ICE: `['?0, &ReEarlyBound(DefId ... is not fully resolved`

[matthiaskrgr]

File: /tmp/icemaker/68F3FC748CB07BD5DEB482970DD90B65A892A54B35FF38D622C323A548BD2156.rs

auto-reduced (treereduce-rust):

#![feature(min_specialization)]

trait MySpecTrait {
    fn f();
}

impl<'a, T: ?Sized> MySpecTrait for T {
    default fn f() {}
}

impl<'a, T: ?Sized> MySpecTrait for &'a T {
    fn f() {}
}

fn main() {}

original:

// Check that lifetime parameters are allowed in specializing impls.

// check-pass

#![feature(min_specialization)]

trait MySpecTrait {
    fn f();
}

impl<'a, T: ?Sized> MySpecTrait for T {
    default fn f() {}
}

impl<'a, T: ?Sized> MySpecTrait for &'a T {
    fn f() {}
}

fn main() {}

Version information

rustc 1.75.0-nightly (3fbcfd2b6 2023-10-19)
binary: rustc
commit-hash: 3fbcfd2b6f7030cb70328aa759107efc1516912c
commit-date: 2023-10-19
host: x86_64-unknown-linux-gnu
release: 1.75.0-nightly
LLVM version: 17.0.3

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

Program output

error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: `['?0, &ReEarlyBound(DefId(0:10 ~ 68F3FC748CB07BD5DEB482970DD90B65A892A54B35FF38D622C323A548BD2156[8290]::{impl#1}::'a), 0, 'a) T/#1]` is not fully resolved
  |
  = note: delayed at /rustc/3fbcfd2b6f7030cb70328aa759107efc1516912c/compiler/rustc_infer/src/infer/mod.rs:1434:26
             0: <rustc_errors::HandlerInner>::emit_diagnostic
             1: <rustc_session::session::Session>::delay_span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
             2: rustc_hir_analysis::impl_wf_check::min_specialization::check_always_applicable
             3: rustc_hir_analysis::impl_wf_check::check_mod_impl_wf
             4: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_mod_impl_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
             5: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalModDefId, rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
             6: rustc_query_impl::query_impl::check_mod_impl_wf::get_query_non_incr::__rust_end_short_backtrace
             7: rustc_hir_analysis::check_crate
             8: rustc_interface::passes::analysis
             9: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
            10: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
            11: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
            12: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
            13: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
            14: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                       at /rustc/3fbcfd2b6f7030cb70328aa759107efc1516912c/library/alloc/src/boxed.rs:2007:9
            15: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                       at /rustc/3fbcfd2b6f7030cb70328aa759107efc1516912c/library/alloc/src/boxed.rs:2007:9
            16: std::sys::unix::thread::Thread::new::thread_start
                       at /rustc/3fbcfd2b6f7030cb70328aa759107efc1516912c/library/std/src/sys/unix/thread.rs:108:17
            17: <unknown>
            18: <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 1.75.0-nightly (3fbcfd2b6 2023-10-19) running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack
error: aborting due to 2 previous errors

this one still crashes after #116663 cc @compiler-errors maybe :D

[compiler-errors]

I don't really see the point of opening a new issue for literally the same bug as #103708. I'd prefer if we just edit the issue in the description of that issue to side-step the error that caused the delay span bug not to trigger.

[compiler-errors]

Either that, or we should close #103708. There's no reason to close that one by adding a test -- the test isn't testing anything useful other than the fact that we don't ICE if we have already emitted an error.

[matthiaskrgr]

Ah I got that one from my big "files that crash rustc" folder after checking if there would be any examples left before seeing your comment in #103708 (fwiw for that crash we are down to 2 crashing files instead of maybe 100-150 before :) )
Feel free to close either of them 🤷

[compiler-errors]

Closing this one in favor of the older one -- I'll copy the autoreduced example into the PR description.