regression: ICE: Failed to normalize Alias(Opaque, AliasTy

[BoxyUwU]

• https://crater-reports.s3.amazonaws.com/beta-1.85-1/beta-2025-01-12/gh/Menestis.Skynet/log.txt

[INFO] [stdout] error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:168:90: Failed to normalize Alias(Opaque, AliasTy { args: [], def_id: DefId(0:850 ~ skynet[716d]::web::create_task::{opaque#0}::{opaque#0}), .. }), maybe try to call `try_normalize_erasing_regions` instead

[theemathas]

Somewhat minimized (zipped for your convenience: repro.zip):

src/lib.rs

use std::future::Future;

use warp::{Filter, Rejection, Reply};

pub async fn foo() {
    let _ = create_task().await;
}

// Note: This is an async function that also returns a future.
async fn create_task() -> impl Future<Output = ()> {
    warp::serve(warp::get().and_then(documentation)).bind(([127, 0, 0, 1], 8888))
}

async fn documentation() -> Result<impl Reply, Rejection> {
    include_str!("nonexistent");
    Ok("")
}

Cargo.toml

[package]
name = "skynet"
version = "0.1.0"
edition = "2021"

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warp = { version = "0.3.2", default-features = false }

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source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"

[[package]]
name = "winapi-x86_64-pc-windows-gnu"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

[theemathas]

Minimized:

use std::future::Future;

pub async fn foo() {
    let _ = create_task().await;
}

async fn create_task() -> impl Sized {
    bind(documentation)
}

async fn documentation() {
    include_str!("nonexistent");
}

fn bind<F>(_filter: F) -> impl Sized
where
    F: FilterBase,
{
    || -> <F as FilterBase>::Assoc { panic!() }
}

trait FilterBase {
    type Assoc;
}

impl<F, R> FilterBase for F
where
    F: Fn() -> R,
    // Removing the below line makes it correctly error on both stable and beta
    R: Future,
    // Removing the below line makes it ICE on both stable and beta
    R: Send,
    // Removing the above two bounds makes it ICE on stable but correctly error on beta
{
    type Assoc = F;
}

The above code correctly produces an error with cargo +stable build, but produces an ICE with cargo +beta build.

Error output

error: couldn't read `src/nonexistent`: No such file or directory (os error 2)
  --> src/lib.rs:12:5
   |
12 |     include_str!("nonexistent");
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)

error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:168:90: Failed to normalize Alias(Opaque, AliasTy { args: [], def_id: DefId(0:9 ~ playground[a52f]::create_task::{opaque#0}::{opaque#0}), .. }), maybe try to call `try_normalize_erasing_regions` instead


