search

rust-lang / rust

Empowering everyone to build reliable and efficient software.
https://www.rust-lang.org
Other
98.31k stars 12.72k forks source link

ICE: solver coherence: 'called `Result::unwrap()` on an `Err` value: Sorts(ExpectedFound { expected: u32, found: u16 })' #124422

Closed matthiaskrgr closed 6 months ago

matthiaskrgr commented 6 months ago

auto-reduced (treereduce-rust):


#![feature(specialization)] //~ WARN the feature `specialization` is incomplete

trait Assoc {
    type Output;
}

impl<T> Assoc for T {
    default 
}

impl Assoc for u16 { type Output = u16; }

trait Foo {}
impl Foo for u32 {}

impl Foo for <u16 as Assoc>::Output {}

original:

//@ check-pass

// Test that impls on projected self types can resolve overlap, even when the
// projections involve specialization, so long as the associated type is
// provided by the most specialized impl.

#![feature(specialization)] //~ WARN the feature `specialization` is incomplete

trait Assoc {
    type Output;
}

impl<T> Assoc for T {
    default type Output = bool;
}

impl Assoc for u8 { type Output = u8; }
impl Assoc for u16 { type Output = u16; }

trait Foo {}
impl Foo for u32 {}
impl Foo for <u8 as Assoc>::Output {}
impl Foo for <u16 as Assoc>::Output {}

fn main() {}

Version information

rustc 1.79.0-nightly (1b3a32958 2024-04-26)
binary: rustc
commit-hash: 1b3a32958bb54bde45e693217e8f7469459e5865
commit-date: 2024-04-26
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.4

Command: /home/matthias/.rustup/toolchains/master/bin/rustc -Znext-solver=coherence

