ice: ProjectionKinds Deref and Field were mismatched

auto-reduced (treereduce-rust):

//

struct V<'a>((Option<&'a mut i32>,));

fn nested(v: &mut V<'_>) {
    (|| {
        V((_o,)) = v;
        v.0 = (None,);
    })();
}

original:

// Regression test for #89606. Used to ICE.
//
// check-pass
// revisions: twenty_eighteen twenty_twentyone
// [twenty_eighteen]compile-flags: --edition 2018
// [twenty_twentyone]compile-flags: --edition 2021

struct S<'a>(Option<&'a mut i32>);

fn by_ref(s: &mut S<'_>) {
    (|| {
        let S(_o) = s;
        s.0 = None;
    })();
}

fn by_value(s: S<'_>) {
    (|| {
        let S(ref _o) = s;
        let _g = s.0;
    })();
}

struct V<'a>((Option<&'a mut i32>,));

fn nested(v: &mut V<'_>) {
    (|| {
        struct S<'a>(Option<&'a mut i32>); V((_o,)) = v;
        v.0 = (None, );
    })();
}

fn main() {
    let mut s = S(None);
    by_ref(&mut s);
    by_value(s);

    let mut v = V((None, ));
    nested(&mut v);
}

Version information

rustc 1.76.0-nightly (e24e5af78 2023-11-21)
binary: rustc
commit-hash: e24e5af787f7015914cbf316063ed5821f370b71
commit-date: 2023-11-21
host: x86_64-unknown-linux-gnu
release: 1.76.0-nightly
LLVM version: 17.0.5

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

Program output

error[E0425]: cannot find value `_o` in this scope
 --> /tmp/icemaker_global_tempdir.4GO1XXNNDlqm/rustc_testrunner_tmpdir_reporting.Y3wqoQZ3yyr5/mvce.rs:7:12
  |
7 |         V((_o,)) = v;
  |            ^^ not found in this scope

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.4GO1XXNNDlqm/rustc_testrunner_tmpdir_reporting.Y3wqoQZ3yyr5/mvce.rs:10:2
   |
10 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.4GO1XXNNDlqm/rustc_testrunner_tmpdir_reporting.Y3wqoQZ3yyr5/mvce.rs`

error[E0308]: mismatched types
 --> /tmp/icemaker_global_tempdir.4GO1XXNNDlqm/rustc_testrunner_tmpdir_reporting.Y3wqoQZ3yyr5/mvce.rs:7:9
  |
7 |         V((_o,)) = v;
  |         ^^^^^^^^   - this expression has type `&mut V<'_>`
  |         |
  |         expected `&mut V<'_>`, found `V<'_>`

error: internal compiler error: compiler/rustc_hir_typeck/src/upvar.rs:704:30: ProjectionKinds Deref and Field were mismatched: (Deref, Field(0, 0))

