ICE: 🌲 not implemented: NormalizationFailure(Alias(Projection, AliasTy...

[matthiaskrgr]

auto-reduced (treereduce-rust):

trait Xxx {}

trait Yyy: Xxx {}

trait Aaa {
    type Y: Yyy;
}

trait Bbb {
    type B: for<'a> std::mem::TransmuteFrom<(), ()>;
}

impl<T> Bbb for T
where
    T: Aaa,
    _9F::Y:,
{
    type B = T::Y;
}

original:

trait Www {
    type W;
}

trait Xxx: Www<W = Self::X> {
    type X;
}

trait Yyy: Xxx {}

trait Zzz<'a>: Yyy + Xxx<X = Self::Z> {
    type Z;
}

trait Aaa {
    type Y: Yyy;
}

trait Bbb: Aaa<Y = Self::B> {
    type B: for<'a> std::mem::TransmuteFrom<(), ()>;
}

impl<T> Bbb for T
where
    T: Aaa,
    _9F::Y: for<'a> Zzz<'t>,
{
    type B = T::Y;
}

pub fn main() {}

Version information

rustc 1.83.0-nightly (8c2c9a9ef 2024-09-15)
binary: rustc
commit-hash: 8c2c9a9ef527edb453bcee638d34beb0e7b4616b
commit-date: 2024-09-15
host: x86_64-unknown-linux-gnu
release: 1.83.0-nightly
LLVM version: 19.1.0

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs:19:2
   |
19 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs`

error[E0658]: use of unstable library feature 'transmutability'
  --> /tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs:10:21
   |
10 |     type B: for<'a> std::mem::TransmuteFrom<(), ()>;
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #99571 <https://github.com/rust-lang/rust/issues/99571> for more information
   = help: add `#![feature(transmutability)]` to the crate attributes to enable
   = note: this compiler was built on 2024-09-15; consider upgrading it if it is out of date

error[E0747]: type provided when a constant was expected
  --> /tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs:10:49
   |
10 |     type B: for<'a> std::mem::TransmuteFrom<(), ()>;
   |                                                 ^^

