ICE: `unexpected infer type`

[matthiaskrgr]

auto-reduced (treereduce-rust):

trait Project {
    const SELF: Self;
}

fn take1(_: Project<SELF = { loop {} }>) {}

original code

original:

// Regression test for issue #108271.
// Detect and reject generic params in the type of assoc consts used in an equality bound.
#![feature(associated_const_equality)]

trait Trait<'a, T: 'a, const N: usize> {
    //~^ NOTE the lifetime parameter `'r` is defined here
    //~| NOTE the lifetime parameter `'r` is defined here
    type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    //~^ ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the lifetime parameter `'r`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on `Self`
    //~| NOTE its type must not depend on `Self`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the const parameter `Q`
    //~| NOTE the const parameter `Q` is defined here
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| NOTE its type must not depend on the lifetime parameter `'r`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on `Self`
    //~| NOTE its type must not depend on `Self`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the const parameter `Q`
    //~| NOTE the const parameter `Q` is defined here
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
    where
        Self: Sized + 'r;
}

fn take0<'r, A: Project<SELF = {}>, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
//~^ ERROR the type of the associated constant `K` must not depend on generic parameters
//~| NOTE its type must not depend on the lifetime parameter `'r`
//~| NOTE the lifetime parameter `'r` is defined here
//~^ ERROR the type of the associated constant `K` must not depend on generic parameters
//~| ERROR the type of the associated constant `K` must not depend on generic parameters
//~| NOTE its type must not depend on the type parameter `A`
//~| NOTE the type parameter `A` is defined here
//~| NOTE `K` has type `&'r [A; Q]`
//~| ERROR the type of the associated constant `K` must not depend on generic parameters
//~| NOTE its type must not depend on the const parameter `Q`
//~| NOTE the const parameter `Q` is defined here
//~| NOTE `K` has type `&'r [A; Q]`

trait Project {
    const SELF: Self;
}

fn take1(_:  Project<SELF = { loop {} }>) {}
//~^ ERROR the type of the associated constant `SELF` must not depend on `impl Trait`
//~| NOTE its type must not depend on `impl Trait`
//~| NOTE the `impl Trait` is specified here

fn take2<P: Project<SELF = {}>>(_: P) {}
//~^ ERROR the type of the associated constant `SELF` must not depend on generic parameters
//~| NOTE its type must not depend on the type parameter `P`
//~| NOTE the type parameter `P` is defined here
//~| NOTE `SELF` has type `P`

trait Iface<'r> {
    //~^ NOTE the lifetime parameter `'r` is defined here
    //~| NOTE the lifetime parameter `'r` is defined here
    type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    //~^ ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the lifetime parameter `'r`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on `Self`
    //~| NOTE its type must not depend on `Self`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the const parameter `Q`
    //~| NOTE the const parameter `Q` is defined here
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| NOTE its type must not depend on the lifetime parameter `'r`
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on `Self`
    //~| NOTE its type must not depend on `Self`
    //~| NOTE `K` has type `&'r [A; Q]`
    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
    //~| NOTE its type must not depend on the const parameter `Q`
    //~| NOTE the const parameter `Q` is defined here
    //~| NOTE `K` has type `&'r [Self; Q]`
    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
    //~^ ERROR the type of the associated constant `SELF` must not depend on generic parameters
    //~| NOTE its type must not depend on `Self`
    SELF =;
}

fn main() { loop {} }

Version information

rustc 1.79.0-nightly (d5db7fb53 2024-03-27)
binary: rustc
commit-hash: d5db7fb537c0352eec3855aa0331c271c48ac4f6
commit-date: 2024-03-27
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.2

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

Program output

error[E0658]: associated const equality is incomplete
 --> /tmp/icemaker_global_tempdir.iaTnhD6gpiUs/rustc_testrunner_tmpdir_reporting.j6t1MTYnJCzk/mvce.rs:5:21
  |
5 | fn take1(_: Project<SELF = { loop {} }>) {}
  |                     ^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #92827 <https://github.com/rust-lang/rust/issues/92827> for more information
  = help: add `#![feature(associated_const_equality)]` to the crate attributes to enable
  = note: this compiler was built on 2024-03-27; consider upgrading it if it is out of date

