ice: When Place contains ProjectionElem::Field it's type shouldn't be {type error}

[matthiaskrgr]

auto-reduced (treereduce-rust):

pub struct Foo {
    field: String,
}

pub type Tait = impl Sized;

pub async fn ice_cold(beverage: Tait) {
    let Foo { field } = beverage;
    _ = field;
}

fn main() {
    Ok(())
}

original:

// build-pass
// edition: 2021

#![feature(type_alias_impl_trait)]

pub struct Foo {
    /// This type must have nontrivial drop glue
    field: String,
}

pub type Tait = impl Sized;

pub async fn ice_cold(beverage: Tait) {
    // Must destructure at least one field of `Foo`
    let Foo { field } = beverage;
    _ = field;
}

fn main() {
    // double everything
    let mut input = vec![];
    io::stdin().read_to_end(&mut input)?;
    io::stdout().write_all(&input)?;
    io::stdout().write_all(&input)?;
    Ok(())
}

Version information

rustc 1.78.0-nightly (af88f7db5 2024-02-08)
binary: rustc
commit-hash: af88f7db51f6f2a1472f9279d7c7e7c822afff77
commit-date: 2024-02-08
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 17.0.6

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

Program output

error[E0670]: `async fn` is not permitted in Rust 2015
 --> /tmp/icemaker_global_tempdir.J2OTMscpw96F/rustc_testrunner_tmpdir_reporting.3uqeRMP0RnMp/mvce.rs:7:5
  |
7 | pub async fn ice_cold(beverage: Tait) {
  |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
  |
  = help: pass `--edition 2021` to `rustc`
  = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0658]: `impl Trait` in type aliases is unstable
 --> /tmp/icemaker_global_tempdir.J2OTMscpw96F/rustc_testrunner_tmpdir_reporting.3uqeRMP0RnMp/mvce.rs:5:17
  |
5 | pub type Tait = impl Sized;
  |                 ^^^^^^^^^^
  |
  = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
  = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
  = note: this compiler was built on 2024-02-08; consider upgrading it if it is out of date

error[E0308]: mismatched types
  --> /tmp/icemaker_global_tempdir.J2OTMscpw96F/rustc_testrunner_tmpdir_reporting.3uqeRMP0RnMp/mvce.rs:13:5
   |
12 | fn main() {
   |          - expected `()` because of default return type
13 |     Ok(())
   |     ^^^^^^ expected `()`, found `Result<(), _>`
   |
   = note: expected unit type `()`
                   found enum `Result<(), _>`

error: internal compiler error: /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/compiler/rustc_mir_dataflow/src/move_paths/builder.rs:206:45: When Place contains ProjectionElem::Field it's type shouldn't be {type error}