thread 'rustc' panicked at compiler/rustc_transmute/src/layout/tree.rs:201:24:
not implemented: NormalizationFailure(Alias(Projection, AliasTy { args: [T/#0], def_id: DefId(0:6 ~ mvce[023b]::Aaa::Y), .. }), Type(Alias(Projection, AliasTy { args: [T/#0], def_id: DefId(0:6 ~ mvce[023b]::Aaa::Y), .. })))
stack backtrace:
   0:     0x711b5d46c1da - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hf576e3db34dcd4c0
   1:     0x711b5dc03297 - core::fmt::write::h6031a1fcd647db63
   2:     0x711b5eb10373 - std::io::Write::write_fmt::h9c4d18eebfa610c9
   3:     0x711b5d46c032 - std::sys::backtrace::BacktraceLock::print::hd5d6f94195a58c57
   4:     0x711b5d46e7b1 - std::panicking::default_hook::{{closure}}::he12b6c1c70a494ea
   5:     0x711b5d46e5e4 - std::panicking::default_hook::h79139f377ef49e73
   6:     0x711b5c57090f - std[1fc20c4bf4345a88]::panicking::update_hook::<alloc[31ea272c46cb0a00]::boxed::Box<rustc_driver_impl[bd499d3fdd772cd8]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x711b5d46eed8 - std::panicking::rust_panic_with_hook::hb2e822dcfa6f992d
   8:     0x711b5d46eca7 - std::panicking::begin_panic_handler::{{closure}}::h009211ca5b32b3da
   9:     0x711b5d46c689 - std::sys::backtrace::__rust_end_short_backtrace::h3f6b2521411fe228
  10:     0x711b5d46e974 - rust_begin_unwind
  11:     0x711b5a293d23 - core::panicking::panic_fmt::hfae13f2be10fd19a
  12:     0x711b5d3aad20 - <rustc_transmute[68be87005f1b188a]::layout::tree::rustc::Err as core[72d89f67a2ed16cb]::convert::From<&rustc_middle[75f727fe079a4f22]::ty::layout::LayoutError>>::from
  13:     0x711b5d3aaea4 - <rustc_transmute[68be87005f1b188a]::layout::tree::Tree<rustc_transmute[68be87005f1b188a]::layout::rustc::Def, rustc_transmute[68be87005f1b188a]::layout::rustc::Ref>>::from_ty
  14:     0x711b5d3afd0a - <rustc_transmute[68be87005f1b188a]::rustc::TransmuteTypeEnv>::is_transmutable
  15:     0x711b5d2b5111 - <rustc_trait_selection[fd550b6f72b0e0c6]::error_reporting::TypeErrCtxt>::get_safe_transmute_error_and_reason
  16:     0x711b5d2a7b61 - <rustc_trait_selection[fd550b6f72b0e0c6]::error_reporting::TypeErrCtxt>::report_selection_error
  17:     0x711b5d325d5b - <rustc_trait_selection[fd550b6f72b0e0c6]::error_reporting::TypeErrCtxt>::report_fulfillment_error
  18:     0x711b5d2ee2b7 - <rustc_trait_selection[fd550b6f72b0e0c6]::error_reporting::TypeErrCtxt>::report_fulfillment_errors
  19:     0x711b5e26b4e6 - rustc_hir_analysis[f9d0127424903d94]::check::compare_impl_item::check_type_bounds
  20:     0x711b5a055544 - rustc_hir_analysis[f9d0127424903d94]::check::check::check_impl_items_against_trait
  21:     0x711b5b337482 - rustc_hir_analysis[f9d0127424903d94]::check::wfcheck::check_well_formed
  22:     0x711b5e11a3c7 - rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>
  23:     0x711b5e11a63e - rustc_query_system[5ff4688cf420f9ff]::query::plumbing::try_execute_query::<rustc_query_impl[85a0e4e3d1ea5e51]::DynamicConfig<rustc_query_system[5ff4688cf420f9ff]::query::caches::VecCache<rustc_hir[bda7baf23f46ef3e]::hir_id::OwnerId, rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::QueryCtxt, false>
  24:     0x711b5e11a3a2 - rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  25:     0x711b5e11b153 - rustc_hir_analysis[f9d0127424903d94]::check::wfcheck::check_mod_type_wf
  26:     0x711b5e11af91 - rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>
  27:     0x711b5eaaa5bb - rustc_query_system[5ff4688cf420f9ff]::query::plumbing::try_execute_query::<rustc_query_impl[85a0e4e3d1ea5e51]::DynamicConfig<rustc_query_system[5ff4688cf420f9ff]::query::caches::DefaultCache<rustc_span[a0fd5433b72e73f5]::def_id::LocalModDefId, rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::QueryCtxt, false>
  28:     0x711b5eaaa36d - rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  29:     0x711b5e073a49 - rustc_hir_analysis[f9d0127424903d94]::check_crate
  30:     0x711b5e070705 - rustc_interface[21c67170a9071fc5]::passes::run_required_analyses
  31:     0x711b5e9166de - rustc_interface[21c67170a9071fc5]::passes::analysis
  32:     0x711b5e9166b1 - rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>
  33:     0x711b5eaae22e - rustc_query_system[5ff4688cf420f9ff]::query::plumbing::try_execute_query::<rustc_query_impl[85a0e4e3d1ea5e51]::DynamicConfig<rustc_query_system[5ff4688cf420f9ff]::query::caches::SingleCache<rustc_middle[75f727fe079a4f22]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[85a0e4e3d1ea5e51]::plumbing::QueryCtxt, false>
  34:     0x711b5eaadf8f - rustc_query_impl[85a0e4e3d1ea5e51]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  35:     0x711b5e900bbc - rustc_interface[21c67170a9071fc5]::interface::run_compiler::<core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>, rustc_driver_impl[bd499d3fdd772cd8]::run_compiler::{closure#0}>::{closure#1}
  36:     0x711b5e9c8850 - std[1fc20c4bf4345a88]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[21c67170a9071fc5]::util::run_in_thread_with_globals<rustc_interface[21c67170a9071fc5]::util::run_in_thread_pool_with_globals<rustc_interface[21c67170a9071fc5]::interface::run_compiler<core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>, rustc_driver_impl[bd499d3fdd772cd8]::run_compiler::{closure#0}>::{closure#1}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>::{closure#0}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>
  37:     0x711b5e9c8eba - <<std[1fc20c4bf4345a88]::thread::Builder>::spawn_unchecked_<rustc_interface[21c67170a9071fc5]::util::run_in_thread_with_globals<rustc_interface[21c67170a9071fc5]::util::run_in_thread_pool_with_globals<rustc_interface[21c67170a9071fc5]::interface::run_compiler<core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>, rustc_driver_impl[bd499d3fdd772cd8]::run_compiler::{closure#0}>::{closure#1}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>::{closure#0}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[72d89f67a2ed16cb]::result::Result<(), rustc_span[a0fd5433b72e73f5]::ErrorGuaranteed>>::{closure#1} as core[72d89f67a2ed16cb]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  38:     0x711b5e9c92ab - std::sys::pal::unix::thread::Thread::new::thread_start::hfd4e0f9214174c65
  39:     0x711b601ef39d - <unknown>
  40:     0x711b6027449c - <unknown>
  41:                0x0 - <unknown>

error: 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: please make sure that you have updated to the latest nightly

note: rustc 1.83.0-nightly (8c2c9a9ef 2024-09-15) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [check_well_formed] checking that `<impl at /tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs:13:1: 16:13>` is well-formed
#1 [check_mod_type_wf] checking that types are well-formed in top-level module
end of query stack
error[E0433]: failed to resolve: use of undeclared crate or module `_9F`
  --> /tmp/icemaker_global_tempdir.R0GRNNzkiwFC/rustc_testrunner_tmpdir_reporting.Cp4fKl735t3r/mvce.rs:16:5
   |
16 |     _9F::Y:,
   |     ^^^ use of undeclared crate or module `_9F`

error: aborting due to 4 previous errors

Some errors have detailed explanations: E0433, E0601, E0658, E0747.
For more information about an error, try `rustc --explain E0433`.

[matthiaskrgr]

Regression in nightly-2024-08-22
seems to bisect to #129364

[cyrgani]

Slightly more reduction:

#![feature(transmutability)]
trait Aaa {
    type Y;
}

trait Bbb {
    type B: std::mem::TransmuteFrom<()>;
}

impl<T> Bbb for T
where
    T: Aaa,
{
    type B = T::Y;
}

[jieyouxu]

Slightly more reduction:

(Note that this reduction should drop the feature gate, as this ICEs without the feature gate)

[jswrenn]

@rustbot claim