Couldn't evaluate constant const with -Zpolymorphize=on

[Naserume]

Code

#![crate_type = "lib"]

pub fn demo_for_i32() {
    generic_impl::<bool>();
}

fn generic_impl<T>() {
    trait MagicTrait {
        const IS_BIG: bool;
    }
    impl<T> MagicTrait for T {
        const IS_BIG: bool = std::mem::size_of::<T>() > 10;
    }
    if T::IS_BIG {
        big_impl::<i32>();
    }  
}

fn big_impl<T>() {}

to run : rustc ./218ADF953E15EE53.rs -Zpolymorphize=on

Meta

rustc --version --verbose:

binary: rustc
commit-hash: f9b16149208c8a8a349c32813312716f6603eb6f
commit-date: 2024-04-19
host: x86_64-apple-darwin
release: 1.79.0-nightly
LLVM version: 18.1.4

Backtrace

error: internal compiler error: compiler/rustc_middle/src/mir/mod.rs:705:17: Couldn't evaluate constant const ::IS_BIG in mono Instance { def: Item(DefId(0:4 ~ 218ADF953E15EE53629956193E34723D019B7FF6E6049185C3303B99BE33D7C5[f8df]::generic_impl)), args: [T/#0] }

thread 'rustc' panicked at compiler/rustc_middle/src/mir/mod.rs:705:17:
Box
stack backtrace:
0: 0x10f0ac063 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h339f4af9bea4aeb1
1: 0x10f0f796b - core::fmt::write::h5a043ff03a3bd9b7
2: 0x10f0a212e - std::io::Write::write_fmt::hc9f26722443714d2
3: 0x10f0abe51 - std::sys_common::backtrace::print::hec15b0a1b187f43a
4: 0x10f0aeb49 - std::panicking::default_hook::{{closure}}::h77f4382f34966180
5: 0x10f0ae890 - std::panicking::default_hook::h95d46dff794c86a6
6: 0x117d26b3c - std[96c9014e9cc79c42]::panicking::update_hook::<alloc[b139a52cb69f6f02]::boxed::Box<rustc_driver_impl[aed2792d0255fb8]::install_ice_hook::{closure#0}>>::{closure#0}
7: 0x10f0af643 - std::panicking::rust_panic_with_hook::h19343a55bc932df0
8: 0x117d8e3ba - std[96c9014e9cc79c42]::panicking::begin_panic::<rustc_errors[2542ce93eb2c5131]::ExplicitBug>::{closure#0}
9: 0x117d87619 - std[96c9014e9cc79c42]::sys_common::backtrace::__rust_end_short_backtrace::<std[96c9014e9cc79c42]::panicking::begin_panic<rustc_errors[2542ce93eb2c5131]::ExplicitBug>::{closure#0}, !>
10: 0x11c4d34c9 - std[96c9014e9cc79c42]::panicking::begin_panic::<rustc_errors[2542ce93eb2c5131]::ExplicitBug>
11: 0x117da1c66 - <rustc_errors[2542ce93eb2c5131]::diagnostic::BugAbort as rustc_errors[2542ce93eb2c5131]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
12: 0x11888728e - rustc_middle[8b834d5ab41b7c4a]::util::bug::opt_span_bug_fmt::<rustc_span[3aebbb9d197be42]::span_encoding::Span>::{closure#0}
13: 0x118838177 - rustc_middle[8b834d5ab41b7c4a]::ty::context::tls::with_opt::<rustc_middle[8b834d5ab41b7c4a]::util::bug::opt_span_bug_fmt<rustc_span[3aebbb9d197be42]::span_encoding::Span>::{closure#0}, !>::{closure#0}
14: 0x118837be5 - rustc_middle[8b834d5ab41b7c4a]::ty::context::tls::with_context_opt::<rustc_middle[8b834d5ab41b7c4a]::ty::context::tls::with_opt<rustc_middle[8b834d5ab41b7c4a]::util::bug::opt_span_bug_fmt<rustc_span[3aebbb9d197be42]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
15: 0x11c59300b - rustc_middle[8b834d5ab41b7c4a]::util::bug::bug_fmt
16: 0x1187f371e - <rustc_middle[8b834d5ab41b7c4a]::mir::Body>::try_const_mono_switchint::{closure#0}
17: 0x1187f1584 - <rustc_middle[8b834d5ab41b7c4a]::mir::traversal::MonoReachable as core[48b09eea7890b3ea]::iter::traits::iterator::Iterator>::next
18: 0x118c4007c - rustc_monomorphize[d079dae585a9066d]::collector::collect_items_rec::{closure#0}
19: 0x118c3e2e7 - rustc_monomorphize[d079dae585a9066d]::collector::collect_items_rec
20: 0x118c3f917 - rustc_monomorphize[d079dae585a9066d]::collector::collect_items_rec
21: 0x118c34c7d - rustc_monomorphize[d079dae585a9066d]::partitioning::collect_and_partition_mono_items
22: 0x1191898d6 - rustc_query_impl[ab5369b0d00fe824]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ab5369b0d00fe824]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8b834d5ab41b7c4a]::query::erase::Erased<[u8; 24usize]>>
23: 0x1191545fe - <rustc_query_impl[ab5369b0d00fe824]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[48b09eea7890b3ea]::ops::function::FnOnce<(rustc_middle[8b834d5ab41b7c4a]::ty::context::TyCtxt, ())>>::call_once