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.iaTnhD6gpiUs/rustc_testrunner_tmpdir_reporting.j6t1MTYnJCzk/mvce.rs:5:44
  |
5 | fn take1(_: Project<SELF = { loop {} }>) {}
  |                                            ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.iaTnhD6gpiUs/rustc_testrunner_tmpdir_reporting.j6t1MTYnJCzk/mvce.rs`

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.iaTnhD6gpiUs/rustc_testrunner_tmpdir_reporting.j6t1MTYnJCzk/mvce.rs:5:13
  |
5 | fn take1(_: Project<SELF = { loop {} }>) {}
  |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
  = note: `#[warn(bare_trait_objects)]` on by default
help: if this is an object-safe trait, use `dyn`
  |
5 | fn take1(_: dyn Project<SELF = { loop {} }>) {}
  |             +++

error: internal compiler error: compiler/rustc_infer/src/infer/relate/generalize.rs:458:17: unexpected infer type: FreshTy(0)

thread 'rustc' panicked at compiler/rustc_infer/src/infer/relate/generalize.rs:458:17:
Box<dyn Any>
stack backtrace:
   0:     0x7a1979cc4235 - std::backtrace_rs::backtrace::libunwind::trace::h35c05b60de86c082
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7a1979cc4235 - std::backtrace_rs::backtrace::trace_unsynchronized::h716cc93b6616466b
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7a1979cc4235 - std::sys_common::backtrace::_print_fmt::h2eafab78e5405086
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7a1979cc4235 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h782eb93aef6bbfdc
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7a1979d153fb - core::fmt::rt::Argument::fmt::h423c1825313972bd
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/core/src/fmt/rt.rs:142:9
   5:     0x7a1979d153fb - core::fmt::write::h8bf0eb0713660507
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/core/src/fmt/mod.rs:1153:17
   6:     0x7a1979cb8e4f - std::io::Write::write_fmt::h1869b88304121496
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/io/mod.rs:1843:15
   7:     0x7a1979cc400e - std::sys_common::backtrace::_print::h3f71a60e8eec22db
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7a1979cc400e - std::sys_common::backtrace::print::hbc0f4a4435261b96
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7a1979cc6c89 - std::panicking::default_hook::{{closure}}::hcb90344a23466037
  10:     0x7a1979cc69f3 - std::panicking::default_hook::h4e7402b852825f26
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/panicking.rs:292:9
  11:     0x7a19765f7eee - std[ee38f4c3e7db4cb4]::panicking::update_hook::<alloc[5f51a9fa993ddee8]::boxed::Box<rustc_driver_impl[b62da54691605f75]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7a1979cc738c - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h41b4c40829d8b80c
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/alloc/src/boxed.rs:2032:9
  13:     0x7a1979cc738c - std::panicking::rust_panic_with_hook::h34319b28877d2524
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/panicking.rs:793:13
  14:     0x7a1976627d64 - std[ee38f4c3e7db4cb4]::panicking::begin_panic::<rustc_errors[82d4239d9c7af4ff]::ExplicitBug>::{closure#0}
  15:     0x7a1976624c86 - std[ee38f4c3e7db4cb4]::sys_common::backtrace::__rust_end_short_backtrace::<std[ee38f4c3e7db4cb4]::panicking::begin_panic<rustc_errors[82d4239d9c7af4ff]::ExplicitBug>::{closure#0}, !>
  16:     0x7a1976624966 - std[ee38f4c3e7db4cb4]::panicking::begin_panic::<rustc_errors[82d4239d9c7af4ff]::ExplicitBug>
  17:     0x7a19766311f1 - <rustc_errors[82d4239d9c7af4ff]::diagnostic::BugAbort as rustc_errors[82d4239d9c7af4ff]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7a1976ac17bc - rustc_middle[edfcb02b6a244f2]::util::bug::opt_span_bug_fmt::<rustc_span[b9a3f8dff5ad8c72]::span_encoding::Span>::{closure#0}
  19:     0x7a1976aa52ba - rustc_middle[edfcb02b6a244f2]::ty::context::tls::with_opt::<rustc_middle[edfcb02b6a244f2]::util::bug::opt_span_bug_fmt<rustc_span[b9a3f8dff5ad8c72]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x7a1976aa515b - rustc_middle[edfcb02b6a244f2]::ty::context::tls::with_context_opt::<rustc_middle[edfcb02b6a244f2]::ty::context::tls::with_opt<rustc_middle[edfcb02b6a244f2]::util::bug::opt_span_bug_fmt<rustc_span[b9a3f8dff5ad8c72]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x7a1974703930 - rustc_middle[edfcb02b6a244f2]::util::bug::bug_fmt