Program output

``` error: expected one of `!` or `::`, found `}` --> /tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs:15:1 | 13 | impl Assoc for T { | - while parsing this item list starting here 14 | default | - expected one of `!` or `::` 15 | } | ^ | | | unexpected token | the item list ends here warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes --> /tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs:7:12 | 7 | #![feature(specialization)] //~ WARN the feature `specialization` is incomplete | ^^^^^^^^^^^^^^ | = note: see issue #31844 for more information = help: consider using `min_specialization` instead, which is more stable and complete = note: `#[warn(incomplete_features)]` on by default error[E0601]: `main` function not found in crate `mvce` --> /tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs:23:39 | 23 | impl Foo for ::Output {} | ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs` error[E0046]: not all trait items implemented, missing: `Output` --> /tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs:13:1 | 10 | type Output; | ----------- `Output` from trait ... 13 | impl Assoc for T { | ^^^^^^^^^^^^^^^^^^^ missing `Output` in implementation error[E0520]: `Output` specializes an item from a parent `impl`, but that item is not marked `default` --> /tmp/icemaker_global_tempdir.VcNpYtiehp9n/rustc_testrunner_tmpdir_reporting.DaVMlM63CQKW/mvce.rs:18:22 | 13 | impl Assoc for T { | ------------------- parent `impl` is here ... 18 | impl Assoc for u16 { type Output = u16; } | ^^^^^^^^^^^ cannot specialize default item `Output` | = note: to specialize, `Output` in the parent `impl` must be marked `default` thread 'rustc' panicked at compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs:352:18: called `Result::unwrap()` on an `Err` value: Sorts(ExpectedFound { expected: u32, found: u16 }) stack backtrace: 0: 0x76f272ab6015 - std::backtrace_rs::backtrace::libunwind::trace::h4c55e2c372987d5e at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5 1: 0x76f272ab6015 - std::backtrace_rs::backtrace::trace_unsynchronized::hce938b03028abd04 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x76f272ab6015 - std::sys_common::backtrace::_print_fmt::h7224c4dd9bb24216 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys_common/backtrace.rs:68:5 3: 0x76f272ab6015 - ::fmt::h90199bc1e9538393 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys_common/backtrace.rs:44:22 4: 0x76f272b0527b - core::fmt::rt::Argument::fmt::h99091d315a9edc70 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/core/src/fmt/rt.rs:165:63 5: 0x76f272b0527b - core::fmt::write::h957cfb08804d4951 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/core/src/fmt/mod.rs:1157:21 6: 0x76f272aaac3f - std::io::Write::write_fmt::h403b2ebe17559453 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/io/mod.rs:1832:15 7: 0x76f272ab5dee - std::sys_common::backtrace::_print::h32e8cdac40e53a67 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys_common/backtrace.rs:47:5 8: 0x76f272ab5dee - std::sys_common::backtrace::print::h0fe3ded68e4b3f7a at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys_common/backtrace.rs:34:9 9: 0x76f272ab8759 - std::panicking::default_hook::{{closure}}::hb64b24bf17e43a2c 10: 0x76f272ab849d - std::panicking::default_hook::hf8b5abecad7ca8bf at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/panicking.rs:298:9 11: 0x76f26f4326bc - std[cda2fed61da7e3aa]::panicking::update_hook::>::{closure#0} 12: 0x76f272ab8e56 - as core::ops::function::Fn>::call::h22c7123f3e8870f3 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/alloc/src/boxed.rs:2036:9 13: 0x76f272ab8e56 - std::panicking::rust_panic_with_hook::ha6622cef7edeb437 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/panicking.rs:799:13 14: 0x76f272ab8c04 - std::panicking::begin_panic_handler::{{closure}}::h4a88a108ee42ac5f at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/panicking.rs:664:13 15: 0x76f272ab64d9 - std::sys_common::backtrace::__rust_end_short_backtrace::h99b2927289cdd120 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys_common/backtrace.rs:171:18 16: 0x76f272ab8937 - rust_begin_unwind at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/panicking.rs:652:5 17: 0x76f272b01743 - core::panicking::panic_fmt::h6753019afa32865b at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/core/src/panicking.rs:72:14 18: 0x76f272b01d86 - core::result::unwrap_failed::h355d7b82293d1305 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/core/src/result.rs:1654:5 19: 0x76f270d93278 - ::unify_query_var_values 20: 0x76f26ff70235 - ::visit_goal 21: 0x76f26ff707e3 - ::visit_goal 22: 0x76f270d943c4 - rustc_trait_selection[4ae1fc89cbf26186]::traits::coherence::overlap 23: 0x76f2714d7d40 - ::insert 24: 0x76f26e0d1218 - ::insert 25: 0x76f27088f4fc - rustc_trait_selection[4ae1fc89cbf26186]::traits::specialize::specialization_graph_provider 26: 0x76f27088f05f - rustc_query_impl[9f33ac55070ec74]::plumbing::__rust_begin_short_backtrace::> 27: 0x76f270891a4e - rustc_query_system[f4e6670f65fd34a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[9f33ac55070ec74]::plumbing::QueryCtxt, false> 28: 0x76f270f64c74 - rustc_query_impl[9f33ac55070ec74]::query_impl::specialization_graph_of::get_query_non_incr::__rust_end_short_backtrace 29: 0x76f270d2b170 - rustc_hir_analysis[63d5f7453e3e6b9f]::coherence::coherent_trait 30: 0x76f270d2ae65 - rustc_query_impl[9f33ac55070ec74]::plumbing::__rust_begin_short_backtrace::> 31: 0x76f270b5bfd8 - rustc_query_system[f4e6670f65fd34a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[9f33ac55070ec74]::plumbing::QueryCtxt, false> 32: 0x76f270b5ac09 - rustc_query_impl[9f33ac55070ec74]::query_impl::coherent_trait::get_query_non_incr::__rust_end_short_backtrace 33: 0x76f270eb4ea8 - rustc_hir_analysis[63d5f7453e3e6b9f]::check::wfcheck::check_well_formed 34: 0x76f270eb2c6d - rustc_query_impl[9f33ac55070ec74]::plumbing::__rust_begin_short_backtrace::> 