ICE: `did not expect inference variables here`

[matthiaskrgr]

auto-reduced (treereduce-rust):

use std::mem;

pub trait HardcodedPayload {
    type ArrayType: AsRef<[u8]> + AsMut<[u8]> + Default + PartialEq;
    const PAYLOAD: Self::ArrayType;

    fn test() {
        let mut buf = [0u8; mem::size_of::<Self::ArrayType>()];

        if buf == Self::PAYLOAD {}
    }
}

original:

#![allow(incomplete_features)]
#![feature(const_generics, const_evaluatable_checked)]

use std::mem;

pub trait HardcodedPayload {
    type ArrayType: AsRef<[u8]> + AsMut<[u8]> + Default + PartialEq;
    const PAYLOAD: Self::ArrayType;

    fn test() where [u8; mem::size_of::<Self::ArrayType>()]: Sized + PartialEq { //workaround for `[u8; N]`
        let mut buf = [0u8; mem::size_of::<Self::ArrayType>()];
        //*insert read here*
        if buf == Self::PAYLOAD {} //crashed here
    }
}

pub struct UserStruct {
    _a: i32,
}

impl HardcodedPayload for UserStruct {
    type ArrayType = [u8; 2];
    const PAYLOAD: Self::ArrayType = [0xff, 0xff];
}

fn main() {}

Version information

rustc 1.84.0-nightly (583b25d8d 2024-11-12)
binary: rustc
commit-hash: 583b25d8d1bf934f593d9d9811f88305888032b5
commit-date: 2024-11-12
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Possibly related line of code:

rust/compiler/rustc_middle/src/mir/interpret/queries.rs

Lines 99 to 111 in 583b25d

	// variables. We reject those here since `resolve`
	// would fail otherwise.
	//
	// When trying to evaluate constants containing inference variables,
	// use `Infcx::const_eval_resolve` instead.
	if ct.args.has_non_region_infer() {
	bug!("did not expect inference variables here");
	}
	match ty::Instance::try_resolve(self, param_env, ct.def, ct.args) {
	Ok(Some(instance)) => {
	let cid = GlobalId { instance, promoted: None };
	self.const_eval_global_id_for_typeck(param_env, cid, span).inspect(|_| {

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.Rm5p7wMtuTgP/rustc_testrunner_tmpdir_reporting.KnRv1MI2yL1X/mvce.rs:12:2
   |
12 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.Rm5p7wMtuTgP/rustc_testrunner_tmpdir_reporting.KnRv1MI2yL1X/mvce.rs`

error: constant expression depends on a generic parameter
 --> /tmp/icemaker_global_tempdir.Rm5p7wMtuTgP/rustc_testrunner_tmpdir_reporting.KnRv1MI2yL1X/mvce.rs:8:29
  |
8 |         let mut buf = [0u8; mem::size_of::<Self::ArrayType>()];
  |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: this may fail depending on what value the parameter takes

error: constant expression depends on a generic parameter
  --> /tmp/icemaker_global_tempdir.Rm5p7wMtuTgP/rustc_testrunner_tmpdir_reporting.KnRv1MI2yL1X/mvce.rs:10:16
   |
10 |         if buf == Self::PAYLOAD {}
   |                ^^
   |
   = note: this may fail depending on what value the parameter takes

error: internal compiler error: compiler/rustc_middle/src/mir/interpret/queries.rs:105:13: did not expect inference variables here

