ICE: assertion failed: Binder == Binder

[matthiaskrgr]

auto-reduced (treereduce-rust):

const fn cmp(x: fn(), y: for<'a> fn()) -> bool {
    unsafe { x == y }
}

original:

const fn cmp(x: fn(), y: for<'a:> fn()) -> bool {
    unsafe { x == y }
    //~^ ERROR pointers cannot
}

fn main() {}

Version information

rustc 1.78.0-nightly (91cae1dcd 2024-02-27)
binary: rustc
commit-hash: 91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb
commit-date: 2024-02-27
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

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

Program output

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.lO8UkscWMZw4/rustc_testrunner_tmpdir_reporting.FY4MPNZohBHt/mvce.rs:3:2
  |
3 | }
  |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.lO8UkscWMZw4/rustc_testrunner_tmpdir_reporting.FY4MPNZohBHt/mvce.rs`

warning: unnecessary `unsafe` block
 --> /tmp/icemaker_global_tempdir.lO8UkscWMZw4/rustc_testrunner_tmpdir_reporting.FY4MPNZohBHt/mvce.rs:2:5
  |
2 |     unsafe { x == y }
  |     ^^^^^^ unnecessary `unsafe` block
  |
  = note: `#[warn(unused_unsafe)]` on by default

thread 'rustc' panicked at compiler/rustc_const_eval/src/transform/check_consts/check.rs:584:21:
assertion `left == right` failed
  left: Binder(fn(), [])
 right: Binder(fn(), [Region(BrNamed(DefId(0:4 ~ mvce[1b90]::cmp::'a), 'a))])
stack backtrace:
   0:     0x7f558238ca06 - std::backtrace_rs::backtrace::libunwind::trace::h6356805a047dd0f1
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f558238ca06 - std::backtrace_rs::backtrace::trace_unsynchronized::h57665ae10084ac28
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f558238ca06 - std::sys_common::backtrace::_print_fmt::h4c0b45ee6513471b
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f558238ca06 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::haf16cf243c101ffd
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f55823dd98c - core::fmt::rt::Argument::fmt::h223db55e42187d80
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/core/src/fmt/rt.rs:142:9
   5:     0x7f55823dd98c - core::fmt::write::h28c126feca2924d9
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f55823813cf - std::io::Write::write_fmt::h2ff3e839822231e6
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/io/mod.rs:1846:15
   7:     0x7f558238c7b4 - std::sys_common::backtrace::_print::hce6ed2eb89fc8621
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f558238c7b4 - std::sys_common::backtrace::print::hb8a6c09f8eb6f6ea
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f558238f4fb - std::panicking::default_hook::{{closure}}::h65070d5fef535888
  10:     0x7f558238f249 - std::panicking::default_hook::he2c4aec701a4c47a
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/panicking.rs:292:9
  11:     0x7f558529f37c - std[219737bc433d5307]::panicking::update_hook::<alloc[4f43f5786e9d4163]::boxed::Box<rustc_driver_impl[17f3281e62eb0b55]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f558238fc60 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h29905d5024db7b5d
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/alloc/src/boxed.rs:2030:9
  13:     0x7f558238fc60 - std::panicking::rust_panic_with_hook::hfbdb5f6b6c699264
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/panicking.rs:783:13
  14:     0x7f558238f9a2 - std::panicking::begin_panic_handler::{{closure}}::h7da42a48e307a26a
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/panicking.rs:657:13
  15:     0x7f558238cee6 - std::sys_common::backtrace::__rust_end_short_backtrace::h48881a1fe3ccdc5b
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7f558238f6d4 - rust_begin_unwind
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/panicking.rs:645:5
  17:     0x7f55823d9ea5 - core::panicking::panic_fmt::h75a5fa5cfa653b90
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/core/src/panicking.rs:72:14
  18:     0x7f55823da3eb - core::panicking::assert_failed_inner::h6048d140c707e98d
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/core/src/panicking.rs:342:17
  19:     0x7f5585217223 - core[ab6bada39f0d62f7]::panicking::assert_failed::<rustc_middle[e0d127506c37fb38]::ty::Ty, rustc_middle[e0d127506c37fb38]::ty::Ty>
  20:     0x7f5584599319 - <rustc_const_eval[d118eda0568e17d2]::transform::check_consts::check::Checker as rustc_middle[e0d127506c37fb38]::mir::visit::Visitor>::visit_basic_block_data
  21:     0x7f5586a08635 - <rustc_const_eval[d118eda0568e17d2]::transform::check_consts::check::Checker>::check_body
  22:     0x7f5586f3ee7c - rustc_mir_transform[f9758168ffa250ed]::mir_const_qualif
  23:     0x7f5586f3ec9b - rustc_query_impl[fae3b28032436758]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[fae3b28032436758]::query_impl::mir_const_qualif::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 4usize]>>
  24:     0x7f5586f3d744 - rustc_query_system[4cecc0fbb9d54d6e]::query::plumbing::try_execute_query::<rustc_query_impl[fae3b28032436758]::DynamicConfig<rustc_query_system[4cecc0fbb9d54d6e]::query::caches::DefIdCache<rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 4usize]>>, false, false, false>, rustc_query_impl[fae3b28032436758]::plumbing::QueryCtxt, false>
