ICE: entered unreachable code: we captured two identical projections

[matthiaskrgr]

Code

enum Either {
    One(X),
    Two(X),
}

struct X(Y);

struct Y;

fn move_into_fnmut() {
    let x = move_into_fnmut();

    consume_fnmut(|| {
        X(_t) = x;

        Either::Two(_t) = x;
    });
}

Meta

rustc --version --verbose:

rustc 1.70.0-nightly (171693274 2023-03-14)
binary: rustc
commit-hash: 1716932743a7b3705cbf0c34db0c4e070ed1930d
commit-date: 2023-03-14
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7

Error output

<output>

Backtrace

thread 'rustc' panicked at 'internal error: entered unreachable code: we captured two identical projections: capture1 = CapturedPlace { var_ident: x#0, place: Place { base_ty: (), base: Upvar(UpvarId(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).6);`x`;DefId(0:16 ~ treereduce[357c]::move_into_fnmut::{closure#0}))), projections: [Projection { ty: X, kind: Field(0, 1) }] }, info: CaptureInfo { capture_kind_expr_id: Some(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).39)), path_expr_id: Some(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).39)), capture_kind: ByValue }, mutability: Not, region: None }, capture2 = CapturedPlace { var_ident: x#0, place: Place { base_ty: (), base: Upvar(UpvarId(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).6);`x`;DefId(0:16 ~ treereduce[357c]::move_into_fnmut::{closure#0}))), projections: [Projection { ty: Y, kind: Field(0, 0) }] }, info: CaptureInfo { capture_kind_expr_id: Some(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).22)), path_expr_id: Some(HirId(DefId(0:15 ~ treereduce[357c]::move_into_fnmut).22)), capture_kind: ByValue }, mutability: Not, region: None }', compiler/rustc_hir_typeck/src/upvar.rs:715:17
stack backtrace:
   0:     0x7f142776651a - std::backtrace_rs::backtrace::libunwind::trace::hb525d69e070ade81
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f142776651a - std::backtrace_rs::backtrace::trace_unsynchronized::hc013ba6c022c8cc0
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f142776651a - std::sys_common::backtrace::_print_fmt::hc99069d428720acc
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f142776651a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h6b2dfd5fb54878e3
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f14277c9c5e - core::fmt::write::he277a08b33a83db8
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/core/src/fmt/mod.rs:1232:17
   5:     0x7f1427759375 - std::io::Write::write_fmt::h6a5aa3320aae0280
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/io/mod.rs:1684:15
   6:     0x7f14277662e5 - std::sys_common::backtrace::_print::h763b5adb4e9083ff
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7f14277662e5 - std::sys_common::backtrace::print::h5a4028b32a3df8a2
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7f142776905f - std::panicking::default_hook::{{closure}}::h0c8c81b9641f8819
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/panicking.rs:271:22
   9:     0x7f1427768d9b - std::panicking::default_hook::h5bf7cd33f355743b
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/panicking.rs:290:9
  10:     0x7f142aa577f5 - rustc_driver_impl[aa1a5107c9e4d916]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7f142776989d - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h31d3f61cac634989
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/alloc/src/boxed.rs:2002:9
  12:     0x7f142776989d - std::panicking::rust_panic_with_hook::h11aed2986f5c5154
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/panicking.rs:696:13
  13:     0x7f1427769619 - std::panicking::begin_panic_handler::{{closure}}::h5030a267c334a760
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/panicking.rs:583:13
  14:     0x7f1427766986 - std::sys_common::backtrace::__rust_end_short_backtrace::hf19b9029d2a05570
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys_common/backtrace.rs:150:18
  15:     0x7f1427769322 - rust_begin_unwind
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/panicking.rs:579:5
  16:     0x7f14277c5fb3 - core::panicking::panic_fmt::hc179041817e007c3
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/core/src/panicking.rs:64:14
  17:     0x7f1429f04c9a - <[rustc_middle[91c99f5af0859808]::ty::closure::CapturedPlace]>::sort_by::<<rustc_hir_typeck[abe2c3cd9c1436d1]::fn_ctxt::FnCtxt>::compute_min_captures::{closure#1}>::{closure#0}
  18:     0x7f1429f04a7f - core[93f4c45d685c579b]::slice::sort::insertion_sort_shift_left::<rustc_middle[91c99f5af0859808]::ty::closure::CapturedPlace, <[rustc_middle[91c99f5af0859808]::ty::closure::CapturedPlace]>::sort_by<<rustc_hir_typeck[abe2c3cd9c1436d1]::fn_ctxt::FnCtxt>::compute_min_captures::{closure#1}>::{closure#0}>
  19:     0x7f1429f01f95 - <rustc_hir_typeck[abe2c3cd9c1436d1]::fn_ctxt::FnCtxt>::compute_min_captures
  20:     0x7f1429efb5fe - <rustc_hir_typeck[abe2c3cd9c1436d1]::fn_ctxt::FnCtxt>::analyze_closure
  21:     0x7f1428ac5e79 - <rustc_hir_typeck[abe2c3cd9c1436d1]::upvar::InferBorrowKindVisitor as rustc_hir[2286395576989f03]::intravisit::Visitor>::visit_expr
