[ICE]: Broken MIR in drop glue with specialization

# This requires `-Zvalidate-mir`

### Code

```Rust
#![feature(specialization)]

pub(crate) trait SpecTrait {
    type Assoc;
}

impl<C> SpecTrait for C {
    default type Assoc = Vec<Self>;
}

pub(crate) struct AssocWrap<C: SpecTrait> {
    _assoc: C::Assoc,
}

fn instantiate<C: SpecTrait>() -> AssocWrap<C> {
    loop {}
}

pub fn trigger() {
    instantiate::<()>();
}
```


### Affected release channels

- [ ] Previous Stable
- [ ] Current Stable
- [ ] Current Beta
- [X] Current Nightly

### Rust Version

```Shell
rustc 1.69.0-nightly (5e37043d6 2023-01-22)
binary: rustc
commit-hash: 5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d
commit-date: 2023-01-22
host: x86_64-unknown-linux-gnu
release: 1.69.0-nightly
LLVM version: 15.0.7
```


### Current error output

```Shell
error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: broken MIR in DropGlue(DefId(2:2154 ~ core[df84]::ptr::drop_in_place), Some(AssocWrap<()>)) (before pass AddMovesForPackedDrops) at bb4[0]:
                                Field projection `(*_1).field[0]` specified type `std::vec::Vec<()>`, but actual type is `<() as SpecTrait>::Assoc`
```