  22:     0x7a1977aa5b28 - <rustc_infer[db4fc5bbfe73a864]::infer::relate::generalize::Generalizer as rustc_middle[edfcb02b6a244f2]::ty::relate::TypeRelation>::tys
  23:     0x7a1977a9116a - <rustc_infer[db4fc5bbfe73a864]::infer::relate::type_relating::TypeRelating as rustc_middle[edfcb02b6a244f2]::ty::relate::TypeRelation>::tys
  24:     0x7a1977a836c3 - <rustc_hir_typeck[d5655f81daec17bc]::fn_ctxt::FnCtxt>::coerce
  25:     0x7a1977a721ab - <rustc_hir_typeck[d5655f81daec17bc]::fn_ctxt::FnCtxt>::demand_coerce
  26:     0x7a1977bf594d - rustc_hir_typeck[d5655f81daec17bc]::typeck
  27:     0x7a1977bf3a57 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>
  28:     0x7a1977be0971 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  29:     0x7a1977bdcdcc - rustc_query_impl[2d2f12ae863522a2]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7a1977dcb79c - rustc_mir_build[1b46b2c93e920ce6]::thir::pattern::check_match::check_match
  31:     0x7a1977dca93b - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::check_match::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>
  32:     0x7a197813bd7c - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  33:     0x7a197813b9ff - rustc_query_impl[2d2f12ae863522a2]::query_impl::check_match::get_query_non_incr::__rust_end_short_backtrace
  34:     0x7a1977dba5f3 - rustc_mir_build[1b46b2c93e920ce6]::build::mir_build
  35:     0x7a1977db9aa8 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_built::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>
  36:     0x7a1977be0971 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  37:     0x7a1977be054c - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace
  38:     0x7a1977be024b - rustc_middle[edfcb02b6a244f2]::query::plumbing::query_get_at::<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>>
  39:     0x7a197812f701 - rustc_mir_transform[953c3acd5e2981a0]::mir_const_qualif
  40:     0x7a197812f6b5 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_const_qualif::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 4usize]>>
  41:     0x7a197812f18b - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::DefIdCache<rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 4usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  42:     0x7a197812ef09 - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_const_qualif::get_query_non_incr::__rust_end_short_backtrace
  43:     0x7a197812ed36 - rustc_middle[edfcb02b6a244f2]::query::plumbing::query_get_at::<rustc_query_system[1181c72fefabd0ae]::query::caches::DefIdCache<rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 4usize]>>>
  44:     0x7a1974f714b6 - rustc_mir_transform[953c3acd5e2981a0]::mir_promoted
  45:     0x7a1977d0341c - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_promoted::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 16usize]>>
  46:     0x7a1977d036ed - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  47:     0x7a1977d03325 - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_promoted::get_query_non_incr::__rust_end_short_backtrace
  48:     0x7a1977bdead0 - rustc_borrowck[87c1aa11a50066c]::mir_borrowck
  49:     0x7a1977bdea17 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>
  50:     0x7a1977be0971 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  51:     0x7a1977be048c - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  52:     0x7a1978136aab - rustc_mir_transform[953c3acd5e2981a0]::mir_drops_elaborated_and_const_checked
  53:     0x7a19781361a5 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>
  54:     0x7a1977be0971 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  55:     0x7a1977be030c - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  56:     0x7a1977be024b - rustc_middle[edfcb02b6a244f2]::query::plumbing::query_get_at::<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>>
  57:     0x7a1978134f6c - rustc_mir_transform[953c3acd5e2981a0]::mir_for_ctfe
  58:     0x7a1978134edb - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_for_ctfe::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>
  59:     0x7a1977bc6f9c - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::DefIdCache<rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  60:     0x7a19785b049e - rustc_query_impl[2d2f12ae863522a2]::query_impl::mir_for_ctfe::get_query_non_incr::__rust_end_short_backtrace
