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

[matthiaskrgr]

auto-reduced (treereduce-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>>();
}

original:

//@ check-pass
#![feature(generic_const_exprs)]
#![allow(incomplete_features)]

trait Trait {}
pub struct EvaluatableU128<const N: u128>;

struct HasCastInTraitImpl<const N: usize, const M: u128>;
impl<const O: f64> Trait for HasCastInTraitImpl<O, { O as u128 }> {}

pub fn use_trait_impl<const N: usize>() where EvaluatableU128<{N as u128}>:, {
    fn assert_impl<T: Trait>() {}

    assert_impl::<HasCastInTraitImpl<N, { N as u128 }>>();
    assert_impl::<HasCastInTraitImpl<N, { N as _ }>>();
    assert_impl::<HasCastInTraitImpl<12, { 12 as u128 }>>();
    assert_impl::<HasCastInTraitImpl<13, 13>>();
}
pub fn use_trait_impl_2<const N: usize>() where EvaluatableU128<{N as _}>:, {
    fn assert_impl<T: Trait>() {}

    assert_impl::<HasCastInTraitImpl<N, { N as u128 }>>();
    assert_impl::<HasCastInTraitImpl<N, { N as _ }>>();
    assert_impl::<HasCastInTraitImpl<12, { 12 as u128 }>>()const NUM: u8 = xyz();
    assert_impl::<HasCastInTraitImpl<13, 13>>();
}


fn main() {}

Version information

rustc 1.78.0-nightly (2ae1bb671 2024-02-24)
binary: rustc
commit-hash: 2ae1bb671183a072b54ed8ed39abfcd72990a3e7
commit-date: 2024-02-24
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

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.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/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.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/mvce.rs:12:2
   |
12 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/mvce.rs`

error: the constant `O` is not of type `usize`
 --> /tmp/icemaker_global_tempdir.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/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.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/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.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/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:190:17: Can't cast 'Float' type into u128

