure#0}>
  26:     0x7fd228fe8df5 - <rustc_middle[eaae5d2a0b8f0144]::ty::sty::FnSig as rustc_type_ir[65f3a8acf733f7d2]::fold::TypeFoldable<rustc_middle[eaae5d2a0b8f0144]::ty::context::TyCtxt>>::fold_with::<rustc_middle[eaae5d2a0b8f0144]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder>
  27:     0x7fd226bae47d - <rustc_passes[5734ea879e29deaf]::check_attr::CheckAttrVisitor>::check_proc_macro
  28:     0x7fd226fbf9ca - <rustc_passes[5734ea879e29deaf]::check_attr::CheckAttrVisitor>::check_attributes
  29:     0x7fd226fba9ca - <rustc_middle[eaae5d2a0b8f0144]::hir::map::Map>::visit_item_likes_in_module::<rustc_passes[5734ea879e29deaf]::check_attr::CheckAttrVisitor>
  30:     0x7fd226fba6b7 - rustc_passes[5734ea879e29deaf]::check_attr::check_mod_attrs
  31:     0x7fd227d9cd3e - rustc_query_system[f881c7f40ee7dcf0]::query::plumbing::try_execute_query::<rustc_query_impl[eb95ff51c492efdd]::queries::check_mod_attrs, rustc_query_impl[eb95ff51c492efdd]::plumbing::QueryCtxt>
  32:     0x7fd227d9c8c3 - <rustc_query_impl[eb95ff51c492efdd]::Queries as rustc_middle[eaae5d2a0b8f0144]::ty::query::QueryEngine>::check_mod_attrs
  33:     0x7fd226b478a8 - <core[2011dc7817943e09]::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures[75b47a18491287a9]::sync::par_for_each_in<&[rustc_hir[ca07edd3831bb6e2]::hir_id::OwnerId], <rustc_middle[eaae5d2a0b8f0144]::hir::map::Map>::par_for_each_module<rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#0}::{closure#1}::{closure#0}>::{closure#0}>::{closure#0}::{closure#0}> as core[2011dc7817943e09]::ops::function::FnOnce<()>>::call_once
  34:     0x7fd226b47748 - rustc_data_structures[75b47a18491287a9]::sync::par_for_each_in::<&[rustc_hir[ca07edd3831bb6e2]::hir_id::OwnerId], <rustc_middle[eaae5d2a0b8f0144]::hir::map::Map>::par_for_each_module<rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#0}::{closure#1}::{closure#0}>::{closure#0}>
  35:     0x7fd226b47516 - <core[2011dc7817943e09]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#0}::{closure#1}> as core[2011dc7817943e09]::ops::function::FnOnce<()>>::call_once
  36:     0x7fd226b471b5 - <rustc_session[a360c2d099171c08]::session::Session>::time::<(), rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#0}>
  37:     0x7fd226b461a8 - rustc_interface[ceda1fd77ec39e1b]::passes::analysis
  38:     0x7fd227f81a4c - rustc_query_system[f881c7f40ee7dcf0]::query::plumbing::try_execute_query::<rustc_query_impl[eb95ff51c492efdd]::queries::analysis, rustc_query_impl[eb95ff51c492efdd]::plumbing::QueryCtxt>
  39:     0x7fd227f81740 - <rustc_query_impl[eb95ff51c492efdd]::Queries as rustc_middle[eaae5d2a0b8f0144]::ty::query::QueryEngine>::analysis
  40:     0x7fd227daa789 - <rustc_middle[eaae5d2a0b8f0144]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>
  41:     0x7fd227999f08 - rustc_span[18b84908941c7cdf]::with_source_map::<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  42:     0x7fd22799116c - std[1337fb43929788f1]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[ceda1fd77ec39e1b]::util::run_in_thread_pool_with_globals<rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>
  43:     0x7fd227990b9a - <<std[1337fb43929788f1]::thread::Builder>::spawn_unchecked_<rustc_interface[ceda1fd77ec39e1b]::util::run_in_thread_pool_with_globals<rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#1} as core[2011dc7817943e09]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  44:     0x7fd22542d793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h7e0474dd3b8659fa
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:1988:9
  45:     0x7fd22542d793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::heb8c41cf543a5c11
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:1988:9
  46:     0x7fd22542d793 - std::sys::unix::thread::Thread::new::thread_start::hc791abe67253fe06
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys/unix/thread.rs:108:17
  47:     0x7fd2252f9d40 - start_thread
  48:     0x7fd22521603f - __GI___clone
  49:                0x0 - <unknown>

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 1.70.0-nightly (22f247c6f 2023-03-13) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib

query stack during panic:
#0 [check_mod_attrs] checking attributes in top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors; 1 warning emitted

[compiler-errors]

This happens on the same line as in these issues; though with a different query stack.

For future reference, this generally suggests that this is a totally unrelated issue.

[compiler-errors]

To be a bit clearer with that last message, there are a few ICEs that commonly crop up in the compiler with similar "leaf" causes but different root causes. Anything having to do with snapshot_vec, to give another example, is probably unique.

[matthiaskrgr]

Anything having to do with snapshot_vec, to give another example, is probably unique.

👀