  61:     0x7a19785b07ca - <rustc_const_eval[176732e30479c26b]::interpret::eval_context::InterpCx<rustc_const_eval[176732e30479c26b]::const_eval::machine::CompileTimeInterpreter>>::load_mir
  62:     0x7a19785b25df - rustc_const_eval[176732e30479c26b]::const_eval::eval_queries::eval_to_allocation_raw_provider
  63:     0x7a19785b2340 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>
  64:     0x7a19785af396 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::DefaultCache<rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  65:     0x7a19785aef6c - rustc_query_impl[2d2f12ae863522a2]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  66:     0x7a19785aeb0a - rustc_middle[edfcb02b6a244f2]::query::plumbing::query_get_at::<rustc_query_system[1181c72fefabd0ae]::query::caches::DefaultCache<rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>>
  67:     0x7a197858c421 - rustc_const_eval[176732e30479c26b]::const_eval::valtrees::eval_to_valtree
  68:     0x7a197858c3a2 - <rustc_const_eval[176732e30479c26b]::provide::{closure#0} as core[852c89a24d64efc7]::ops::function::FnOnce<(rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt, rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>)>>::call_once
  69:     0x7a197858c376 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::eval_to_valtree::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>
  70:     0x7a197858c32f - <rustc_query_impl[2d2f12ae863522a2]::query_impl::eval_to_valtree::dynamic_query::{closure#2} as core[852c89a24d64efc7]::ops::function::FnOnce<(rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt, rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>)>>::call_once
  71:     0x7a19785af471 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::DefaultCache<rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  72:     0x7a19785999ac - rustc_query_impl[2d2f12ae863522a2]::query_impl::eval_to_valtree::get_query_non_incr::__rust_end_short_backtrace
  73:     0x7a1977d3e847 - rustc_middle[edfcb02b6a244f2]::query::plumbing::query_get_at::<rustc_query_system[1181c72fefabd0ae]::query::caches::DefaultCache<rustc_middle[edfcb02b6a244f2]::ty::ParamEnvAnd<rustc_middle[edfcb02b6a244f2]::mir::interpret::GlobalId>, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 24usize]>>>
  74:     0x7a19782b791c - <rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt>::const_eval_global_id_for_typeck
  75:     0x7a19782b70a1 - <rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt>::const_eval_resolve_for_typeck
  76:     0x7a19782b6e56 - <rustc_middle[edfcb02b6a244f2]::ty::consts::Const>::eval
  77:     0x7a1977bf07c1 - <rustc_trait_selection[44f63119e1d12199]::traits::normalize::AssocTypeNormalizer as rustc_type_ir[4b4d295dba5e89f3]::fold::TypeFolder<rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt>>::fold_const
  78:     0x7a19770f6dcd - <rustc_trait_selection[44f63119e1d12199]::traits::normalize::AssocTypeNormalizer as rustc_type_ir[4b4d295dba5e89f3]::fold::TypeFolder<rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt>>::fold_binder::<rustc_middle[edfcb02b6a244f2]::ty::predicate::ExistentialPredicate>
  79:     0x7a19781fb427 - <rustc_middle[edfcb02b6a244f2]::ty::Ty as rustc_type_ir[4b4d295dba5e89f3]::fold::TypeSuperFoldable<rustc_middle[edfcb02b6a244f2]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection[44f63119e1d12199]::traits::normalize::AssocTypeNormalizer>
  80:     0x7a19780605ec - <rustc_hir_analysis[9a86bb4861b99e0a]::check::wfcheck::WfCheckingCtxt>::normalize::<rustc_middle[edfcb02b6a244f2]::ty::Ty>
  81:     0x7a197806140b - rustc_hir_analysis[9a86bb4861b99e0a]::check::wfcheck::check_fn_or_method
  82:     0x7a197805f28f - rustc_hir_analysis[9a86bb4861b99e0a]::check::wfcheck::check_item_fn
  83:     0x7a197806fec5 - rustc_hir_analysis[9a86bb4861b99e0a]::check::wfcheck::check_well_formed
  84:     0x7a197806e787 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>
  85:     0x7a197806df00 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::VecCache<rustc_hir[7cb6db536684f817]::hir_id::OwnerId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  86:     0x7a197806dc7f - rustc_query_impl[2d2f12ae863522a2]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  87:     0x7a197806bbc6 - rustc_hir_analysis[9a86bb4861b99e0a]::check::wfcheck::check_mod_type_wf
