ICE: should be handled by `coerce`

auto-reduced (treereduce-rust):

#![feature(dyn_star)]

trait Trait {}

fn main() {
    let x: dyn* Trait + Send = 1usize;
    x as dyn* Trait;
}

original:

#![allow(incomplete_features)]
#![feature(dyn_star)]

trait Trait {}
impl Trait for usize {}

fn main() {
    // We allow &dyn Trait + Send -> &dyn Send (i.e. dropping principal),
    // but we don't (currently?) allow the same for dyn*
    let x: dyn* Trait + Send = 1usize;
    x as dyn* Trait; //~ error: `dyn* Trait + Send` needs to have the same ABI as a pointer
}

Version information

rustc 1.84.0-nightly (788202a2c 2024-10-25)
binary: rustc
commit-hash: 788202a2cef5dde0743490fd51515f373d4207a6
commit-date: 2024-10-25
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.1

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

Program output

``` warning: the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes --> /tmp/icemaker_global_tempdir.CwzM23YOfQY1/rustc_testrunner_tmpdir_reporting.Lix3JMAxVVt9/mvce.rs:1:12 | 1 | #![feature(dyn_star)] | ^^^^^^^^ | = note: see issue #102425 for more information = note: `#[warn(incomplete_features)]` on by default error[E0277]: the trait bound `usize: Trait` is not satisfied --> /tmp/icemaker_global_tempdir.CwzM23YOfQY1/rustc_testrunner_tmpdir_reporting.Lix3JMAxVVt9/mvce.rs:6:32 | 6 | let x: dyn* Trait + Send = 1usize; | ^^^^^^ the trait `Trait` is not implemented for `usize` | help: this trait has no implementations, consider adding one --> /tmp/icemaker_global_tempdir.CwzM23YOfQY1/rustc_testrunner_tmpdir_reporting.Lix3JMAxVVt9/mvce.rs:3:1 | 3 | trait Trait {} | ^^^^^^^^^^^ error: internal compiler error: compiler/rustc_hir_typeck/src/cast.rs:725:17: should be handled by `coerce` --> /tmp/icemaker_global_tempdir.CwzM23YOfQY1/rustc_testrunner_tmpdir_reporting.Lix3JMAxVVt9/mvce.rs:7:5 | 7 | x as dyn* Trait; | ^^^^^^^^^^^^^^^ thread 'rustc' panicked at compiler/rustc_hir_typeck/src/cast.rs:725:17: Box stack backtrace: 0: 0x7394ab49d63a - ::fmt::h5e8099de960d4cc6 1: 0x7394abc041ca - core::fmt::write::hf87b533eacaf516a 2: 0x7394acea72d1 - std::io::Write::write_fmt::hb58c604a9dfe85f1 3: 0x7394ab49d492 - std::sys::backtrace::BacktraceLock::print::h922a09e37c27473c 4: 0x7394ab49f996 - std::panicking::default_hook::{{closure}}::ha4ce1ceabb39d9dc 5: 0x7394ab49f7e0 - std::panicking::default_hook::hdbfa0836e0b339ee 6: 0x7394aa51d2ef - std[a585c2783b39f442]::panicking::update_hook::>::{closure#0} 7: 0x7394ab4a00a8 - std::panicking::rust_panic_with_hook::h87bc2ca479f0c940 8: 0x7394aa556971 - std[a585c2783b39f442]::panicking::begin_panic::::{closure#0} 9: 0x7394aa549916 - std[a585c2783b39f442]::sys::backtrace::__rust_end_short_backtrace::::{closure#0}, !> 10: 0x7394aa544f19 - std[a585c2783b39f442]::panicking::begin_panic:: 11: 0x7394aa5604e1 - ::emit_producing_guarantee 12: 0x7394a91023d0 - ::span_bug:: 13: 0x7394aa7d0777 - rustc_middle[5b3bbff2208691d6]::util::bug::opt_span_bug_fmt::::{closure#0} 14: 0x7394aa7d479a - rustc_middle[5b3bbff2208691d6]::ty::context::tls::with_opt::::{closure#0}, !>::{closure#0} 15: 0x7394aa77ea4b - rustc_middle[5b3bbff2208691d6]::ty::context::tls::with_context_opt::::{closure#0}, !>::{closure#0}, !> 16: 0x7394a8a1fcc7 - rustc_middle[5b3bbff2208691d6]::util::bug::span_bug_fmt:: 17: 0x7394acd504f3 - ::do_check 18: 0x7394abfb2635 - ::check_casts 19: 0x7394abfb3a1f - rustc_hir_typeck[fef8322e73e6f38e]::typeck 20: 0x7394abfb3307 - rustc_query_impl[cf4848b6d652eea9]::plumbing::__rust_begin_short_backtrace::> 21: 0x7394abda3d81 - rustc_query_system[b2d751a8ce89225a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[cf4848b6d652eea9]::plumbing::QueryCtxt, false> 22: 0x7394abda23cd - rustc_query_impl[cf4848b6d652eea9]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace 23: 0x7394abda2047 - ::par_body_owners::::{closure#0} 24: 0x7394abd9ff1c - rustc_hir_analysis[e81663bf6ec75b26]::check_crate 25: 0x7394ac49e117 - rustc_interface[14453d2331067b08]::passes::run_required_analyses 26: 0x7394ac985a1e - rustc_interface[14453d2331067b08]::passes::analysis 27: 0x7394ac9859f1 - rustc_query_impl[cf4848b6d652eea9]::plumbing::__rust_begin_short_backtrace::> 28: 0x7394acb471ee - rustc_query_system[b2d751a8ce89225a]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[cf4848b6d652eea9]::plumbing::QueryCtxt, false> 29: 0x7394acb46ecf - rustc_query_impl[cf4848b6d652eea9]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 30: 0x7394aca265b1 - rustc_interface[14453d2331067b08]::interface::run_compiler::, rustc_driver_impl[a403acafb158cb6a]::run_compiler::{closure#0}>::{closure#1} 31: 0x7394aca996d4 - std[a585c2783b39f442]::sys::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[a403acafb158cb6a]::run_compiler::{closure#0}>::{closure#1}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>>::{closure#0}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>> 32: 0x7394aca99b0d - <::spawn_unchecked_, rustc_driver_impl[a403acafb158cb6a]::run_compiler::{closure#0}>::{closure#1}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>>::{closure#0}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[c9fb322ef39a2568]::result::Result<(), rustc_span[babd1ca03564a0eb]::ErrorGuaranteed>>::{closure#1} as core[c9fb322ef39a2568]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 33: 0x7394aca9a5ab - std::sys::pal::unix::thread::Thread::new::thread_start::h197af60b272f0d26 34: 0x7394ae2d239d - 35: 0x7394ae35749c - 36: 0x0 - 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 1.84.0-nightly (788202a2c 2024-10-25) running on x86_64-unknown-linux-gnu query stack during panic: #0 [typeck] type-checking `main` #1 [analysis] running analysis passes on this crate end of query stack error: aborting due to 2 previous errors; 1 warning emitted For more information about this error, try `rustc --explain E0277`. ```

@rustbot label +F-dyn_star

rust-lang / rust

ICE: should be handled by `coerce` #132127