Repository: rust
Issue: ICE: `FloatToFloat/FloatToInt cast: source type usize is not a float type`
Labels: I-ICE,T-compiler,C-bug,F-generic_const_exprs,S-has-mcve,S-bug-has-test,requires-incomplete-features

<!--
[31mICE[0m: Rustc ./ice.rs '' 'error: internal compiler error: compiler/rustc_const_eval/src/interpret/cast.rs:189:13: FloatToFloat/FloatToInt cast: source type usize is not a float type', 'error: internal compiler error: compiler/rustc_const_eval/src/interpret/cast.rs:189:13: FloatToFloat/FloatToInt cast: source type usize is not a float type'
File: /tmp/im/ice.rs
-->

snippet:
````rust
#![feature(generic_const_exprs)]

trait Trait {}

struct HasCastInTraitImpl<const N: usize, const M: u128>;
impl<const O: f64> Trait for HasCastInTraitImpl<O, { O as u128 }> {}

pub fn use_trait_impl() {
    fn assert_impl<T: Trait>() {}

    assert_impl::<HasCastInTraitImpl<13, 13>>();
}


````

Version information
````
rustc 1.80.0-nightly (32a3ed229 2024-05-30)
binary: rustc
commit-hash: 32a3ed229caaaa6476ee1b0e644dd53579454536
commit-date: 2024-05-30
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.6