thread 'rustc' panicked at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/compiler/rustc_errors/src/lib.rs:922:30:
Box<dyn Any>
stack backtrace:
   0:     0x7ff6047dedd6 - std::backtrace_rs::backtrace::libunwind::trace::hf92ca961e56825b0
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7ff6047dedd6 - std::backtrace_rs::backtrace::trace_unsynchronized::h23f341cc1a6c507f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7ff6047dedd6 - std::sys_common::backtrace::_print_fmt::ha5a5ba44893edc7f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7ff6047dedd6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h667e6ba5a1d3724e
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7ff604831830 - core::fmt::rt::Argument::fmt::h06c91f49bef095fb
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/core/src/fmt/rt.rs:142:9
   5:     0x7ff604831830 - core::fmt::write::h8e4b31b0aa81d13f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/core/src/fmt/mod.rs:1120:17
   6:     0x7ff6047d264f - std::io::Write::write_fmt::h4c479f5c53dfe78c
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/io/mod.rs:1854:15
   7:     0x7ff6047debb4 - std::sys_common::backtrace::_print::he414f5864df55ed1
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7ff6047debb4 - std::sys_common::backtrace::print::h939e58bdcc61d57d
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7ff6047e1947 - std::panicking::default_hook::{{closure}}::h244e48e05cd664b2
  10:     0x7ff6047e16a9 - std::panicking::default_hook::hf842080c39497dac
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/panicking.rs:292:9
  11:     0x7ff6015454ac - std[f801e042bca9681]::panicking::update_hook::<alloc[1377227f5558ef79]::boxed::Box<rustc_driver_impl[65af58b05c4f91ef]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7ff6047e2096 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hee9c09a26ce84f59
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2029:9
  13:     0x7ff6047e2096 - std::panicking::rust_panic_with_hook::h83c20f9191a2a712
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/panicking.rs:785:13
  14:     0x7ff601576f04 - std[f801e042bca9681]::panicking::begin_panic::<rustc_errors[89ec94d63507ad05]::ExplicitBug>::{closure#0}
  15:     0x7ff6015735f6 - std[f801e042bca9681]::sys_common::backtrace::__rust_end_short_backtrace::<std[f801e042bca9681]::panicking::begin_panic<rustc_errors[89ec94d63507ad05]::ExplicitBug>::{closure#0}, !>
  16:     0x7ff60156ea66 - std[f801e042bca9681]::panicking::begin_panic::<rustc_errors[89ec94d63507ad05]::ExplicitBug>
  17:     0x7ff601582b61 - <rustc_errors[89ec94d63507ad05]::diagnostic_builder::BugAbort as rustc_errors[89ec94d63507ad05]::diagnostic_builder::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7ff6019369be - <rustc_errors[89ec94d63507ad05]::DiagCtxt>::bug::<alloc[1377227f5558ef79]::string::String>
  19:     0x7ff6019d23db - rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt::<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}
  20:     0x7ff6019b990a - rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_opt::<rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7ff6019b9788 - rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_context_opt::<rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_opt<rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7ff5ff967db0 - rustc_middle[2cc1c6e52ad3d43f]::util::bug::bug_fmt
  23:     0x7ff602f454af - <rustc_mir_dataflow[6a8aeaf0a2f9293d]::move_paths::builder::Gatherer<<rustc_mir_transform[f04df7d082cb6ded]::elaborate_drops::ElaborateDrops as rustc_middle[2cc1c6e52ad3d43f]::mir::MirPass>::run_pass::{closure#0}>>::gather_move
  24:     0x7ff6030d2465 - <rustc_mir_transform[f04df7d082cb6ded]::elaborate_drops::ElaborateDrops as rustc_middle[2cc1c6e52ad3d43f]::mir::MirPass>::run_pass
  25:     0x7ff6028123e6 - rustc_mir_transform[f04df7d082cb6ded]::pass_manager::run_passes_inner
  26:     0x7ff5ffc91352 - rustc_mir_transform[f04df7d082cb6ded]::mir_drops_elaborated_and_const_checked
  27:     0x7ff6029e3675 - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 8usize]>>
  28:     0x7ff6029e38fa - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::VecCache<rustc_span[467c297c964200f6]::def_id::LocalDefId, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  29:     0x7ff6029e31d4 - rustc_query_impl[5ca841c3c79670ea]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7ff6031d44ed - rustc_interface[c2746bee48761670]::passes::analysis
  31:     0x7ff6031d3bdf - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>
  32:     0x7ff6034a17b2 - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::SingleCache<rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  33:     0x7ff6034a1515 - rustc_query_impl[5ca841c3c79670ea]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  34:     0x7ff6034e2436 - rustc_interface[c2746bee48761670]::interface::run_compiler::<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}
  35:     0x7ff603160248 - std[f801e042bca9681]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[c2746bee48761670]::util::run_in_thread_with_globals<rustc_interface[c2746bee48761670]::util::run_in_thread_pool_with_globals<rustc_interface[c2746bee48761670]::interface::run_compiler<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>
  36:     0x7ff603160077 - <<std[f801e042bca9681]::thread::Builder>::spawn_unchecked_<rustc_interface[c2746bee48761670]::util::run_in_thread_with_globals<rustc_interface[c2746bee48761670]::util::run_in_thread_pool_with_globals<rustc_interface[c2746bee48761670]::interface::run_compiler<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#1} as core[30be359c16b30868]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  37:     0x7ff6047eb735 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h99757397e7c4fa77
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2015:9
  38:     0x7ff6047eb735 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h7e0e3d311e6447da
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2015:9
  39:     0x7ff6047eb735 - std::sys::pal::unix::thread::Thread::new::thread_start::h0eb0f22e3002fa19
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys/pal/unix/thread.rs:108:17
  40:     0x7ff5fe6aa9eb - <unknown>
  41:     0x7ff5fe72e7cc - <unknown>
  42:                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 1.78.0-nightly (af88f7db5 2024-02-08) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_drops_elaborated_and_const_checked] elaborating drops for `ice_cold::{closure#0}`
#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, E0658, E0670.
For more information about an error, try `rustc --explain E0308`.