//@ revisions: current next
//@ ignore-compare-mode-next-solver (explicit revisions)
//@[next] compile-flags: -Znext-solver
// We should be able to instantiate a binder during trait upcasting.
// This test could be `check-pass`, but we should make sure that we
// do so in both trait solvers.
#![feature(trait_upcasting)]
#![crate_type = "rlib"]
trait Supertrait<'a, 'b> {}
trait Subtrait<'a, 'b>: Supertrait<'a, 'b> {}
impl<'a> Supertrait<'a, 'a> for () {}
impl<'a> Subtrait<'a, 'a> for () {}
fn ok(x: &dyn for<'a, 'b> Subtrait<'a, 'b>) -> &dyn for<'a> Supertrait<'a, 'a> {
x //~ ERROR mismatched types
//[current]~^ ERROR mismatched types
}
matthiaskrgr
commented
5 hours ago
auto-reduced (treereduce-rust):
original:
Version information
Command:
/home/matthias/.rustup/toolchains/master/bin/rustcProgram output
``` warning: trait `Supertrait` is never used --> /tmp/icemaker_global_tempdir.J8Vr9e4vti8H/rustc_testrunner_tmpdir_reporting.0UEEGoO5Wkhs/mvce.rs:3:7 | 3 | trait Supertrait<'a, 'b> {} | ^^^^^^^^^^ | = note: `#[warn(dead_code)]` on by default warning: trait `Subtrait` is never used --> /tmp/icemaker_global_tempdir.J8Vr9e4vti8H/rustc_testrunner_tmpdir_reporting.0UEEGoO5Wkhs/mvce.rs:5:7 | 5 | trait Subtrait<'a, 'b>: Supertrait<'a, 'b> {} | ^^^^^^^^ warning: function `ok` is never used --> /tmp/icemaker_global_tempdir.J8Vr9e4vti8H/rustc_testrunner_tmpdir_reporting.0UEEGoO5Wkhs/mvce.rs:7:4 | 7 | fn ok(x: &dyn for<'a, 'b> Subtrait<'a, 'b>) -> &dyn for<'a> Supertrait<'a, 'a> { | ^^ thread 'rustc' panicked at compiler/rustc_trait_selection/src/traits/vtable.rs:426:77: called `Option::unwrap()` on a `None` value stack backtrace: 0: 0x7402f1ccf4ca -::fmt::h9a066335bbf3c70b
1: 0x7402f24033e6 - core::fmt::write::h4d7b6dcfa06e4b7a
2: 0x7402f35b5bd1 - std::io::Write::write_fmt::h4eb2f351153c62f5
3: 0x7402f1ccf322 - std::sys::backtrace::BacktraceLock::print::h61d14380f524de24
4: 0x7402f1cd1841 - std::panicking::default_hook::{{closure}}::hee65cb92729f1c6f
5: 0x7402f1cd1674 - std::panicking::default_hook::h10225ef2c1ae2cf5
6: 0x7402f0d9cacf - std[48a393fc970d1838]::panicking::update_hook::>::{closure#0}
7: 0x7402f1cd1f58 - std::panicking::rust_panic_with_hook::hb124b874e22ff2c5
8: 0x7402f1cd1cf6 - std::panicking::begin_panic_handler::{{closure}}::h69c13d865db3420d
9: 0x7402f1ccf979 - std::sys::backtrace::__rust_end_short_backtrace::h435b1bbccf81cd41
10: 0x7402f1cd19ec - rust_begin_unwind
11: 0x7402ef5f5bd0 - core::panicking::panic_fmt::haafd805879858244
12: 0x7402ef4357ec - core::panicking::panic::hc1dd6eb7439635bd
13: 0x7402efe0cdf9 - core::option::unwrap_failed::heaa361f2da5b5d1a
14: 0x7402f1b6e761 - rustc_trait_selection[fa1246763012ec30]::traits::vtable::supertrait_vtable_slot
15: 0x7402f17e5946 - rustc_query_impl[ec7eda03afdf420d]::plumbing::__rust_begin_short_backtrace::>
16: 0x7402f17ca559 - >::call_once
17: 0x7402f1741ddc - rustc_query_system[4eeeb108be8c1cc5]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[ec7eda03afdf420d]::plumbing::QueryCtxt, false>
18: 0x7402f18063e2 - rustc_query_impl[ec7eda03afdf420d]::query_impl::supertrait_vtable_slot::get_query_non_incr::__rust_end_short_backtrace
19: 0x7402f2a3c1b6 - rustc_codegen_ssa[3c131d82a17c56d8]::base::unsized_info::
20: 0x7402f2a3c4d1 - rustc_codegen_ssa[3c131d82a17c56d8]::base::unsize_ptr::
21: 0x7402f2a42ba9 - >::codegen_rvalue_operand
22: 0x7402f324c8fe - rustc_codegen_ssa[3c131d82a17c56d8]::mir::codegen_mir::
23: 0x7402f322d335 - rustc_codegen_llvm[808d3172d33b3fe]::base::compile_codegen_unit::module_codegen
24: 0x7402f31c9553 - ::compile_codegen_unit
25: 0x7402f31c604d - ::codegen_crate
26: 0x7402f33fc770 - ::codegen_and_build_linker
27: 0x7402f3131e8b - rustc_interface[c07a9da7023f0850]::interface::run_compiler::, rustc_driver_impl[72d45a44622a3bfe]::run_compiler::{closure#0}>::{closure#1}
28: 0x7402f31bcc10 - std[48a393fc970d1838]::sys::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[72d45a44622a3bfe]::run_compiler::{closure#0}>::{closure#1}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>::{closure#0}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>
29: 0x7402f31bd2f0 - <::spawn_unchecked_, rustc_driver_impl[72d45a44622a3bfe]::run_compiler::{closure#0}>::{closure#1}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>::{closure#0}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[a5e590a05170c700]::result::Result<(), rustc_span[28a6cfa051eff088]::ErrorGuaranteed>>::{closure#1} as core[a5e590a05170c700]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
30: 0x7402f31bd6eb - std::sys::pal::unix::thread::Thread::new::thread_start::h8fe6ba811b9bdf93
31: 0x7402f484739d -
32: 0x7402f48cc49c -
33: 0x0 -
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 1.83.0-nightly (d194948e5 2024-09-29) running on x86_64-unknown-linux-gnu
note: compiler flags: -C link-dead-code=true -Z dump-mir-dir=dir
query stack during panic:
#0 [supertrait_vtable_slot] finding the slot within vtable for trait object `dyn for<'a> Supertrait<'a, 'a>` vtable ptr during trait upcasting coercion from `dyn for<'a, 'b> Subtrait<'a, 'b>` vtable
end of query stack
warning: 3 warnings emitted
```
@rustbot label +F-trait_upcasting