24: 0x118f700bd - rustc_query_system[aa282dbe93ac58a4]::query::plumbing::try_execute_query::<rustc_query_impl[ab5369b0d00fe824]::DynamicConfig<rustc_query_system[aa282dbe93ac58a4]::query::caches::SingleCache<rustc_middle[8b834d5ab41b7c4a]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[ab5369b0d00fe824]::plumbing::QueryCtxt, false>
25: 0x1191de5b3 - rustc_query_impl[ab5369b0d00fe824]::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace
26: 0x117b768a0 - rustc_codegen_ssa[b745cd5c81484d7f]::back::symbol_export::exported_symbols_provider_local
27: 0x119186b43 - rustc_query_impl[ab5369b0d00fe824]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ab5369b0d00fe824]::query_impl::exported_symbols::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8b834d5ab41b7c4a]::query::erase::Erased<[u8; 16usize]>>
28: 0x119128e6e - <rustc_query_impl[ab5369b0d00fe824]::query_impl::exported_symbols::dynamic_query::{closure#2} as core[48b09eea7890b3ea]::ops::function::FnOnce<(rustc_middle[8b834d5ab41b7c4a]::ty::context::TyCtxt, rustc_span[3aebbb9d197be42]::def_id::CrateNum)>>::call_once
29: 0x119010105 - rustc_query_system[aa282dbe93ac58a4]::query::plumbing::try_execute_query::<rustc_query_impl[ab5369b0d00fe824]::DynamicConfig<rustc_query_system[aa282dbe93ac58a4]::query::caches::VecCache<rustc_span[3aebbb9d197be42]::def_id::LocalDefId, rustc_middle[8b834d5ab41b7c4a]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[ab5369b0d00fe824]::plumbing::QueryCtxt, false>
30: 0x1191de1b1 - rustc_query_impl[ab5369b0d00fe824]::query_impl::exported_symbols::get_query_non_incr::__rust_end_short_backtrace
31: 0x118609feb - rustc_middle[8b834d5ab41b7c4a]::query::plumbing::query_get_at::<rustc_query_system[aa282dbe93ac58a4]::query::caches::VecCache<rustc_span[3aebbb9d197be42]::def_id::CrateNum, rustc_middle[8b834d5ab41b7c4a]::query::erase::Erased<[u8; 16usize]>>>
32: 0x11869f227 - <rustc_metadata[4282c498f3a5aba6]::rmeta::encoder::EncodeContext>::encode_crate_root
33: 0x1186b3ae8 - rustc_metadata[4282c498f3a5aba6]::rmeta::encoder::encode_metadata
34: 0x1186c7b3f - rustc_metadata[4282c498f3a5aba6]::fs::encode_and_write_metadata
35: 0x1184f35a5 - rustc_interface[5475460b5e821a32]::passes::start_codegen
36: 0x1184fb99a - <rustc_interface[5475460b5e821a32]::queries::Queries>::codegen_and_build_linker
37: 0x117d2540e - rustc_interface[5475460b5e821a32]::interface::run_compiler::<core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>, rustc_driver_impl[aed2792d0255fb8]::run_compiler::{closure#0}>::{closure#1}
38: 0x117d1c7f1 - std[96c9014e9cc79c42]::sys_common::backtrace::_rust_begin_short_backtrace::<rustc_interface[5475460b5e821a32]::util::run_in_thread_with_globals<rustc_interface[5475460b5e821a32]::util::run_in_thread_pool_with_globals<rustc_interface[5475460b5e821a32]::interface::run_compiler<core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>, rustc_driver_impl[aed2792d0255fb8]::run_compiler::{closure#0}>::{closure#1}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>::{closure#0}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>
39: 0x117d2ea96 - <<std[96c9014e9cc79c42]::thread::Builder>::spawn_unchecked<rustc_interface[5475460b5e821a32]::util::run_in_thread_with_globals<rustc_interface[5475460b5e821a32]::util::run_in_thread_pool_with_globals<rustc_interface[5475460b5e821a32]::interface::run_compiler<core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>, rustc_driver_impl[aed2792d0255fb8]::run_compiler::{closure#0}>::{closure#1}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>::{closure#0}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[48b09eea7890b3ea]::result::Result<(), rustc_span[3aebbb9d197be42]::ErrorGuaranteed>>::{closure#2} as core[48b09eea7890b3ea]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
40: 0x10f0b8d0b - std::sys::pal::unix::thread::Thread::new::thread_start::h41e33ca082edcdc5
41: 0x7ff818270202 - __pthread_start

note: compiler flags: -Z polymorphize=on

query stack during panic:
#0 [collect_and_partition_mono_items] collect_and_partition_mono_items
#1 [exported_symbols] collecting exported symbols for crate 0
end of query stack
error: aborting due to 1 previous error

[matthiaskrgr]

duplicate of #123893 , even the exact same code lol

[Naserume]

Omg you're right