````

Command:
`/home/matthias/.rustup/toolchains/master/bin/rustc `

<!--
Include a backtrace in the code block by setting `RUST_BACKTRACE=1` in your
environment. E.g. `RUST_BACKTRACE=1 cargo build`.
-->
<details><summary><strong>Program output</strong></summary>
<p>

```
warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:1:12
  |
1 | #![feature(generic_const_exprs)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:12:2
   |
12 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs`

error: the constant `O` is not of type `usize`
 --> /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:6:30
  |
6 | impl<const O: f64> Trait for HasCastInTraitImpl<O, { O as u128 }> {}
  |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `usize`, found `f64`
  |
note: required by a bound in `HasCastInTraitImpl`
 --> /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:5:27
  |
5 | struct HasCastInTraitImpl<const N: usize, const M: u128>;
  |                           ^^^^^^^^^^^^^^ required by this bound in `HasCastInTraitImpl`

error: `f64` is forbidden as the type of a const generic parameter
 --> /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:6:15
  |
6 | impl<const O: f64> Trait for HasCastInTraitImpl<O, { O as u128 }> {}
  |               ^^^
  |
  = note: the only supported types are integers, `bool` and `char`

error: internal compiler error: compiler/rustc_const_eval/src/interpret/cast.rs:189:13: FloatToFloat/FloatToInt cast: source type usize is not a float type

thread 'rustc' panicked at compiler/rustc_const_eval/src/interpret/cast.rs:189:13:
Box<dyn Any>
stack backtrace:
   0:     0x7b9afb23ccc5 - std::backtrace_rs::backtrace::libunwind::trace::h678682a49ad9b996
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:     0x7b9afb23ccc5 - std::backtrace_rs::backtrace::trace_unsynchronized::hee6fa95bb2553111
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7b9afb23ccc5 - std::sys_common::backtrace::_print_fmt::h95e0b5b079a7d050
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7b9afb23ccc5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h5ef0519e3348f4b3
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7b9afb28d6bb - core::fmt::rt::Argument::fmt::h351d794db9ebf8d4
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/core/src/fmt/rt.rs:165:63
   5:     0x7b9afb28d6bb - core::fmt::write::hf6a10f4e291514d0
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/core/src/fmt/mod.rs:1168:21
   6:     0x7b9afb23199f - std::io::Write::write_fmt::h3774e539b39c6176
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/io/mod.rs:1835:15
   7:     0x7b9afb23ca9e - std::sys_common::backtrace::_print::h0766b9d4e4e1a2a5
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7b9afb23ca9e - std::sys_common::backtrace::print::hf85a15b68fc127ec
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7b9afb23f4d9 - std::panicking::default_hook::{{closure}}::hba9aa02e8bae00f0
  10:     0x7b9afb23f27a - std::panicking::default_hook::h1795c37d9b50a345
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/panicking.rs:298:9
  11:     0x7b9af7940d00 - std[fbc7945dfe4e847c]::panicking::update_hook::<alloc[648a2435367f9e21]::boxed::Box<rustc_driver_impl[4c120566f3914dcc]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7b9afb23fc0b - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hb26c638276518655
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/alloc/src/boxed.rs:2077:9
  13:     0x7b9afb23fc0b - std::panicking::rust_panic_with_hook::h9450536fa6827029
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/panicking.rs:799:13
  14:     0x7b9af7970de4 - std[fbc7945dfe4e847c]::panicking::begin_panic::<rustc_errors[29c2300d656916ab]::ExplicitBug>::{closure#0}
  15:     0x7b9af796d9e6 - std[fbc7945dfe4e847c]::sys_common::backtrace::__rust_end_short_backtrace::<std[fbc7945dfe4e847c]::panicking::begin_panic<rustc_errors[29c2300d656916ab]::ExplicitBug>::{closure#0}, !>
  16:     0x7b9af796d6c6 - std[fbc7945dfe4e847c]::panicking::begin_panic::<rustc_errors[29c2300d656916ab]::ExplicitBug>
  17:     0x7b9af797a261 - <rustc_errors[29c2300d656916ab]::diagnostic::BugAbort as rustc_errors[29c2300d656916ab]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7b9af7e6827c - rustc_middle[be94168a967605d5]::util::bug::opt_span_bug_fmt::<rustc_span[41e37a1bb73e38bc]::span_encoding::Span>::{closure#0}
