rust-lang / rust-lang/rust

ICE: `FloatToFloat/FloatToInt cast: source type usize is not a float type`

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C-bug F-generic_const_exprs I-ICE P-low S-bug-has-test S-has-mcve T-compiler
Dominant language
Rust
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Description

snippet:

#![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

Program output 

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`.

@rustbot label +F-generic_const_exprs

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Research direction

Run the supplied ice.rs reproducer with rustc, then inspect compiler/rustc_const_eval/src/interpret/cast.rs around line 189 and the const-evaluation path shown in the backtrace. Done means the reproducer produces regular diagnostics without an internal compiler error or panic, with coverage for this case.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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