thread 'rustc' panicked at compiler/rustc_middle/src/util/bug.rs:35:44:
Box<dyn Any>
stack backtrace:
   0:     0x7f325cd8caf6 - std::backtrace_rs::backtrace::libunwind::trace::h78e1beabc241470d
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f325cd8caf6 - std::backtrace_rs::backtrace::trace_unsynchronized::hcf0e3276676937a9
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f325cd8caf6 - std::sys_common::backtrace::_print_fmt::h97e735845ccdd467
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f325cd8caf6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h8e5712cf7013f6fb
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f325cddda7c - core::fmt::rt::Argument::fmt::heb6e69b80afbd30f
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/core/src/fmt/rt.rs:142:9
   5:     0x7f325cddda7c - core::fmt::write::hdc6decd8b058c5bd
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f325cd8142f - std::io::Write::write_fmt::h842bc593311134e9
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/io/mod.rs:1846:15
   7:     0x7f325cd8c8a4 - std::sys_common::backtrace::_print::h943a0b890de28a0e
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f325cd8c8a4 - std::sys_common::backtrace::print::hb82258756379bede
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f325cd8f5eb - std::panicking::default_hook::{{closure}}::h19d49c5a8abcf1fa
  10:     0x7f325cd8f339 - std::panicking::default_hook::h0b641f1f8c9de2bf
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/panicking.rs:292:9
  11:     0x7f325fc8bcdc - std[1167999404bd111b]::panicking::update_hook::<alloc[530719d21e18248f]::boxed::Box<rustc_driver_impl[221cda1307b92b70]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f325cd8fd50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h9256970e3d77e3fc
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/alloc/src/boxed.rs:2030:9
  13:     0x7f325cd8fd50 - std::panicking::rust_panic_with_hook::hd08646cb5d109a5b
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/panicking.rs:783:13
  14:     0x7f325fcb87f4 - std[1167999404bd111b]::panicking::begin_panic::<rustc_errors[430cc2d97f9a0eb3]::ExplicitBug>::{closure#0}
  15:     0x7f325fcb5446 - std[1167999404bd111b]::sys_common::backtrace::__rust_end_short_backtrace::<std[1167999404bd111b]::panicking::begin_panic<rustc_errors[430cc2d97f9a0eb3]::ExplicitBug>::{closure#0}, !>
  16:     0x7f325fcb0c06 - std[1167999404bd111b]::panicking::begin_panic::<rustc_errors[430cc2d97f9a0eb3]::ExplicitBug>
  17:     0x7f325fcc21e1 - <rustc_errors[430cc2d97f9a0eb3]::diagnostic::BugAbort as rustc_errors[430cc2d97f9a0eb3]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7f326009a8bc - <rustc_errors[430cc2d97f9a0eb3]::DiagCtxt>::bug::<alloc[530719d21e18248f]::string::String>
  19:     0x7f326013f55b - rustc_middle[2fef699d51b04cde]::util::bug::opt_span_bug_fmt::<rustc_span[dca1c35612e9799e]::span_encoding::Span>::{closure#0}
  20:     0x7f3260122daa - rustc_middle[2fef699d51b04cde]::ty::context::tls::with_opt::<rustc_middle[2fef699d51b04cde]::util::bug::opt_span_bug_fmt<rustc_span[dca1c35612e9799e]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f3260122c48 - rustc_middle[2fef699d51b04cde]::ty::context::tls::with_context_opt::<rustc_middle[2fef699d51b04cde]::ty::context::tls::with_opt<rustc_middle[2fef699d51b04cde]::util::bug::opt_span_bug_fmt<rustc_span[dca1c35612e9799e]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f325e55e940 - rustc_middle[2fef699d51b04cde]::util::bug::bug_fmt
  23:     0x7f3261ef5e68 - rustc_const_eval[e5663af8bd04b20a]::const_eval::eval_queries::eval_body_using_ecx::{closure#0}
  24:     0x7f3261e76723 - rustc_const_eval[e5663af8bd04b20a]::const_eval::eval_queries::eval_in_interpreter
  25:     0x7f32613f6572 - rustc_const_eval[e5663af8bd04b20a]::const_eval::eval_queries::eval_to_allocation_raw_provider
  26:     0x7f32613f6340 - rustc_query_impl[2d7a486b3b483e50]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d7a486b3b483e50]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 24usize]>>