  19:     0x7b9af7e4ad7a - rustc_middle[be94168a967605d5]::ty::context::tls::with_opt::<rustc_middle[be94168a967605d5]::util::bug::opt_span_bug_fmt<rustc_span[41e37a1bb73e38bc]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x7b9af7e4ac1b - rustc_middle[be94168a967605d5]::ty::context::tls::with_context_opt::<rustc_middle[be94168a967605d5]::ty::context::tls::with_opt<rustc_middle[be94168a967605d5]::util::bug::opt_span_bug_fmt<rustc_span[41e37a1bb73e38bc]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x7b9af618e150 - rustc_middle[be94168a967605d5]::util::bug::bug_fmt
  22:     0x7b9af98c33eb - <rustc_const_eval[d725f5dd974c28ec]::interpret::eval_context::InterpCx<rustc_const_eval[d725f5dd974c28ec]::const_eval::machine::CompileTimeInterpreter>>::eval_rvalue_into_place
  23:     0x7b9af6d37a4d - rustc_const_eval[d725f5dd974c28ec]::const_eval::eval_queries::eval_to_allocation_raw_provider
  24:     0x7b9af93b763c - rustc_query_impl[c0e0181520bdf354]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c0e0181520bdf354]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>
  25:     0x7b9af93b6e59 - rustc_query_system[a635211d769013fd]::query::plumbing::try_execute_query::<rustc_query_impl[c0e0181520bdf354]::DynamicConfig<rustc_query_system[a635211d769013fd]::query::caches::DefaultCache<rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[c0e0181520bdf354]::plumbing::QueryCtxt, false>
  26:     0x7b9af93b6a30 - rustc_query_impl[c0e0181520bdf354]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  27:     0x7b9af9b6aaf6 - rustc_middle[be94168a967605d5]::query::plumbing::query_get_at::<rustc_query_system[a635211d769013fd]::query::caches::DefaultCache<rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>>
  28:     0x7b9af9b6adb5 - rustc_const_eval[d725f5dd974c28ec]::const_eval::valtrees::eval_to_valtree
  29:     0x7b9af9b6ad49 - <rustc_const_eval[d725f5dd974c28ec]::provide::{closure#0} as core[6d46e2ae36dee942]::ops::function::FnOnce<(rustc_middle[be94168a967605d5]::ty::context::TyCtxt, rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>)>>::call_once
  30:     0x7b9af9b6ad00 - rustc_query_impl[c0e0181520bdf354]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c0e0181520bdf354]::query_impl::eval_to_valtree::dynamic_query::{closure#2}::{closure#0}, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>
  31:     0x7b9af9b6acc1 - <rustc_query_impl[c0e0181520bdf354]::query_impl::eval_to_valtree::dynamic_query::{closure#2} as core[6d46e2ae36dee942]::ops::function::FnOnce<(rustc_middle[be94168a967605d5]::ty::context::TyCtxt, rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>)>>::call_once
  32:     0x7b9af93b6f34 - rustc_query_system[a635211d769013fd]::query::plumbing::try_execute_query::<rustc_query_impl[c0e0181520bdf354]::DynamicConfig<rustc_query_system[a635211d769013fd]::query::caches::DefaultCache<rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[c0e0181520bdf354]::plumbing::QueryCtxt, false>
  33:     0x7b9af93b6858 - rustc_query_impl[c0e0181520bdf354]::query_impl::eval_to_valtree::get_query_non_incr::__rust_end_short_backtrace
  34:     0x7b9af97c86f1 - rustc_middle[be94168a967605d5]::query::plumbing::query_get_at::<rustc_query_system[a635211d769013fd]::query::caches::DefaultCache<rustc_middle[be94168a967605d5]::ty::ParamEnvAnd<rustc_middle[be94168a967605d5]::mir::interpret::GlobalId>, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 24usize]>>>
  35:     0x7b9af98e0bf3 - <rustc_middle[be94168a967605d5]::ty::context::TyCtxt>::const_eval_global_id_for_typeck
  36:     0x7b9af98e11c2 - <rustc_middle[be94168a967605d5]::ty::context::TyCtxt>::const_eval_resolve_for_typeck
  37:     0x7b9af7ca0162 - <rustc_infer[94dcf74a7bd108a5]::infer::InferCtxt>::const_eval_resolve
  38:     0x7b9afa6bde47 - rustc_trait_selection[294db240007bd44b]::traits::const_evaluatable::is_const_evaluatable.cold
  39:     0x7b9af58eb8d3 - <rustc_trait_selection[294db240007bd44b]::traits::fulfill::FulfillProcessor as rustc_data_structures[db4c5959faeb11bb]::obligation_forest::ObligationProcessor>::process_obligation
  40:     0x7b9af8e05cf6 - <rustc_data_structures[db4c5959faeb11bb]::obligation_forest::ObligationForest<rustc_trait_selection[294db240007bd44b]::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection[294db240007bd44b]::traits::fulfill::FulfillProcessor>
  41:     0x7b9af5a5bc99 - <rustc_hir_typeck[27bfc99261d6777a]::fn_ctxt::FnCtxt>::confirm_builtin_call
  42:     0x7b9af97e9f77 - <rustc_hir_typeck[27bfc99261d6777a]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  43:     0x7b9af97e57f3 - <rustc_hir_typeck[27bfc99261d6777a]::fn_ctxt::FnCtxt>::check_block_with_expected
  44:     0x7b9af97ea937 - <rustc_hir_typeck[27bfc99261d6777a]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  45:     0x7b9af919e0d4 - rustc_hir_typeck[27bfc99261d6777a]::check::check_fn
  46:     0x7b9af919386c - rustc_hir_typeck[27bfc99261d6777a]::typeck