  88:     0x7a197806ba09 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>
  89:     0x7a197849e830 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::DefaultCache<rustc_span[b9a3f8dff5ad8c72]::def_id::LocalModDefId, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  90:     0x7a197849e5db - rustc_query_impl[2d2f12ae863522a2]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  91:     0x7a1977bdb07b - rustc_hir_analysis[9a86bb4861b99e0a]::check_crate
  92:     0x7a1977f4aaea - rustc_interface[8a3ca12de370bc6d]::passes::analysis
  93:     0x7a1977f4a659 - rustc_query_impl[2d2f12ae863522a2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d2f12ae863522a2]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>
  94:     0x7a1978794da5 - rustc_query_system[1181c72fefabd0ae]::query::plumbing::try_execute_query::<rustc_query_impl[2d2f12ae863522a2]::DynamicConfig<rustc_query_system[1181c72fefabd0ae]::query::caches::SingleCache<rustc_middle[edfcb02b6a244f2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[2d2f12ae863522a2]::plumbing::QueryCtxt, false>
  95:     0x7a1978794b09 - rustc_query_impl[2d2f12ae863522a2]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  96:     0x7a1978687299 - rustc_interface[8a3ca12de370bc6d]::interface::run_compiler::<core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>, rustc_driver_impl[b62da54691605f75]::run_compiler::{closure#0}>::{closure#0}
  97:     0x7a19787665e3 - std[ee38f4c3e7db4cb4]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[8a3ca12de370bc6d]::util::run_in_thread_with_globals<rustc_interface[8a3ca12de370bc6d]::util::run_in_thread_pool_with_globals<rustc_interface[8a3ca12de370bc6d]::interface::run_compiler<core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>, rustc_driver_impl[b62da54691605f75]::run_compiler::{closure#0}>::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>
  98:     0x7a1978766410 - <<std[ee38f4c3e7db4cb4]::thread::Builder>::spawn_unchecked_<rustc_interface[8a3ca12de370bc6d]::util::run_in_thread_with_globals<rustc_interface[8a3ca12de370bc6d]::util::run_in_thread_pool_with_globals<rustc_interface[8a3ca12de370bc6d]::interface::run_compiler<core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>, rustc_driver_impl[b62da54691605f75]::run_compiler::{closure#0}>::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[852c89a24d64efc7]::result::Result<(), rustc_span[b9a3f8dff5ad8c72]::ErrorGuaranteed>>::{closure#1} as core[852c89a24d64efc7]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  99:     0x7a1979cd0ca9 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hc7f4be48b61584a0
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/alloc/src/boxed.rs:2018:9
 100:     0x7a1979cd0ca9 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h98f2eb6153ee7231
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/alloc/src/boxed.rs:2018:9
 101:     0x7a1979cd0ca9 - std::sys::pal::unix::thread::Thread::new::thread_start::h5b05a8117b189654
                               at /rustc/d5db7fb537c0352eec3855aa0331c271c48ac4f6/library/std/src/sys/pal/unix/thread.rs:108:17
 102:     0x7a19734a955a - <unknown>
 103:     0x7a1973526a3c - <unknown>
 104:                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 1.79.0-nightly (d5db7fb53 2024-03-27) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `take1::{constant#0}`
#1 [check_match] match-checking `take1::{constant#0}`
#2 [mir_built] building MIR for `take1::{constant#0}`
#3 [mir_const_qualif] const checking `take1::{constant#0}`
#4 [mir_promoted] promoting constants in MIR for `take1::{constant#0}`
#5 [mir_borrowck] borrow-checking `take1::{constant#0}`
#6 [mir_drops_elaborated_and_const_checked] elaborating drops for `take1::{constant#0}`
#7 [mir_for_ctfe] caching mir of `take1::{constant#0}` for CTFE
#8 [eval_to_allocation_raw] const-evaluating + checking `take1::{constant#0}`
#9 [eval_to_valtree] evaluating type-level constant
#10 [check_well_formed] checking that `take1` is well-formed
#11 [check_mod_type_wf] checking that types are well-formed in top-level module
#12 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors; 1 warning emitted