  27:     0x7f3261a0fed1 - rustc_query_system[cca60478b9b5cf0a]::query::plumbing::try_execute_query::<rustc_query_impl[2d7a486b3b483e50]::DynamicConfig<rustc_query_system[cca60478b9b5cf0a]::query::caches::DefaultCache<rustc_middle[2fef699d51b04cde]::ty::ParamEnvAnd<rustc_middle[2fef699d51b04cde]::mir::interpret::GlobalId>, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[2d7a486b3b483e50]::plumbing::QueryCtxt, false>
  28:     0x7f3261a0faac - rustc_query_impl[2d7a486b3b483e50]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  29:     0x7f3261a119d4 - rustc_const_eval[e5663af8bd04b20a]::const_eval::valtrees::eval_to_valtree
  30:     0x7f3261a117e2 - <rustc_const_eval[e5663af8bd04b20a]::provide::{closure#0} as core[2d5c3c55c032a2b6]::ops::function::FnOnce<(rustc_middle[2fef699d51b04cde]::ty::context::TyCtxt, rustc_middle[2fef699d51b04cde]::ty::ParamEnvAnd<rustc_middle[2fef699d51b04cde]::mir::interpret::GlobalId>)>>::call_once
  31:     0x7f3261a117b6 - rustc_query_impl[2d7a486b3b483e50]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d7a486b3b483e50]::query_impl::eval_to_valtree::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 24usize]>>
  32:     0x7f3261a11773 - <rustc_query_impl[2d7a486b3b483e50]::query_impl::eval_to_valtree::dynamic_query::{closure#2} as core[2d5c3c55c032a2b6]::ops::function::FnOnce<(rustc_middle[2fef699d51b04cde]::ty::context::TyCtxt, rustc_middle[2fef699d51b04cde]::ty::ParamEnvAnd<rustc_middle[2fef699d51b04cde]::mir::interpret::GlobalId>)>>::call_once
  33:     0x7f3261a0ffac - rustc_query_system[cca60478b9b5cf0a]::query::plumbing::try_execute_query::<rustc_query_impl[2d7a486b3b483e50]::DynamicConfig<rustc_query_system[cca60478b9b5cf0a]::query::caches::DefaultCache<rustc_middle[2fef699d51b04cde]::ty::ParamEnvAnd<rustc_middle[2fef699d51b04cde]::mir::interpret::GlobalId>, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[2d7a486b3b483e50]::plumbing::QueryCtxt, false>
  34:     0x7f3261a0f8ac - rustc_query_impl[2d7a486b3b483e50]::query_impl::eval_to_valtree::get_query_non_incr::__rust_end_short_backtrace
  35:     0x7f3261a0f0be - rustc_middle[2fef699d51b04cde]::query::plumbing::query_get_at::<rustc_query_system[cca60478b9b5cf0a]::query::caches::DefaultCache<rustc_middle[2fef699d51b04cde]::ty::ParamEnvAnd<rustc_middle[2fef699d51b04cde]::mir::interpret::GlobalId>, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 24usize]>>>
  36:     0x7f3261a0ed19 - <rustc_middle[2fef699d51b04cde]::ty::context::TyCtxt>::const_eval_global_id_for_typeck
  37:     0x7f3261a0e4d4 - <rustc_middle[2fef699d51b04cde]::ty::context::TyCtxt>::const_eval_resolve_for_typeck
  38:     0x7f325ff8c889 - <rustc_infer[afeca00818b462f4]::infer::InferCtxt>::const_eval_resolve
  39:     0x7f3262670a2e - rustc_trait_selection[c8b9aadbf50bfac0]::traits::const_evaluatable::is_const_evaluatable.cold.0
  40:     0x7f325e095097 - <rustc_trait_selection[c8b9aadbf50bfac0]::traits::fulfill::FulfillProcessor as rustc_data_structures[40c8b2a1ba3a6075]::obligation_forest::ObligationProcessor>::process_obligation
  41:     0x7f326101bc60 - <rustc_data_structures[40c8b2a1ba3a6075]::obligation_forest::ObligationForest<rustc_trait_selection[c8b9aadbf50bfac0]::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection[c8b9aadbf50bfac0]::traits::fulfill::FulfillProcessor>
  42:     0x7f3261b20d45 - <rustc_hir_typeck[aabe17c5e1176325]::fn_ctxt::FnCtxt>::check_argument_types
  43:     0x7f32619757c7 - <rustc_hir_typeck[aabe17c5e1176325]::fn_ctxt::FnCtxt>::check_call
  44:     0x7f3261a604e3 - <rustc_hir_typeck[aabe17c5e1176325]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  45:     0x7f32615e3e5b - <rustc_hir_typeck[aabe17c5e1176325]::fn_ctxt::FnCtxt>::check_block_with_expected
  46:     0x7f3261a609c6 - <rustc_hir_typeck[aabe17c5e1176325]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  47:     0x7f3261913288 - rustc_hir_typeck[aabe17c5e1176325]::check::check_fn
  48:     0x7f32611385f1 - rustc_hir_typeck[aabe17c5e1176325]::typeck