  47:     0x7b9af91932d1 - rustc_query_impl[c0e0181520bdf354]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c0e0181520bdf354]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 8usize]>>
  48:     0x7b9af905a86e - rustc_query_system[a635211d769013fd]::query::plumbing::try_execute_query::<rustc_query_impl[c0e0181520bdf354]::DynamicConfig<rustc_query_system[a635211d769013fd]::query::caches::VecCache<rustc_span[41e37a1bb73e38bc]::def_id::LocalDefId, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[c0e0181520bdf354]::plumbing::QueryCtxt, false>
  49:     0x7b9af9059395 - rustc_query_impl[c0e0181520bdf354]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  50:     0x7b9af9058fcb - <rustc_middle[be94168a967605d5]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[9feabfd3ed563fae]::check_crate::{closure#4}>::{closure#0}
  51:     0x7b9af9057a8b - rustc_hir_analysis[9feabfd3ed563fae]::check_crate
  52:     0x7b9af98275fe - rustc_interface[c870be2efde3492c]::passes::analysis
  53:     0x7b9af982715b - rustc_query_impl[c0e0181520bdf354]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c0e0181520bdf354]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 1usize]>>
  54:     0x7b9af9b8f725 - rustc_query_system[a635211d769013fd]::query::plumbing::try_execute_query::<rustc_query_impl[c0e0181520bdf354]::DynamicConfig<rustc_query_system[a635211d769013fd]::query::caches::SingleCache<rustc_middle[be94168a967605d5]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[c0e0181520bdf354]::plumbing::QueryCtxt, false>
  55:     0x7b9af9b8f48f - rustc_query_impl[c0e0181520bdf354]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  56:     0x7b9af9a2120e - rustc_interface[c870be2efde3492c]::interface::run_compiler::<core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>, rustc_driver_impl[4c120566f3914dcc]::run_compiler::{closure#0}>::{closure#1}
  57:     0x7b9af99e23c9 - std[fbc7945dfe4e847c]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[c870be2efde3492c]::util::run_in_thread_with_globals<rustc_interface[c870be2efde3492c]::util::run_in_thread_pool_with_globals<rustc_interface[c870be2efde3492c]::interface::run_compiler<core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>, rustc_driver_impl[4c120566f3914dcc]::run_compiler::{closure#0}>::{closure#1}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>::{closure#0}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>
  58:     0x7b9af99e2172 - <<std[fbc7945dfe4e847c]::thread::Builder>::spawn_unchecked_<rustc_interface[c870be2efde3492c]::util::run_in_thread_with_globals<rustc_interface[c870be2efde3492c]::util::run_in_thread_pool_with_globals<rustc_interface[c870be2efde3492c]::interface::run_compiler<core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>, rustc_driver_impl[4c120566f3914dcc]::run_compiler::{closure#0}>::{closure#1}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>::{closure#0}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[6d46e2ae36dee942]::result::Result<(), rustc_span[41e37a1bb73e38bc]::ErrorGuaranteed>>::{closure#2} as core[6d46e2ae36dee942]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  59:     0x7b9afb249bfb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h5d22407a994a8dd7
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/alloc/src/boxed.rs:2063:9
  60:     0x7b9afb249bfb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he08091f4f7e587cf
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/alloc/src/boxed.rs:2063:9
  61:     0x7b9afb249bfb - std::sys::pal::unix::thread::Thread::new::thread_start::h4ffcec4576023b2b
                               at /rustc/32a3ed229caaaa6476ee1b0e644dd53579454536/library/std/src/sys/pal/unix/thread.rs:108:17
  62:     0x7b9af46aa1cf - <unknown>
  63:     0x7b9af472b6ec - <unknown>
  64:                0x0 - <unknown>

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 1.80.0-nightly (32a3ed229 2024-05-30) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [eval_to_allocation_raw] const-evaluating + checking `<impl at /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:6:1: 6:66>::{constant#0}`
#1 [eval_to_valtree] evaluating type-level constant
end of query stack
error: aborting due to 4 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0601`.

```

</p>
</details>

<!--
query stack:
#0 [eval_to_allocation_raw] const-evaluating + checking `<impl at /tmp/icemaker_global_tempdir.24ZAkKJT8e2J/rustc_testrunner_tmpdir_reporting.OPFOglKdOJxp/mvce.rs:6:1: 6:66>::{constant#0}`
#1 [eval_to_valtree] evaluating type-level constant

-->
@rustbot label +F-generic_const_exprs