thread 'rustc' panicked at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/compiler/rustc_errors/src/lib.rs:1660:9:
Box<dyn Any>
stack backtrace:
   0:     0x7efd84810afc - std::backtrace_rs::backtrace::libunwind::trace::h0b040baf97a1a814
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7efd84810afc - std::backtrace_rs::backtrace::trace_unsynchronized::h3bb4f35c883ef0b7
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7efd84810afc - std::sys_common::backtrace::_print_fmt::h7bc4c6c40e2dea38
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7efd84810afc - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::ha29c192b6f9a05c7
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7efd84863c80 - core::fmt::rt::Argument::fmt::hd5d7e2c681722c4a
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/core/src/fmt/rt.rs:142:9
   5:     0x7efd84863c80 - core::fmt::write::h44f28bd6729c28a7
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/core/src/fmt/mod.rs:1120:17
   6:     0x7efd8480491f - std::io::Write::write_fmt::h34e80b21f77f27fe
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/io/mod.rs:1762:15
   7:     0x7efd848108e4 - std::sys_common::backtrace::_print::hf6fce87ec4803f0c
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7efd848108e4 - std::sys_common::backtrace::print::h2c7cd590dc94a621
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7efd84813577 - std::panicking::default_hook::{{closure}}::ha2265235df34f52e
  10:     0x7efd848132df - std::panicking::default_hook::ha134722f286c6b3a
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/panicking.rs:292:9
  11:     0x7efd814f42b0 - std[9e66bc0d43e7428]::panicking::update_hook::<alloc[6053f7fa92048905]::boxed::Box<rustc_driver_impl[6d46853ed3c470a0]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7efd84813cb8 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h3506115e7630eb0e
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/alloc/src/boxed.rs:2021:9
  13:     0x7efd84813cb8 - std::panicking::rust_panic_with_hook::h7694bf37e5dc3efe
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/panicking.rs:783:13
  14:     0x7efd8193b174 - std[9e66bc0d43e7428]::panicking::begin_panic::<rustc_errors[561fbf43990526ac]::ExplicitBug>::{closure#0}
  15:     0x7efd819346d6 - std[9e66bc0d43e7428]::sys_common::backtrace::__rust_end_short_backtrace::<std[9e66bc0d43e7428]::panicking::begin_panic<rustc_errors[561fbf43990526ac]::ExplicitBug>::{closure#0}, !>
  16:     0x7efd8192edc6 - std[9e66bc0d43e7428]::panicking::begin_panic::<rustc_errors[561fbf43990526ac]::ExplicitBug>
  17:     0x7efd81914f14 - <rustc_errors[561fbf43990526ac]::HandlerInner>::bug::<alloc[6053f7fa92048905]::string::String>
  18:     0x7efd81914c1a - <rustc_errors[561fbf43990526ac]::Handler>::bug::<alloc[6053f7fa92048905]::string::String>
  19:     0x7efd819b692d - rustc_middle[999cff9f20269db6]::util::bug::opt_span_bug_fmt::<rustc_span[433598ff900853dd]::span_encoding::Span>::{closure#0}
  20:     0x7efd8199dc8a - rustc_middle[999cff9f20269db6]::ty::context::tls::with_opt::<rustc_middle[999cff9f20269db6]::util::bug::opt_span_bug_fmt<rustc_span[433598ff900853dd]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7efd8199db28 - rustc_middle[999cff9f20269db6]::ty::context::tls::with_context_opt::<rustc_middle[999cff9f20269db6]::ty::context::tls::with_opt<rustc_middle[999cff9f20269db6]::util::bug::opt_span_bug_fmt<rustc_span[433598ff900853dd]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7efd7f93fbf0 - rustc_middle[999cff9f20269db6]::util::bug::bug_fmt
  23:     0x7efd83e0551c - <[rustc_middle[999cff9f20269db6]::ty::closure::CapturedPlace]>::sort_by::<<rustc_hir_typeck[3784c5e6fa919bfa]::fn_ctxt::FnCtxt>::compute_min_captures::{closure#1}>::{closure#0}.cold.0
  24:     0x7efd8345f5eb - core[4409ec5cd92597ed]::slice::sort::insertion_sort_shift_left::<rustc_middle[999cff9f20269db6]::ty::closure::CapturedPlace, <[rustc_middle[999cff9f20269db6]::ty::closure::CapturedPlace]>::sort_by<<rustc_hir_typeck[3784c5e6fa919bfa]::fn_ctxt::FnCtxt>::compute_min_captures::{closure#1}>::{closure#0}>
  25:     0x7efd8345df5e - <rustc_hir_typeck[3784c5e6fa919bfa]::fn_ctxt::FnCtxt>::compute_min_captures
  26:     0x7efd831e8a25 - <rustc_hir_typeck[3784c5e6fa919bfa]::fn_ctxt::FnCtxt>::analyze_closure
