Broken MIR in DropGlue, Transmute is not supported in non-runtime phase Analysis(PostCleanup)

[saethlin]

I'm seeing the same ICE in about 70 crates. I should really build in some system to find the smallest one.

One of them that looks decently small is https://github.com/vmenge/speare, on commit 87f6a29f91ca60f17d6f9ed5757280a3bf73ffea if I run RUSTFLAGS=-Zvalidate-mir cargo +nightly build --tests I will get this ICE:

thread 'rustc' panicked at compiler/rustc_mir_transform/src/validate.rs:80:25:
broken MIR in DropGlue(DefId(2:2919 ~ core[74f8]::ptr::drop_in_place), Some(Coroutine(DefId(22:235 ~ speare[6d99]::spawn::{closure#0}), [one_for_all::Dad, one_for_all::Dad, (), std::future::ResumeTy, (), (), CoroutineWitness(DefId(22:235 ~ speare[6d99]::spawn::{closure#0}), [one_for_all::Dad, one_for_all::Dad]), (std::option::Option<std::time::Duration>, speare::Ctx<one_for_all::Dad>)]))) (after pass MentionedItems) at bb191[0]:
Transmute is not supported in non-runtime phase Analysis(PostCleanup).
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: <rustc_mir_transform::validate::CfgChecker>::fail::<alloc::string::String>
   3: <rustc_mir_transform::validate::Validator as rustc_mir_transform::pass_manager::MirPass>::run_pass
   4: rustc_mir_transform::pass_manager::validate_body
   5: rustc_mir_transform::pass_manager::run_passes_inner
   6: rustc_mir_transform::shim::make_shim
      [... omitted 3 frames ...]
   7: <rustc_middle::ty::context::TyCtxt>::instance_mir
   8: rustc_monomorphize::mono_checks::check_mono_item
      [... omitted 1 frame ...]
   9: rustc_monomorphize::collector::items_of_instance
      [... omitted 1 frame ...]
  10: rustc_monomorphize::collector::collect_items_rec::{closure#0}
  11: rustc_monomorphize::collector::collect_items_rec
  12: rustc_monomorphize::collector::collect_items_rec
  13: rustc_monomorphize::collector::collect_items_rec
  14: rustc_monomorphize::collector::collect_items_rec
  15: rustc_monomorphize::collector::collect_items_rec
  16: rustc_monomorphize::collector::collect_items_rec
  17: rustc_monomorphize::collector::collect_items_rec
  18: rustc_monomorphize::collector::collect_items_rec
  19: rustc_monomorphize::collector::collect_items_rec
  20: rustc_monomorphize::collector::collect_items_rec
  21: rustc_monomorphize::partitioning::collect_and_partition_mono_items
      [... omitted 2 frames ...]
  22: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  23: <rustc_interface::queries::Linker>::codegen_and_build_linker
  24: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  25: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 1.88.0-nightly (d2b3dd7c1 2025-04-11) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED] -Z validate-mir

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [mir_shims] generating MIR shim for `core::ptr::drop_in_place`
#1 [check_mono_item] monomorphization-time checking
#2 [items_of_instance] collecting items used by `core::ptr::drop_in_place::<{async block@speare::spawn<one_for_all::Dad, one_for_all::Dad>::{closure#0}}> - shim(Some({async block@speare::spawn<one_for_all::Dad, one_for_all::Dad>::{closure#0}}))`
#3 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack

[saethlin]

Bisects to #137112 cc @scottmcm

[saethlin]

Ah it seems this was predicted in the PR that added the validation that is now failing (I've unresolved the conversation so that this link works properly): https://github.com/rust-lang/rust/pull/108442/files#r1118186993

[scottmcm]

Dup of #137243 ?