### Backtrace

```Shell
warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
 --> aa.rs:1:12
  |
1 | #![feature(specialization)]
  |            ^^^^^^^^^^^^^^
  |
  = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
  = help: consider using `min_specialization` instead, which is more stable and complete
  = note: `#[warn(incomplete_features)]` on by default

warning: 1 warning emitted

error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: broken MIR in DropGlue(DefId(2:2154 ~ core[df84]::ptr::drop_in_place), Some(AssocWrap<()>)) (before pass AddMovesForPackedDrops) at bb4[0]:
                                Field projection `(*_1).field[0]` specified type `std::vec::Vec<()>`, but actual type is `<() as SpecTrait>::Assoc`
   --> /home/nilsh/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:490:1
    |
490 | pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: delayed at    0: <rustc_errors::HandlerInner>::emit_diagnostic
               1: <rustc_errors::Handler>::delay_span_bug::<rustc_span::span_encoding::Span, &alloc::string::String>
               2: <rustc_const_eval::transform::validate::TypeChecker>::fail::<alloc::string::String>
               3: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_place
               4: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_terminator
               5: <rustc_const_eval::transform::validate::Validator as rustc_middle::mir::MirPass>::run_pass
               6: rustc_mir_transform::pass_manager::validate_body
               7: rustc_mir_transform::pass_manager::run_passes_inner
               8: rustc_mir_transform::shim::make_shim
               9: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::mir_shims, rustc_query_impl::plumbing::QueryCtxt>
              10: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::mir_shims
              11: <rustc_middle::ty::context::TyCtxt>::instance_mir
              12: rustc_monomorphize::collector::collect_neighbours
              13: rustc_monomorphize::collector::collect_items_rec
              14: rustc_monomorphize::collector::collect_items_rec
              15: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
              16: rustc_monomorphize::collector::collect_crate_mono_items
              17: rustc_monomorphize::partitioning::collect_and_partition_mono_items
              18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::collect_and_partition_mono_items, rustc_query_impl::plumbing::QueryCtxt>
              19: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items
              20: rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local
              21: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt>
              22: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt, rustc_middle::dep_graph::dep_node::DepKind>
              23: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
              24: rustc_metadata::rmeta::encoder::encode_metadata_impl
              25: rustc_data_structures::sync::join::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>
              26: rustc_metadata::rmeta::encoder::encode_metadata
              27: rustc_metadata::fs::encode_and_write_metadata
              28: rustc_interface::passes::start_codegen
              29: <rustc_interface::queries::Queries>::ongoing_codegen
              30: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
              31: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              32: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              33: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
              34: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              35: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              36: std::sys::unix::thread::Thread::new::thread_start
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/std/src/sys/unix/thread.rs:108:17
              37: start_thread
                         at ./nptl/./nptl/pthread_create.c:442:8
              38: clone3
                         at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81


error: internal compiler error: broken MIR in DropGlue(DefId(2:2154 ~ core[df84]::ptr::drop_in_place), Some(AssocWrap<()>)) (before pass AddMovesForPackedDrops) at bb5[0]:
                                Field projection `(*_1).field[0]` specified type `std::vec::Vec<()>`, but actual type is `<() as SpecTrait>::Assoc`
   --> /home/nilsh/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:490:1
    |
490 | pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: delayed at    0: <rustc_errors::HandlerInner>::emit_diagnostic
               1: <rustc_errors::Handler>::delay_span_bug::<rustc_span::span_encoding::Span, &alloc::string::String>
               2: <rustc_const_eval::transform::validate::TypeChecker>::fail::<alloc::string::String>
               3: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_place
               4: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_terminator
               5: <rustc_const_eval::transform::validate::Validator as rustc_middle::mir::MirPass>::run_pass
               6: rustc_mir_transform::pass_manager::validate_body
               7: rustc_mir_transform::pass_manager::run_passes_inner
               8: rustc_mir_transform::shim::make_shim
               9: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::mir_shims, rustc_query_impl::plumbing::QueryCtxt>
              10: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::mir_shims
              11: <rustc_middle::ty::context::TyCtxt>::instance_mir
              12: rustc_monomorphize::collector::collect_neighbours
              13: rustc_monomorphize::collector::collect_items_rec
              14: rustc_monomorphize::collector::collect_items_rec
              15: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
              16: rustc_monomorphize::collector::collect_crate_mono_items
              17: rustc_monomorphize::partitioning::collect_and_partition_mono_items
              18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::collect_and_partition_mono_items, rustc_query_impl::plumbing::QueryCtxt>
              19: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items
              20: rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local
              21: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt>
              22: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt, rustc_middle::dep_graph::dep_node::DepKind>
              23: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
              24: rustc_metadata::rmeta::encoder::encode_metadata_impl
              25: rustc_data_structures::sync::join::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>
              26: rustc_metadata::rmeta::encoder::encode_metadata
              27: rustc_metadata::fs::encode_and_write_metadata
              28: rustc_interface::passes::start_codegen
              29: <rustc_interface::queries::Queries>::ongoing_codegen
              30: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
              31: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              32: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              33: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
              34: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              35: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              36: std::sys::unix::thread::Thread::new::thread_start
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/std/src/sys/unix/thread.rs:108:17
              37: start_thread
                         at ./nptl/./nptl/pthread_create.c:442:8
              38: clone3
                         at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81


......



error: internal compiler error: broken MIR in DropGlue(DefId(2:2154 ~ core[df84]::ptr::drop_in_place), Some(AssocWrap<()>)) (after pass AbortUnwindingCalls) at bb0[0]:
                                Field projection `(*_1).field[0]` specified type `std::vec::Vec<()>`, but actual type is `<() as SpecTrait>::Assoc`
   --> /home/nilsh/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:490:1
    |
490 | pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: delayed at    0: <rustc_errors::HandlerInner>::emit_diagnostic
               1: <rustc_errors::Handler>::delay_span_bug::<rustc_span::span_encoding::Span, &alloc::string::String>
               2: <rustc_const_eval::transform::validate::TypeChecker>::fail::<alloc::string::String>
               3: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_place
               4: <rustc_const_eval::transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_terminator
               5: <rustc_const_eval::transform::validate::Validator as rustc_middle::mir::MirPass>::run_pass
               6: rustc_mir_transform::pass_manager::validate_body
               7: rustc_mir_transform::pass_manager::run_passes_inner
               8: rustc_mir_transform::shim::make_shim
               9: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::mir_shims, rustc_query_impl::plumbing::QueryCtxt>
              10: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::mir_shims
              11: <rustc_middle::ty::context::TyCtxt>::instance_mir
              12: rustc_monomorphize::collector::collect_neighbours
              13: rustc_monomorphize::collector::collect_items_rec
              14: rustc_monomorphize::collector::collect_items_rec
              15: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
              16: rustc_monomorphize::collector::collect_crate_mono_items
              17: rustc_monomorphize::partitioning::collect_and_partition_mono_items
              18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::collect_and_partition_mono_items, rustc_query_impl::plumbing::QueryCtxt>
              19: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items
              20: rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local
              21: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt>
              22: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt, rustc_middle::dep_graph::dep_node::DepKind>
              23: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
              24: rustc_metadata::rmeta::encoder::encode_metadata_impl
              25: rustc_data_structures::sync::join::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>
              26: rustc_metadata::rmeta::encoder::encode_metadata
              27: rustc_metadata::fs::encode_and_write_metadata
              28: rustc_interface::passes::start_codegen
              29: <rustc_interface::queries::Queries>::ongoing_codegen
              30: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
              31: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              32: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
              33: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
              34: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              35: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/alloc/src/boxed.rs:1988:9
              36: std::sys::unix::thread::Thread::new::thread_start
                         at /rustc/5e37043d63bfe2f3be8fa5a05b07d6c0dad5775d/library/std/src/sys/unix/thread.rs:108:17
              37: start_thread
                         at ./nptl/./nptl/pthread_create.c:442:8
              38: clone3
                         at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81


note: 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 1.69.0-nightly (5e37043d6 2023-01-22) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib -Z validate-mir

query stack during panic:
end of query stack
```


### Anything else?

This requires `-Zvalidate-mir`!

Minimized out of #107051

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[ICE]: Broken MIR in drop glue with specialization #107228

Noratrieb
openedon Jan 23, 2023

This requires `-Zvalidate-mir`

Code

Affected release channels

Rust Version

Current error output

Backtrace

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