  25:     0x7f5586f3d149 - rustc_query_impl[fae3b28032436758]::query_impl::mir_const_qualif::get_query_non_incr::__rust_end_short_backtrace
  26:     0x7f5586f3c8e3 - rustc_middle[e0d127506c37fb38]::query::plumbing::query_get_at::<rustc_query_system[4cecc0fbb9d54d6e]::query::caches::DefIdCache<rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 4usize]>>>
  27:     0x7f558478cd16 - rustc_mir_transform[f9758168ffa250ed]::mir_promoted
  28:     0x7f5586b60492 - rustc_query_impl[fae3b28032436758]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[fae3b28032436758]::query_impl::mir_promoted::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 16usize]>>
  29:     0x7f5586b60750 - rustc_query_system[4cecc0fbb9d54d6e]::query::plumbing::try_execute_query::<rustc_query_impl[fae3b28032436758]::DynamicConfig<rustc_query_system[4cecc0fbb9d54d6e]::query::caches::VecCache<rustc_span[f729f3d7b7758c04]::def_id::LocalDefId, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[fae3b28032436758]::plumbing::QueryCtxt, false>
  30:     0x7f558740530f - rustc_query_impl[fae3b28032436758]::query_impl::mir_promoted::get_query_non_incr::__rust_end_short_backtrace
  31:     0x7f558740540c - rustc_borrowck[d04c300f4bae4997]::mir_borrowck
  32:     0x7f5587405357 - rustc_query_impl[fae3b28032436758]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[fae3b28032436758]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 8usize]>>
  33:     0x7f55867701b0 - rustc_query_system[4cecc0fbb9d54d6e]::query::plumbing::try_execute_query::<rustc_query_impl[fae3b28032436758]::DynamicConfig<rustc_query_system[4cecc0fbb9d54d6e]::query::caches::VecCache<rustc_span[f729f3d7b7758c04]::def_id::LocalDefId, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[fae3b28032436758]::plumbing::QueryCtxt, false>
  34:     0x7f558676fd8c - rustc_query_impl[fae3b28032436758]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  35:     0x7f55871c590c - rustc_interface[db8a4e7a90e6d56e]::passes::analysis
  36:     0x7f55871c5419 - rustc_query_impl[fae3b28032436758]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[fae3b28032436758]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 1usize]>>
  37:     0x7f55873345e5 - rustc_query_system[4cecc0fbb9d54d6e]::query::plumbing::try_execute_query::<rustc_query_impl[fae3b28032436758]::DynamicConfig<rustc_query_system[4cecc0fbb9d54d6e]::query::caches::SingleCache<rustc_middle[e0d127506c37fb38]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[fae3b28032436758]::plumbing::QueryCtxt, false>
  38:     0x7f5587334349 - rustc_query_impl[fae3b28032436758]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7f558733bed6 - rustc_interface[db8a4e7a90e6d56e]::interface::run_compiler::<core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>, rustc_driver_impl[17f3281e62eb0b55]::run_compiler::{closure#0}>::{closure#0}
  40:     0x7f55875e0a85 - std[219737bc433d5307]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[db8a4e7a90e6d56e]::util::run_in_thread_with_globals<rustc_interface[db8a4e7a90e6d56e]::util::run_in_thread_pool_with_globals<rustc_interface[db8a4e7a90e6d56e]::interface::run_compiler<core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>, rustc_driver_impl[17f3281e62eb0b55]::run_compiler::{closure#0}>::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>
  41:     0x7f55875e08b2 - <<std[219737bc433d5307]::thread::Builder>::spawn_unchecked_<rustc_interface[db8a4e7a90e6d56e]::util::run_in_thread_with_globals<rustc_interface[db8a4e7a90e6d56e]::util::run_in_thread_pool_with_globals<rustc_interface[db8a4e7a90e6d56e]::interface::run_compiler<core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>, rustc_driver_impl[17f3281e62eb0b55]::run_compiler::{closure#0}>::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[ab6bada39f0d62f7]::result::Result<(), rustc_span[f729f3d7b7758c04]::ErrorGuaranteed>>::{closure#1} as core[ab6bada39f0d62f7]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  42:     0x7f5582399635 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h5d5208573d833f07
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/alloc/src/boxed.rs:2016:9
  43:     0x7f5582399635 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hc13d38a59b83ddfd
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/alloc/src/boxed.rs:2016:9
  44:     0x7f5582399635 - std::sys::pal::unix::thread::Thread::new::thread_start::he9a07be3a69d4045
                               at /rustc/91cae1dcdcf1a31bd8a92e4a63793d65cfe289bb/library/std/src/sys/pal/unix/thread.rs:108:17
  45:     0x7f558218155a - <unknown>
  46:     0x7f55821fea3c - <unknown>
  47:                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: rustc 1.78.0-nightly (91cae1dcd 2024-02-27) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_const_qualif] const checking `cmp`
#1 [mir_promoted] promoting constants in MIR for `cmp`
#2 [mir_borrowck] borrow-checking `cmp`
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 1 previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0601`.