  49:     0x7f326113789f - rustc_query_impl[2d7a486b3b483e50]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d7a486b3b483e50]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 8usize]>>
  50:     0x7f32612bf7f0 - rustc_query_system[cca60478b9b5cf0a]::query::plumbing::try_execute_query::<rustc_query_impl[2d7a486b3b483e50]::DynamicConfig<rustc_query_system[cca60478b9b5cf0a]::query::caches::VecCache<rustc_span[dca1c35612e9799e]::def_id::LocalDefId, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[2d7a486b3b483e50]::plumbing::QueryCtxt, false>
  51:     0x7f32612bf30c - rustc_query_impl[2d7a486b3b483e50]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  52:     0x7f32619cd512 - <rustc_middle[2fef699d51b04cde]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[f9243b092bfd4bc4]::check_crate::{closure#6}>::{closure#0}
  53:     0x7f32619cbddd - rustc_hir_analysis[f9243b092bfd4bc4]::check_crate
  54:     0x7f3261c0f1af - rustc_interface[3211d57ef7b44dc5]::passes::analysis
  55:     0x7f3261c0ee19 - rustc_query_impl[2d7a486b3b483e50]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[2d7a486b3b483e50]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 1usize]>>
  56:     0x7f3261d2b5a5 - rustc_query_system[cca60478b9b5cf0a]::query::plumbing::try_execute_query::<rustc_query_impl[2d7a486b3b483e50]::DynamicConfig<rustc_query_system[cca60478b9b5cf0a]::query::caches::SingleCache<rustc_middle[2fef699d51b04cde]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[2d7a486b3b483e50]::plumbing::QueryCtxt, false>
  57:     0x7f3261d2b309 - rustc_query_impl[2d7a486b3b483e50]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  58:     0x7f3261d3a7d6 - rustc_interface[3211d57ef7b44dc5]::interface::run_compiler::<core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>, rustc_driver_impl[221cda1307b92b70]::run_compiler::{closure#0}>::{closure#0}
  59:     0x7f3261fccec5 - std[1167999404bd111b]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[3211d57ef7b44dc5]::util::run_in_thread_with_globals<rustc_interface[3211d57ef7b44dc5]::util::run_in_thread_pool_with_globals<rustc_interface[3211d57ef7b44dc5]::interface::run_compiler<core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>, rustc_driver_impl[221cda1307b92b70]::run_compiler::{closure#0}>::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>
  60:     0x7f3261fcccf2 - <<std[1167999404bd111b]::thread::Builder>::spawn_unchecked_<rustc_interface[3211d57ef7b44dc5]::util::run_in_thread_with_globals<rustc_interface[3211d57ef7b44dc5]::util::run_in_thread_pool_with_globals<rustc_interface[3211d57ef7b44dc5]::interface::run_compiler<core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>, rustc_driver_impl[221cda1307b92b70]::run_compiler::{closure#0}>::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2d5c3c55c032a2b6]::result::Result<(), rustc_span[dca1c35612e9799e]::ErrorGuaranteed>>::{closure#1} as core[2d5c3c55c032a2b6]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  61:     0x7f325cd99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha029642ca6390740
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/alloc/src/boxed.rs:2016:9
  62:     0x7f325cd99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hf1943d8b8c84814b
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/alloc/src/boxed.rs:2016:9
  63:     0x7f325cd99725 - std::sys::pal::unix::thread::Thread::new::thread_start::h01e9562ca32060df
                               at /rustc/2ae1bb671183a072b54ed8ed39abfcd72990a3e7/library/std/src/sys/pal/unix/thread.rs:108:17
  64:     0x7f325cb8055a - <unknown>
  65:     0x7f325cbfda3c - <unknown>
  66:                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: rustc 1.78.0-nightly (2ae1bb671 2024-02-24) 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.VPrjJPuc2PMX/rustc_testrunner_tmpdir_reporting.xXOE8jUXEYZD/mvce.rs:6:1: 6:66>::{constant#0}`
#1 [eval_to_valtree] evaluating type-level constant
#2 [typeck] type-checking `use_trait_impl`
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0601`.

[matthiaskrgr]

#120847 cc @oli-obk