thread 'rustc' panicked at compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:168:90:
Box<dyn Any>
stack backtrace:
   0:     0x721839ee35ca - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h9fe8706f0b7b60e6
   1:     0x72183a6135e6 - core::fmt::write::h8ad1c8502cd006f5
   2:     0x72183b51dd51 - std::io::Write::write_fmt::h89d7067e8130387a
   3:     0x721839ee3422 - std::sys::backtrace::BacktraceLock::print::h2604f7f483ba81db
   4:     0x721839ee59c7 - std::panicking::default_hook::{{closure}}::h980e999aca8eb276
   5:     0x721839ee57b0 - std::panicking::default_hook::h807fe813e668e0ef
   6:     0x721839057218 - std[604c1f9fe749a3ed]::panicking::update_hook::<alloc[ffa4f392899a59d6]::boxed::Box<rustc_driver_impl[4eb5edc82c356bae]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x721839ee6213 - std::panicking::rust_panic_with_hook::hcd0adc674cd46b11
   8:     0x721839090011 - std[604c1f9fe749a3ed]::panicking::begin_panic::<rustc_errors[5a731b7919861d50]::ExplicitBug>::{closure#0}
   9:     0x7218390851f6 - std[604c1f9fe749a3ed]::sys::backtrace::__rust_end_short_backtrace::<std[604c1f9fe749a3ed]::panicking::begin_panic<rustc_errors[5a731b7919861d50]::ExplicitBug>::{closure#0}, !>
  10:     0x721839081c99 - std[604c1f9fe749a3ed]::panicking::begin_panic::<rustc_errors[5a731b7919861d50]::ExplicitBug>
  11:     0x721839099f71 - <rustc_errors[5a731b7919861d50]::diagnostic::BugAbort as rustc_errors[5a731b7919861d50]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x721839674093 - rustc_middle[3771967c7a7309a7]::util::bug::opt_span_bug_fmt::<rustc_span[af8ed1c1c0732708]::span_encoding::Span>::{closure#0}
  13:     0x72183965913a - rustc_middle[3771967c7a7309a7]::ty::context::tls::with_opt::<rustc_middle[3771967c7a7309a7]::util::bug::opt_span_bug_fmt<rustc_span[af8ed1c1c0732708]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:     0x721839658fcb - rustc_middle[3771967c7a7309a7]::ty::context::tls::with_context_opt::<rustc_middle[3771967c7a7309a7]::ty::context::tls::with_opt<rustc_middle[3771967c7a7309a7]::util::bug::opt_span_bug_fmt<rustc_span[af8ed1c1c0732708]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:     0x721837af4d70 - rustc_middle[3771967c7a7309a7]::util::bug::bug_fmt
  16:     0x72183abce06e - <rustc_middle[3771967c7a7309a7]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_type_ir[19e8b914371807c6]::fold::TypeFolder<rustc_middle[3771967c7a7309a7]::ty::context::TyCtxt>>::fold_ty
  17:     0x72183a8ab87f - <rustc_mir_dataflow[7733e32ee594b36e]::elaborate_drops::DropCtxt<rustc_mir_transform[fb5f6ede96b166b4]::elaborate_drops::ElaborateDropsCtxt>>::elaborate_drop
  18:     0x72183732106a - <rustc_mir_transform[fb5f6ede96b166b4]::elaborate_drops::ElaborateDrops as rustc_mir_transform[fb5f6ede96b166b4]::pass_manager::MirPass>::run_pass
  19:     0x72183a609a17 - rustc_mir_transform[fb5f6ede96b166b4]::run_analysis_to_runtime_passes
  20:     0x721837e03f7a - rustc_mir_transform[fb5f6ede96b166b4]::mir_drops_elaborated_and_const_checked
  21:     0x72183a9143f7 - rustc_query_impl[a4e03142de931e4f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a4e03142de931e4f]::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>>
  22:     0x72183a91474e - rustc_query_system[499354da019e31b1]::query::plumbing::try_execute_query::<rustc_query_impl[a4e03142de931e4f]::DynamicConfig<rustc_data_structures[5d10024945ee32aa]::vec_cache::VecCache<rustc_span[af8ed1c1c0732708]::def_id::LocalDefId, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[499354da019e31b1]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[a4e03142de931e4f]::plumbing::QueryCtxt, false>
  23:     0x72183a91418d - rustc_query_impl[a4e03142de931e4f]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  24:     0x72183a727239 - rustc_mir_transform[fb5f6ede96b166b4]::optimized_mir
  25:     0x72183a72695f - rustc_query_impl[a4e03142de931e4f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a4e03142de931e4f]::query_impl::optimized_mir::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>>
  26:     0x72183a6ef39f - rustc_query_system[499354da019e31b1]::query::plumbing::try_execute_query::<rustc_query_impl[a4e03142de931e4f]::DynamicConfig<rustc_query_system[499354da019e31b1]::query::caches::DefIdCache<rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[a4e03142de931e4f]::plumbing::QueryCtxt, false>
  27:     0x72183a6ee85f - rustc_query_impl[a4e03142de931e4f]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace
  28:     0x72183a995560 - rustc_middle[3771967c7a7309a7]::query::plumbing::query_get_at::<rustc_query_system[499354da019e31b1]::query::caches::DefIdCache<rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>>>
  29:     0x721839673925 - <rustc_middle[3771967c7a7309a7]::ty::context::TyCtxt>::coroutine_layout
  30:     0x721839e643fd - rustc_ty_utils[dd5813ad9bfce6f9]::layout::coroutine_layout
  31:     0x72183ac0a326 - rustc_ty_utils[dd5813ad9bfce6f9]::layout::layout_of_uncached
  32:     0x72183abfd7db - rustc_ty_utils[dd5813ad9bfce6f9]::layout::layout_of