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

[matthiaskrgr]

Regression in nightly-2023-02-18

looking for regression commit between 2023-02-17 and 2023-02-18
fetching (via remote github) commits from max(9a7cc6c, 2023-02-15) to 9aa5c24
ending github query because we found starting sha: 9a7cc6c
get_commits_between returning commits, len: 8
commit[0] 2023-02-16: Auto merge of #108127 - matthiaskrgr:rollup-kpzfc6j, r=matthiaskrgr
commit[1] 2023-02-16: Auto merge of #107833 - Zoxc:arena-query-clean, r=cjgillot
commit[2] 2023-02-17: Auto merge of #108145 - matthiaskrgr:rollup-bgadak1, r=matthiaskrgr
commit[3] 2023-02-17: Auto merge of #107753 - kylematsuda:type-of, r=BoxyUwU
commit[4] 2023-02-17: Auto merge of #108058 - Zoxc:query-ctxtx-byval, r=cjgillot
commit[5] 2023-02-17: Auto merge of #107965 - BoxyUwU:add_const_arg_has_type_predicate, r=compiler-errors
commit[6] 2023-02-17: Auto merge of #108159 - matthiaskrgr:rollup-5k2j7cx, r=matthiaskrgr
commit[7] 2023-02-17: Auto merge of #108075 - WaffleLapkin:de-arena-allocates-you-OwO, r=Nilstrieb
ERROR: no CI builds available between 9a7cc6c and 9aa5c24 within last 167 days

[fmease]

Oh, I see. I forgot about tcx.types.trait_object_dummy_self (FreshTy(0)) in #121258. Ofc, my PR doesn't regress anything here but still I forgot about this case. Very likely we need to reject trait_object_dummy_self manually and can't rely on registering a <Ty as core::marker::ConstParamTy> obligation¹ (which I plan to do to fix #119783 but the location is still unclear to me²) because we just shouldn't be feeding the fake FreshTy(0) to type_of as can be seen by the ICE, the trait solver & the inference engine obviously can't handle such malformed obligations.

Footnotes

1. Trait object types never impl ConstParamTy. ↩

2. HIR wf-checking isn't an option because we lack too much information at this stage, during normalization isn't an option since we shouldn't rely on normalization for ensuring well-formedness, leaving us with constructing an ObligationCtxt ad hoc during HIR ty lowering which isn't super great. ↩

[fmease]

Wait, I don't think we should deny trait_object_dummy_self in the code path that rejects early-bound and escaping late-bound vars, that's not the right thing to do. They are semi-legitimate types that get discarded by helpers like ExistentialTraitRef::erase_self_ty and ExistentialProjection::erase_self_ty, e.g. inside lower_trait_object_ty (which also introduces these dummy_self types).

Oh, okay, so inside lower_trait_object_ty we discard const projections if their args contain a dummy self type but in our case, the projected type (the type_of(proj)) contains a dummy self type.

As the comment over there says such a (const) projection would expand to an infinitely-long type. We also need to check the projected type for dummy self types and drop the existential const projection in case we find any. Edit: Tho, no I'm confused since the projection_ty and the term.ct().ty() should be same in this case due to the anon const feeding, so why isn't it detecting anything? 🤔 Update: We don't even reach the aforementioned branch inside lower_trait_object_ty for some reason. Update: Oh, that's not the code path we're interested in, that's only for super trait elab.

[fmease]

Stopping my investigations for now but overwriting the args (incl. the self type subst) of such projections with {type error} as well turning the const projection term into {const error} if the args or the type of the projected const contains trait_object_dummy_self didn't help. Note that lower_trait_object_ty does parts of this already.

I haven't dug deeper yet but the cause of this might be the anon const query feeding in lower_assoc_item_binding: We may feed trait_object_dummy_self to type_of(AnonConst) which can't be undone.