  27:     0x7efd7f664942 - <rustc_hir_typeck[3784c5e6fa919bfa]::upvar::InferBorrowKindVisitor as rustc_hir[b19a94a0ae9cf398]::intravisit::Visitor>::visit_expr
  28:     0x7efd7f66474a - <rustc_hir_typeck[3784c5e6fa919bfa]::upvar::InferBorrowKindVisitor as rustc_hir[b19a94a0ae9cf398]::intravisit::Visitor>::visit_expr
  29:     0x7efd82a91d04 - <rustc_hir_typeck[3784c5e6fa919bfa]::upvar::InferBorrowKindVisitor as rustc_hir[b19a94a0ae9cf398]::intravisit::Visitor>::visit_block
  30:     0x7efd82af877e - rustc_hir_typeck[3784c5e6fa919bfa]::typeck
  31:     0x7efd82af7813 - rustc_query_impl[e3648600a664160f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e3648600a664160f]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[999cff9f20269db6]::query::erase::Erased<[u8; 8usize]>>
  32:     0x7efd82994cc3 - rustc_query_system[68ab24f02628e1a4]::query::plumbing::try_execute_query::<rustc_query_impl[e3648600a664160f]::DynamicConfig<rustc_query_system[68ab24f02628e1a4]::query::caches::VecCache<rustc_span[433598ff900853dd]::def_id::LocalDefId, rustc_middle[999cff9f20269db6]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[e3648600a664160f]::plumbing::QueryCtxt, false>
  33:     0x7efd82994950 - rustc_query_impl[e3648600a664160f]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  34:     0x7efd82bba240 - rustc_hir_analysis[ac2ddafd5ff93a2f]::check_crate
  35:     0x7efd82b4e4d7 - rustc_interface[79d196cce7f623b3]::passes::analysis
  36:     0x7efd82b4e11d - rustc_query_impl[e3648600a664160f]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e3648600a664160f]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[999cff9f20269db6]::query::erase::Erased<[u8; 1usize]>>
  37:     0x7efd8378aac0 - rustc_query_system[68ab24f02628e1a4]::query::plumbing::try_execute_query::<rustc_query_impl[e3648600a664160f]::DynamicConfig<rustc_query_system[68ab24f02628e1a4]::query::caches::SingleCache<rustc_middle[999cff9f20269db6]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[e3648600a664160f]::plumbing::QueryCtxt, false>
  38:     0x7efd8378a8c7 - rustc_query_impl[e3648600a664160f]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7efd83813678 - rustc_interface[79d196cce7f623b3]::interface::run_compiler::<core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>, rustc_driver_impl[6d46853ed3c470a0]::run_compiler::{closure#0}>::{closure#0}
  40:     0x7efd837a3054 - std[9e66bc0d43e7428]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[79d196cce7f623b3]::util::run_in_thread_with_globals<rustc_interface[79d196cce7f623b3]::util::run_in_thread_pool_with_globals<rustc_interface[79d196cce7f623b3]::interface::run_compiler<core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>, rustc_driver_impl[6d46853ed3c470a0]::run_compiler::{closure#0}>::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>
  41:     0x7efd837a2e7d - <<std[9e66bc0d43e7428]::thread::Builder>::spawn_unchecked_<rustc_interface[79d196cce7f623b3]::util::run_in_thread_with_globals<rustc_interface[79d196cce7f623b3]::util::run_in_thread_pool_with_globals<rustc_interface[79d196cce7f623b3]::interface::run_compiler<core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>, rustc_driver_impl[6d46853ed3c470a0]::run_compiler::{closure#0}>::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[4409ec5cd92597ed]::result::Result<(), rustc_span[433598ff900853dd]::ErrorGuaranteed>>::{closure#1} as core[4409ec5cd92597ed]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  42:     0x7efd8481db75 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he2fe898dabd7bf63
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/alloc/src/boxed.rs:2007:9
  43:     0x7efd8481db75 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h2e31e36ca472739b
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/alloc/src/boxed.rs:2007:9
  44:     0x7efd8481db75 - std::sys::unix::thread::Thread::new::thread_start::h72b7daa856b881db
                               at /rustc/e24e5af787f7015914cbf316063ed5821f370b71/library/std/src/sys/unix/thread.rs:108:17
  45:     0x7efd7e6aa9eb - <unknown>
  46:     0x7efd7e72e7cc - <unknown>
  47:                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 1.76.0-nightly (e24e5af78 2023-11-21) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `nested`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors

Some errors have detailed explanations: E0308, E0425, E0601.
For more information about an error, try `rustc --explain E0308`.

smaller

struct V(&mut i32);

fn nested(v: &V) {
    || {
        V(_somename) = v;
        v.0 = 0;
    };
}

Regression in nightly-2022-11-06

commit[0] 2022-11-04: Auto merge of #103978 - matthiaskrgr:rollup-iym9kmg, r=matthiaskrgr
commit[1] 2022-11-04: Auto merge of #103298 - ferrocene:pa-compile-flags-last, r=jyn514
commit[2] 2022-11-05: Auto merge of #103991 - matthiaskrgr:rollup-tj53nte, r=matthiaskrgr
commit[3] 2022-11-05: Auto merge of #103992 - weihanglo:update-cargo, r=weihanglo
commit[4] 2022-11-05: Auto merge of #103998 - Dylan-DPC:rollup-2nbmtc9, r=Dylan-DPC
commit[5] 2022-11-05: Auto merge of #103691 - michaelwoerister:consistent-slice-and-str-cpp-like-debuginfo-names, r=wesleywiser
commit[6] 2022-11-05: Auto merge of #103831 - chenyukang:yukang/fix-103751-ice, r=nagisa
commit[7] 2022-11-05: Auto merge of #104017 - matthiaskrgr:rollup-k8i0j9m, r=matthiaskrgr
commit[8] 2022-11-05: Auto merge of #102458 - JohnTitor:stabilize-instruction-set, r=oli-obk
ERROR: no CI builds available between 0950848 and 1286ee2 within last 167 days

@rustbot

@rustbot claim

Regression in nightly-2022-11-06

commit[0] 2022-11-04: Auto merge of #103978 - matthiaskrgr:rollup-iym9kmg, r=matthiaskrgr commit[1] 2022-11-04: Auto merge of #103298 - ferrocene:pa-compile-flags-last, r=jyn514 commit[2] 2022-11-05: Auto merge of #103991 - matthiaskrgr:rollup-tj53nte, r=matthiaskrgr commit[3] 2022-11-05: Auto merge of #103992 - weihanglo:update-cargo, r=weihanglo commit[4] 2022-11-05: Auto merge of #103998 - Dylan-DPC:rollup-2nbmtc9, r=Dylan-DPC commit[5] 2022-11-05: Auto merge of #103691 - michaelwoerister:consistent-slice-and-str-cpp-like-debuginfo-names, r=wesleywiser commit[6] 2022-11-05: Auto merge of #103831 - chenyukang:yukang/fix-103751-ice, r=nagisa commit[7] 2022-11-05: Auto merge of #104017 - matthiaskrgr:rollup-k8i0j9m, r=matthiaskrgr commit[8] 2022-11-05: Auto merge of #102458 - JohnTitor:stabilize-instruction-set, r=oli-obk ERROR: no CI builds available between 0950848 and 1286ee2 within last 167 days

The above bisection may be wrong. I got this instead:

Regression in nightly-2021-09-26

found 9 bors merge commits in the specified range
commit[0] 2021-09-24: Auto merge of #88872 - petrochenkov:getmod2, r=cjgillot
commit[1] 2021-09-24: Auto merge of #86246 - FabianWolff:issue-83471, r=estebank
commit[2] 2021-09-25: Auto merge of #89230 - workingjubilee:rollup-1swktdq, r=workingjubilee
commit[3] 2021-09-25: Auto merge of #87220 - petrochenkov:derivecfglimit2, r=Aaron1011
commit[4] 2021-09-25: Auto merge of #89237 - BoxyUwU:trackersMcCaller, r=eddyb
commit[5] 2021-09-25: Auto merge of #89030 - nbdd0121:box2, r=jonas-schievink
commit[6] 2021-09-25: Auto merge of #88243 - nikic:newpm-2, r=nagisa
commit[7] 2021-09-25: Auto merge of #87584 - adamgemmell:dev/asm-tests, r=Amanieu
commit[8] 2021-09-25: Auto merge of #88343 - steffahn:fix_code_spacing, r=jyn514
ERROR: no CI builds available between 7342213 and addb4da within last 167 days