  22:     0x7f1428ac6067 - <rustc_hir_typeck[abe2c3cd9c1436d1]::upvar::InferBorrowKindVisitor as rustc_hir[2286395576989f03]::intravisit::Visitor>::visit_expr
  23:     0x7f1428ac60a8 - <rustc_hir_typeck[abe2c3cd9c1436d1]::upvar::InferBorrowKindVisitor as rustc_hir[2286395576989f03]::intravisit::Visitor>::visit_expr
  24:     0x7f142999b7d5 - rustc_hir_typeck[abe2c3cd9c1436d1]::typeck
  25:     0x7f142951c7a6 - rustc_query_system[d086d80e7946fec]::query::plumbing::try_execute_query::<rustc_query_impl[4365cf0f327aa4bf]::queries::typeck, rustc_query_impl[4365cf0f327aa4bf]::plumbing::QueryCtxt>
  26:     0x7f142a1f4402 - rustc_data_structures[fc6c1c49e6433a48]::sync::par_for_each_in::<&[rustc_span[3a8ff7714ec0cd56]::def_id::LocalDefId], <rustc_middle[91c99f5af0859808]::hir::map::Map>::par_body_owners<rustc_hir_typeck[abe2c3cd9c1436d1]::typeck_item_bodies::{closure#0}>::{closure#0}>
  27:     0x7f142a1f41bf - rustc_hir_typeck[abe2c3cd9c1436d1]::typeck_item_bodies
  28:     0x7f142a26ff97 - rustc_query_system[d086d80e7946fec]::query::plumbing::try_execute_query::<rustc_query_impl[4365cf0f327aa4bf]::queries::typeck_item_bodies, rustc_query_impl[4365cf0f327aa4bf]::plumbing::QueryCtxt>
  29:     0x7f142a26fc6c - <rustc_query_impl[4365cf0f327aa4bf]::Queries as rustc_middle[91c99f5af0859808]::ty::query::QueryEngine>::typeck_item_bodies
  30:     0x7f1428e1fb96 - <rustc_session[66f881e4886b517]::session::Session>::time::<(), rustc_hir_analysis[2cd7f2356faca1ef]::check_crate::{closure#7}>
  31:     0x7f1428e1c878 - rustc_hir_analysis[2cd7f2356faca1ef]::check_crate
  32:     0x7f1428e145e2 - rustc_interface[92ae9247c658ed28]::passes::analysis
  33:     0x7f142a27b95c - rustc_query_system[d086d80e7946fec]::query::plumbing::try_execute_query::<rustc_query_impl[4365cf0f327aa4bf]::queries::analysis, rustc_query_impl[4365cf0f327aa4bf]::plumbing::QueryCtxt>
  34:     0x7f142a27b650 - <rustc_query_impl[4365cf0f327aa4bf]::Queries as rustc_middle[91c99f5af0859808]::ty::query::QueryEngine>::analysis
  35:     0x7f142a0a3369 - <rustc_middle[91c99f5af0859808]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[aa1a5107c9e4d916]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>>
  36:     0x7f1429c7cfa8 - rustc_span[3a8ff7714ec0cd56]::with_source_map::<core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>, rustc_interface[92ae9247c658ed28]::interface::run_compiler<core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>, rustc_driver_impl[aa1a5107c9e4d916]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  37:     0x7f1429c7420c - std[8d53a76fa3b550eb]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[92ae9247c658ed28]::util::run_in_thread_pool_with_globals<rustc_interface[92ae9247c658ed28]::interface::run_compiler<core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>, rustc_driver_impl[aa1a5107c9e4d916]::run_compiler::{closure#1}>::{closure#0}, core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>>
  38:     0x7f1429c73c3a - <<std[8d53a76fa3b550eb]::thread::Builder>::spawn_unchecked_<rustc_interface[92ae9247c658ed28]::util::run_in_thread_pool_with_globals<rustc_interface[92ae9247c658ed28]::interface::run_compiler<core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>, rustc_driver_impl[aa1a5107c9e4d916]::run_compiler::{closure#1}>::{closure#0}, core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[93f4c45d685c579b]::result::Result<(), rustc_span[3a8ff7714ec0cd56]::ErrorGuaranteed>>::{closure#1} as core[93f4c45d685c579b]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  39:     0x7f1427773793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb296ec1752427222
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/alloc/src/boxed.rs:1988:9
  40:     0x7f1427773793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha3d23d73a848aedf
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/alloc/src/boxed.rs:1988:9
  41:     0x7f1427773793 - std::sys::unix::thread::Thread::new::thread_start::hdf09fab72a35a799
                               at /rustc/1716932743a7b3705cbf0c34db0c4e070ed1930d/library/std/src/sys/unix/thread.rs:108:17
  42:     0x7f1427505bb5 - <unknown>
  43:     0x7f1427587d90 - <unknown>
  44:                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 1.70.0-nightly (171693274 2023-03-14) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `move_into_fnmut`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 6 previous errors

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

[matthiaskrgr]

searched toolchains 0950848 through 1286ee2

---

Regression in 452cf4f

---

[bwmf2]

Alternative:

enum Either {
    One(X),
    Two(X),
}

struct X;

fn move_into_fnmut() {
    let x = Either::One(X);

    _ = || {
        let Either::Two(a) = x;
        let Either::One(b) = x;
    };
}

As long as the variants for a and b are different.

[langston-barrett]

@rustbot label +S-bug-has-mcve

[chenyukang]

Alternative:

enum Either {
    One(X),
    Two(X),
}

struct X;

fn move_into_fnmut() {
    let x = Either::One(X);

    _ = || {
        let Either::Two(a) = x;
        let Either::One(b) = x;
    };
}

As long as the variants for a and b are different.

This ICE caused by different root cause.