35: 0x76f270eb2400 - rustc_query_system[f4e6670f65fd34a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[9f33ac55070ec74]::plumbing::QueryCtxt, false> 36: 0x76f270eb217f - rustc_query_impl[9f33ac55070ec74]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace 37: 0x76f270eb00f7 - rustc_hir_analysis[63d5f7453e3e6b9f]::check::wfcheck::check_mod_type_wf 38: 0x76f270eaff27 - rustc_query_impl[9f33ac55070ec74]::plumbing::__rust_begin_short_backtrace::> 39: 0x76f2715da0c6 - rustc_query_system[f4e6670f65fd34a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[9f33ac55070ec74]::plumbing::QueryCtxt, false> 40: 0x76f2715d9e7f - rustc_query_impl[9f33ac55070ec74]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace 41: 0x76f270b48e1b - rustc_hir_analysis[63d5f7453e3e6b9f]::check_crate 42: 0x76f270b2ae87 - rustc_interface[2c0a8ee4ca531b31]::passes::analysis 43: 0x76f270b2a9db - rustc_query_impl[9f33ac55070ec74]::plumbing::__rust_begin_short_backtrace::> 44: 0x76f2715f35e5 - rustc_query_system[f4e6670f65fd34a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[9f33ac55070ec74]::plumbing::QueryCtxt, false> 45: 0x76f2715f3349 - rustc_query_impl[9f33ac55070ec74]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 46: 0x76f27145210e - rustc_interface[2c0a8ee4ca531b31]::interface::run_compiler::, rustc_driver_impl[37b3e731affd2934]::run_compiler::{closure#0}>::{closure#1} 47: 0x76f27143eb09 - std[cda2fed61da7e3aa]::sys_common::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[37b3e731affd2934]::run_compiler::{closure#0}>::{closure#1}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>>::{closure#0}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>> 48: 0x76f27143e8ba - <::spawn_unchecked_, rustc_driver_impl[37b3e731affd2934]::run_compiler::{closure#0}>::{closure#1}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>>::{closure#0}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[1844992cd7eaeb93]::result::Result<(), rustc_span[a27099297aeb4f84]::ErrorGuaranteed>>::{closure#2} as core[1844992cd7eaeb93]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 49: 0x76f272ac2c8b - as core::ops::function::FnOnce>::call_once::hfbef881afe54fc64 at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/alloc/src/boxed.rs:2022:9 50: 0x76f272ac2c8b - as core::ops::function::FnOnce>::call_once::h248e9437ec3cc6be at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/alloc/src/boxed.rs:2022:9 51: 0x76f272ac2c8b - std::sys::pal::unix::thread::Thread::new::thread_start::h8f5142e9cff5a60d at /rustc/1b3a32958bb54bde45e693217e8f7469459e5865/library/std/src/sys/pal/unix/thread.rs:108:17 52: 0x76f26c2a955a - 53: 0x76f26c326a3c - 54: 0x0 - 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 1.79.0-nightly (1b3a32958 2024-04-26) running on x86_64-unknown-linux-gnu note: compiler flags: -Z next-solver=coherence -Z dump-mir-dir=dir query stack during panic: #0 [specialization_graph_of] building specialization graph of trait `Foo` #1 [coherent_trait] coherence checking all impls of trait `Foo` #2 [check_well_formed] checking that `` is well-formed #3 [check_mod_type_wf] checking that types are well-formed in top-level module #4 [analysis] running analysis passes on this crate end of query stack error: aborting due to 4 previous errors; 1 warning emitted Some errors have detailed explanations: E0046, E0520, E0601. For more information about an error, try `rustc --explain E0046`. ```

@rustbot label +F-specialization

matthiaskrgr commented 6 months ago

122385 fyi @lcnr

matthiaskrgr commented 6 months ago

There is also a ProofTreeVisitor issue causing an ICE when compiling alloc which I will handle in a separate PR.

this is probably the same problem here. When compiling ./library/alloc/src/lib.rs" with 2021, we run into Sorts(ExpectedFound { expected: string::String, found: str }) but I have not bothered trying to reduce that :sweat_smile:

lqd commented 6 months ago

The original code already produces that ICE (so I guess that via specialization-overlap-projection.rs this is already a known issue?), and is a check-pass test. In these situations, your reduction procedure could just check that the flag is the cause of the error first, and then minimize the code.

That is, instead of reducing with a condition like rustc code.rs -Znext-solver=coherence &| grep ICE, using a condition like rustc code.rs && rustc code -Znext-solver=coherence &| grep ICE.

This would keep the *-pass property, and fuzz deeper within rustc by not being limited by unrelated basic syntax errors in general. I mean, unless you're fuzzing diagnostics or failure paths in particular for *-fail tests, which is useful in its own right. Otherwise, the procedure still has a bias towards that, but it's not intentional, and coverage is reduced.

#![feature(specialization)]

trait Assoc {
    type Output;
}

impl<T> Assoc for T {
    default type Output = bool;
}

impl Assoc for u16 { type Output = u16; }

trait Foo {}
impl Foo for u32 {}
impl Foo for <u16 as Assoc>::Output {}

fn main() {}
matthiaskrgr commented 6 months ago

There is no fuzzing involved here. The ICE was detected on the original straight form the rustc repo and the responsible compiler flag was found (all unrelated compiler flags are dismissed). Then with the reduced set of flags, I run https://github.com/langston-barrett/treereduce to automatically reduce the file, as long as the ice still triggers with the reduced set of flags and this becomes reduced snippet from which I generate the markdown report.

lqd commented 6 months ago

Right I'm saying this can be suboptimal as it introduces new unrelated errors. It turned something that worked without the flag and ICEd with it, into something that fails without the flag and still ICEs with the flag. This can be prevented during reduction.

The reduced snippet would have to be fixed to remove the unrelated errors when fixing the ICE, or worse it could be ignored in favor of the original unreduced piece of code.