ICE related to f16 / f128

[tgross35]

Code

#![feature(f16, f128)]

extern "Rust" {
    pub fn foo(a: f16) -> f128;
}

fn main() {
    let a: f16 = 1.23;
    let b = unsafe { foo(a) };
}

Meta

Playground nightly version: 1.79.0-nightly (2024-03-25 5f2c7d2)

Error output

warning: unused variable: `b`
 --> src/main.rs:9:9
  |
9 |     let b = unsafe { foo(a) };
  |         ^ help: if this is intentional, prefix it with an underscore: `_b`
  |
  = note: `#[warn(unused_variables)]` on by default

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: error performing ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: UserFacing }, value: ProvePredicate { predicate: Binder { value: TraitPredicate(<f16 as std::marker::Copy>, polarity:Positive), bound_vars: [] } } }
 --> src/main.rs:9:26
  |
9 |     let b = unsafe { foo(a) };
  |                          ^
  |
note: delayed at /rustc/5f2c7d2bfd46cad00352ab7cd66242077e2e518c/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs:165:29
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxt>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_borrowck::type_check::TypeChecker>::prove_trait_ref
         4: <rustc_borrowck::type_check::TypeVerifier as rustc_middle::mir::visit::Visitor>::visit_operand
         5: <rustc_borrowck::type_check::TypeVerifier as rustc_middle::mir::visit::Visitor>::visit_body
         6: rustc_borrowck::type_check::type_check
         7: rustc_borrowck::nll::compute_regions
         8: rustc_borrowck::do_mir_borrowck
         9: rustc_borrowck::mir_borrowck
        10: 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]>>
        11: 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>
        12: rustc_query_impl::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
        13: rustc_interface::passes::analysis
        14: 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]>>
        15: 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>
        16: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        17: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}
        18: std::sys_common::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#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
        19: <<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#0}, 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}
        20: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/5f2c7d2bfd46cad00352ab7cd66242077e2e518c/library/alloc/src/boxed.rs:2015:9
        21: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/5f2c7d2bfd46cad00352ab7cd66242077e2e518c/library/alloc/src/boxed.rs:2015:9
        22: std::sys::pal::unix::thread::Thread::new::thread_start
                   at /rustc/5f2c7d2bfd46cad00352ab7cd66242077e2e518c/library/std/src/sys/pal/unix/thread.rs:108:17
        23: start_thread
        24: clone
 --> src/main.rs:9:26
  |
9 |     let b = unsafe { foo(a) };
  |                          ^

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 attach the file at `/playground/rustc-ice-2024-03-26T04_39_23-19.txt` to your bug report

note: compiler flags: --crate-type bin -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2

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

query stack during panic:
end of query stack
warning: `playground` (bin "playground") generated 1 warning
error: could not compile `playground` (bin "playground"); 1 warning emitted

This isn't expected since it doesn't seem to hit a todo!()

@rustbot label +T-compiler +f-f16_and_f128 +I-ICE +requires-incomplete-features +S-has-mcve
@rustbot claim

[tgross35]

@rustbot label -needs-triage

[fmease]

Minimized:

#![feature(f16)]
fn main() {
    let x: f16 = 1.23;
    f(x);
    fn f(_: f16) {}
}

[tgross35]

Looks like it just expects primitives to be Copy. I'm not sure where exactly this assumption comes from, but might as well fix it before the rest of libs support can get merged. #123085