The issue seems to be present since PR #89208 which is part of the rollup #89230

The ICE originates at the below code in the function rustc_hir_typeck::upvar::compute_min_captures():

rust/compiler/rustc_hir_typeck/src/upvar.rs

Lines 699 to 708 in 7ceaf19

    
           // We should have either a pair of `Deref`s or a pair of `Field`s. 
        
           // Anything else is a bug. 
        
           ( 
        
               l @ (ProjectionKind::Deref | ProjectionKind::Field(..)), 
        
               r @ (ProjectionKind::Deref | ProjectionKind::Field(..)), 
        
           ) => bug!( 
        
               "ProjectionKinds Deref and Field were mismatched: ({:?}, {:?})", 
        
               l, 
        
               r 
        
           ),

This code expects that all the captures of a given variable should have projection sequences that adhere to the following rules:

They contain only Deref, OpaqueCast or Field projection kinds (Index and Sublice are not allowed)
They all should have the exact same sequence e.g. Capture1: Deref.Field.Field and Capture2: Deref.Field.Field are okay but Capture1: Deref.Field.Deref and Capture2: Deref.Field.Field are not acceptable.

What causes the below snippet to ICE:

struct V(&mut i32);

fn nested(v: &V) {
    || {
        V(_somename) = v;
        v.0 = 0;
    };
}

is that compute_min_captures receives the following projection sequences for the arg v:

Capture1 : Field
Capture2 : Deref.Field

where Capture1 comes from the statement V(_somename) = v; and Capture2 comes from the statement v.0 = 0;

As these captures violate rule 2 above, an ICE ensues.

The code that is ICEing was introduced PR #89208 and has been ICEing ever since.

@wesleywiser

As for the fix, I feel there's little we can do to make these two captures:

Capture1 : Field
Capture2 : Deref.Field

align with each other as per rule 2. A statement like this V(_somename) = v;, which is destructuring v into an previously declared variable _someone, always results in a single Field projection whilev.0 = 0; always results in a Deref.Field projection sequence.

(Worth noting that if we change V(_somename) = v; to let V(_somename) = v;, i.e. we declare the variable while destructuring, then the ICE goes away. This is because let V(_somename) = v; results in a Deref.Field projection sequence which does not violate rule 2.)

A simple fix in my view would be to remove rule 2 and allow projection sequences like Field and Deref.Field to co-exist. We will just have figure out how to sort them w.r.t. each other. Wonder if just removing all Derefs from the projection sequences before comparing them could work. @wesleywiser might be able to shed some light.

Auto merge of rust-lang#118584 - gurry:118144-projection-kind-mismatc…

Navigation Menu

Repository navigation

ice: `ProjectionKinds Deref and Field were mismatched` #118144

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

	// We should have either a pair of `Deref`s or a pair of `Field`s.
	// Anything else is a bug.
	(
	l @ (ProjectionKind::Deref \| ProjectionKind::Field(..)),
	r @ (ProjectionKind::Deref \| ProjectionKind::Field(..)),
	) => bug!(
	"ProjectionKinds Deref and Field were mismatched: ({:?}, {:?})",
	l,
	r
	),

ice: ProjectionKinds Deref and Field were mismatched #118144

Description

Activity

matthiaskrgr commented on Nov 21, 2023

matthiaskrgr commented on Nov 21, 2023

gurry commented on Nov 27, 2023

gurry commented on Dec 3, 2023

gurry commented on Dec 3, 2023

gurry commented on Dec 3, 2023

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

ice: `ProjectionKinds Deref and Field were mismatched` #118144