  33:     0x72183abfd742 - rustc_query_impl[a4e03142de931e4f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a4e03142de931e4f]::query_impl::layout_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 16usize]>>
  34:     0x72183abfc785 - rustc_query_system[499354da019e31b1]::query::plumbing::try_execute_query::<rustc_query_impl[a4e03142de931e4f]::DynamicConfig<rustc_query_system[499354da019e31b1]::query::caches::DefaultCache<rustc_middle[3771967c7a7309a7]::ty::PseudoCanonicalInput<rustc_middle[3771967c7a7309a7]::ty::Ty>, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a4e03142de931e4f]::plumbing::QueryCtxt, false>
  35:     0x72183abfc3a2 - rustc_query_impl[a4e03142de931e4f]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace
  36:     0x72183b408a31 - <rustc_mir_transform[fb5f6ede96b166b4]::known_panics_lint::KnownPanicsLint as rustc_mir_transform[fb5f6ede96b166b4]::pass_manager::MirLint>::run_lint
  37:     0x72183a609a17 - rustc_mir_transform[fb5f6ede96b166b4]::run_analysis_to_runtime_passes
  38:     0x721837e03f7a - rustc_mir_transform[fb5f6ede96b166b4]::mir_drops_elaborated_and_const_checked
  39:     0x72183a9143f7 - rustc_query_impl[a4e03142de931e4f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a4e03142de931e4f]::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>>
  40:     0x72183a91474e - rustc_query_system[499354da019e31b1]::query::plumbing::try_execute_query::<rustc_query_impl[a4e03142de931e4f]::DynamicConfig<rustc_data_structures[5d10024945ee32aa]::vec_cache::VecCache<rustc_span[af8ed1c1c0732708]::def_id::LocalDefId, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[499354da019e31b1]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[a4e03142de931e4f]::plumbing::QueryCtxt, false>
  41:     0x72183a91418d - rustc_query_impl[a4e03142de931e4f]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  42:     0x72183aa57f71 - rustc_interface[6ccca059d52aaa56]::passes::run_required_analyses
  43:     0x72183b521bde - rustc_interface[6ccca059d52aaa56]::passes::analysis
  44:     0x72183b521baf - rustc_query_impl[a4e03142de931e4f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a4e03142de931e4f]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 0usize]>>
  45:     0x72183b5a2ad5 - rustc_query_system[499354da019e31b1]::query::plumbing::try_execute_query::<rustc_query_impl[a4e03142de931e4f]::DynamicConfig<rustc_query_system[499354da019e31b1]::query::caches::SingleCache<rustc_middle[3771967c7a7309a7]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[a4e03142de931e4f]::plumbing::QueryCtxt, false>
  46:     0x72183b5a280e - rustc_query_impl[a4e03142de931e4f]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  47:     0x72183b56601e - rustc_interface[6ccca059d52aaa56]::passes::create_and_enter_global_ctxt::<core[80152c8e99758bdd]::option::Option<rustc_interface[6ccca059d52aaa56]::queries::Linker>, rustc_driver_impl[4eb5edc82c356bae]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  48:     0x72183b5cb396 - rustc_interface[6ccca059d52aaa56]::interface::run_compiler::<(), rustc_driver_impl[4eb5edc82c356bae]::run_compiler::{closure#0}>::{closure#1}
  49:     0x72183b4456c7 - std[604c1f9fe749a3ed]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[6ccca059d52aaa56]::util::run_in_thread_with_globals<rustc_interface[6ccca059d52aaa56]::util::run_in_thread_pool_with_globals<rustc_interface[6ccca059d52aaa56]::interface::run_compiler<(), rustc_driver_impl[4eb5edc82c356bae]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  50:     0x72183b445b64 - <<std[604c1f9fe749a3ed]::thread::Builder>::spawn_unchecked_<rustc_interface[6ccca059d52aaa56]::util::run_in_thread_with_globals<rustc_interface[6ccca059d52aaa56]::util::run_in_thread_pool_with_globals<rustc_interface[6ccca059d52aaa56]::interface::run_compiler<(), rustc_driver_impl[4eb5edc82c356bae]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[80152c8e99758bdd]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  51:     0x72183b447141 - std::sys::pal::unix::thread::Thread::new::thread_start::h757ffa7c64c641a9
  52:     0x72183cbd0a94 - <unknown>
  53:     0x72183cc5da34 - clone
  54:                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 1.85.0-beta.4 (752fecf80 2025-01-17) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [mir_drops_elaborated_and_const_checked] elaborating drops for `foo::{closure#0}`
#1 [optimized_mir] optimizing MIR for `foo::{closure#0}`
end of query stack

• R: Future + Send: Correctly error on stable, ICE on beta
• R: Send: Correctly error on both stable and beta
• R: Future: ICE on both stable and beta
• R: /* nothing */: ICE on stable, correctly error on beta

(In other words: The code ICEs on stable iff there is not an R: Send bound. The code ICEs on beta iff there is an R: Future bound.)

[ranger-ross]

The most recent minimized example bisects to #134798 in nightly-2024-12-28

[theemathas]

cc @compiler-errors (author of the aforementioned PR)

[compiler-errors]

given this is error->ICE i'll consider this P-low. i'll look into a fix though.