[matthiaskrgr]

Regression in #118937 cc @lcnr

[lcnr]

that seems off 😅 this PR should not result in behavior differences

[matthiaskrgr]

ah yes my bad :D
I left in -Znext-solver=coherenceby accident from a previous bisection and that was the pr that added the flag 😆

[lcnr]

rust/compiler/rustc_const_eval/src/transform/check_consts/check.rs

Lines 583 to 597 in b6e4299

	} else if lhs_ty.is_fn_ptr() || lhs_ty.is_unsafe_ptr() {
	assert_eq!(lhs_ty, rhs_ty);
	assert!(matches!(
	op,
	BinOp::Eq
	| BinOp::Ne
	| BinOp::Le
	| BinOp::Lt
	| BinOp::Ge
	| BinOp::Gt
	| BinOp::Offset
	));
	self.check_op(ops::RawPtrComparison);
	} else if lhs_ty.is_floating_point() || rhs_ty.is_floating_point() {

should exist since pretty much forever 😁 1.48

[matthiaskrgr]

Regression in nightly-2023-04-20

fetching (via remote github) commits from max(c609da5, 2023-04-17) to 39c6804
ending github query because we found starting sha: c609da5
get_commits_between returning commits, len: 10
commit[0] 2023-04-18: Auto merge of #109772 - petrochenkov:slimchild, r=cjgillot
commit[1] 2023-04-18: Auto merge of #110083 - saethlin:encode-hashes-as-bytes, r=cjgillot
commit[2] 2023-04-19: Auto merge of #110229 - jyn514:download-rustc-tests, r=albertlarsan68
commit[3] 2023-04-19: Auto merge of #110477 - miguelraz:canoodling2-electric-boogaloo, r=compiler-errors
commit[4] 2023-04-19: Auto merge of #110522 - matthiaskrgr:rollup-9m7rw3u, r=matthiaskrgr
commit[5] 2023-04-19: Auto merge of #110407 - Nilstrieb:fluent-macro, r=davidtwco
commit[6] 2023-04-19: Auto merge of #110393 - fee1-dead-contrib:rm-const-traits, r=oli-obk
commit[7] 2023-04-19: Auto merge of #110496 - WaffleLapkin:🏳️‍⚧️sound, r=compiler-errors
commit[8] 2023-04-19: Auto merge of #110546 - matthiaskrgr:rollup-346kik6, r=matthiaskrgr
commit[9] 2023-04-19: Auto merge of #106704 - ecnelises:big_archive, r=bjorn3

[matthiaskrgr]

This might be related to #110393 cc @fee1-dead

one nightly before this errors with

error[E0277]: can't compare `fn()` with `_` in const contexts
 --> a.rs:2:16
  |
2 |     unsafe { x == y }
  |                ^^ no implementation for `fn() == _`
  |
  = help: the trait `~const PartialEq<_>` is not implemented for `fn()`
note: the trait `PartialEq<_>` is implemented for `fn()`, but that implementation is not `const`
 --> a.rs:2:16
  |
2 |     unsafe { x == y }
  |                ^^

so maybe const-related

[lcnr]

the cause is that the assert mentioned in #121688 (comment) is wrong. COmparing pointers with different bound vars is ok. This should either use actual semantic equality or just yeet the assert