[ICE]: Broken MIR: Box<dyn …$T…> is not a subtype of Box<dyn …$AssocTy…>: No solution

[wxie7]

Code

trait Transform {
    type Output<'a>;
}
trait Propagate<Input> {}
fn new_node<T: Transform>(_c: Vec<Box<dyn for<'a> Propagate<<T as Transform>::Output<'a>>>>) -> T {
    todo!()
}
impl<Input, T> Propagate<Input> for T {}
struct Noop;
impl Transform for Noop {
    type Output<'a> = ();
}
fn main() {
    let _node: Noop = new_node(vec![Box::new(Noop)]);
}

Affected release channels

• Previous Stable
• Current Stable
• Current Beta
• Current Nightly

Rust Version

rustc 1.84.0-nightly (bc5cf99 2024-11-05)
binary: rustc
commit-hash: bc5cf99
commit-date: 2024-11-05
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Current error output

note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: broken MIR in DefId(0:19 ~ w1[18d0]::main) ([move _9]): std::boxed::Box<dyn [Binder { value: Trait(Propagate<()>), bound_vars: [Region(BrNamed(DefId(0:10 ~ w1[18d0]::new_node::'a), 'a))] }] + '?13, std::alloc::Global> is not a subtype of std::boxed::Box<dyn [Binder { value: Trait(Propagate<<Noop as Transform>::Output<'a>>), bound_vars: [Region(BrNamed(DefId(0:10 ~ w1[18d0]::new_node::'a), 'a))] }] + '?6, std::alloc::Global>: NoSolution
  --> w1.rs:14:32
   |
14 |     let _node: Noop = new_node(vec![Box::new(Noop)]);
   |                                ^^^^^^^^^^^^^^^^^^^^
   |

Backtrace

note: delayed at compiler/rustc_borrowck/src/type_check/mod.rs:2575:17
     0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
     1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
     2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
     3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
     4: <rustc_borrowck::type_check::TypeChecker>::typeck_mir
     5: rustc_borrowck::type_check::type_check
     6: rustc_borrowck::nll::compute_regions
     7: rustc_borrowck::do_mir_borrowck
     8: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
     9: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
    10: rustc_query_impl::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
    11: rustc_interface::passes::run_required_analyses
    12: rustc_interface::passes::analysis
    13: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
    14: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
    15: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
    16: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
    17: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
    18: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
    19: std::sys::pal::unix::thread::Thread::new::thread_start
    20: start_thread
               at ./nptl/pthread_create.c:442:8
    21: __GI___clone3
               at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

Anything else?

note: compiler flags: --crate-type staticlib -C link-dead-code -C debuginfo=2 -C opt-level=3 -Z mir-opt-level=3 (fmease: unnecessary)

[matthiaskrgr]

the code is from #130524 (comment) , duplicate