thread 'rustc' panicked at compiler/rustc_middle/src/mir/interpret/queries.rs:105:13:
Box<dyn Any>
stack backtrace:
   0:     0x772aabc3edfa - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h1be162dc2503466c
   1:     0x772aac404126 - core::fmt::write::h280382204c276f4c
   2:     0x772aad8d34d1 - std::io::Write::write_fmt::h04f2b42af7342ff5
   3:     0x772aabc3ec52 - std::sys::backtrace::BacktraceLock::print::h7c048bae86e9ad26
   4:     0x772aabc41156 - std::panicking::default_hook::{{closure}}::hc244b26161cd3277
   5:     0x772aabc40fa0 - std::panicking::default_hook::h24f5ce4ffd208338
   6:     0x772aaacd1271 - std[d1ae3bd9e9976c39]::panicking::update_hook::<alloc[4c76250b199c2804]::boxed::Box<rustc_driver_impl[a2c21c8cc38ba0fe]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x772aabc41868 - std::panicking::rust_panic_with_hook::he0ab4d877fd6a339
   8:     0x772aaad0af71 - std[d1ae3bd9e9976c39]::panicking::begin_panic::<rustc_errors[e1f0737afb2aef5d]::ExplicitBug>::{closure#0}
   9:     0x772aaacfdf46 - std[d1ae3bd9e9976c39]::sys::backtrace::__rust_end_short_backtrace::<std[d1ae3bd9e9976c39]::panicking::begin_panic<rustc_errors[e1f0737afb2aef5d]::ExplicitBug>::{closure#0}, !>
  10:     0x772aaacfdf0d - std[d1ae3bd9e9976c39]::panicking::begin_panic::<rustc_errors[e1f0737afb2aef5d]::ExplicitBug>
  11:     0x772aaad14c91 - <rustc_errors[e1f0737afb2aef5d]::diagnostic::BugAbort as rustc_errors[e1f0737afb2aef5d]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x772aab391e03 - rustc_middle[805d92c067a49ea3]::util::bug::opt_span_bug_fmt::<rustc_span[1918eb9e81a65bcc]::span_encoding::Span>::{closure#0}
  13:     0x772aab3786da - rustc_middle[805d92c067a49ea3]::ty::context::tls::with_opt::<rustc_middle[805d92c067a49ea3]::util::bug::opt_span_bug_fmt<rustc_span[1918eb9e81a65bcc]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:     0x772aab37856b - rustc_middle[805d92c067a49ea3]::ty::context::tls::with_context_opt::<rustc_middle[805d92c067a49ea3]::ty::context::tls::with_opt<rustc_middle[805d92c067a49ea3]::util::bug::opt_span_bug_fmt<rustc_span[1918eb9e81a65bcc]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:     0x772aa932b600 - rustc_middle[805d92c067a49ea3]::util::bug::bug_fmt
  16:     0x772aadec6703 - <rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>::const_eval_resolve_for_typeck.cold
  17:     0x772aace8f68d - rustc_trait_selection[6ddd4e54a994aae0]::traits::try_evaluate_const
  18:     0x772aacdef60d - <rustc_trait_selection[6ddd4e54a994aae0]::traits::normalize::AssocTypeNormalizer as rustc_type_ir[3fa720567fea6e5f]::fold::TypeFolder<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>>::fold_const
  19:     0x772aacdf46ec - <rustc_middle[805d92c067a49ea3]::ty::Ty as rustc_type_ir[3fa720567fea6e5f]::fold::TypeSuperFoldable<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection[6ddd4e54a994aae0]::traits::normalize::AssocTypeNormalizer>
  20:     0x772aacdf2653 - <&rustc_middle[805d92c067a49ea3]::ty::list::RawList<(), rustc_middle[805d92c067a49ea3]::ty::generic_args::GenericArg> as rustc_type_ir[3fa720567fea6e5f]::fold::TypeFoldable<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[6ddd4e54a994aae0]::traits::normalize::AssocTypeNormalizer>
  21:     0x772aad77fa89 - <rustc_trait_selection[6ddd4e54a994aae0]::traits::normalize::AssocTypeNormalizer>::fold::<rustc_type_ir[3fa720567fea6e5f]::binder::Binder<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt, rustc_type_ir[3fa720567fea6e5f]::predicate::TraitPredicate<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>>>
  22:     0x772aad77f5c4 - rustc_trait_selection[6ddd4e54a994aae0]::traits::normalize::normalize_with_depth_to::<rustc_type_ir[3fa720567fea6e5f]::binder::Binder<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt, rustc_type_ir[3fa720567fea6e5f]::predicate::TraitPredicate<rustc_middle[805d92c067a49ea3]::ty::context::TyCtxt>>>
  23:     0x772aaba89b72 - <rustc_trait_selection[6ddd4e54a994aae0]::error_reporting::TypeErrCtxt>::try_to_add_help_message
  24:     0x772aaba7867f - <rustc_trait_selection[6ddd4e54a994aae0]::error_reporting::TypeErrCtxt>::report_selection_error
  25:     0x772aabaf3448 - <rustc_trait_selection[6ddd4e54a994aae0]::error_reporting::TypeErrCtxt>::report_fulfillment_error
  26:     0x772aabac14fd - <rustc_trait_selection[6ddd4e54a994aae0]::error_reporting::TypeErrCtxt>::report_fulfillment_errors
  27:     0x772aacdebf51 - <rustc_hir_typeck[a15215e6f6be142b]::fn_ctxt::FnCtxt>::type_inference_fallback
  28:     0x772aac617282 - rustc_hir_typeck[a15215e6f6be142b]::typeck
  29:     0x772aac616c13 - rustc_query_impl[108f2a4105e551cb]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[108f2a4105e551cb]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[805d92c067a49ea3]::query::erase::Erased<[u8; 8usize]>>
  30:     0x772aaca70401 - rustc_query_system[2e0a7198de1e86af]::query::plumbing::try_execute_query::<rustc_query_impl[108f2a4105e551cb]::DynamicConfig<rustc_query_system[2e0a7198de1e86af]::query::caches::VecCache<rustc_span[1918eb9e81a65bcc]::def_id::LocalDefId, rustc_middle[805d92c067a49ea3]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[108f2a4105e551cb]::plumbing::QueryCtxt, false>
  31:     0x772aaca6eacd - rustc_query_impl[108f2a4105e551cb]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  32:     0x772aaca6e747 - <rustc_middle[805d92c067a49ea3]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[c524f426caea01c1]::check_crate::{closure#4}>::{closure#0}
  33:     0x772aaca6c719 - rustc_hir_analysis[c524f426caea01c1]::check_crate
  34:     0x772aaca5cfca - rustc_interface[a611b3338a51bb01]::passes::run_required_analyses
  35:     0x772aad2647de - rustc_interface[a611b3338a51bb01]::passes::analysis
  36:     0x772aad2647af - rustc_query_impl[108f2a4105e551cb]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[108f2a4105e551cb]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[805d92c067a49ea3]::query::erase::Erased<[u8; 1usize]>>
  37:     0x772aad3e47ae - rustc_query_system[2e0a7198de1e86af]::query::plumbing::try_execute_query::<rustc_query_impl[108f2a4105e551cb]::DynamicConfig<rustc_query_system[2e0a7198de1e86af]::query::caches::SingleCache<rustc_middle[805d92c067a49ea3]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[108f2a4105e551cb]::plumbing::QueryCtxt, false>
  38:     0x772aad3e448e - rustc_query_impl[108f2a4105e551cb]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  39:     0x772aad2d9afa - rustc_interface[a611b3338a51bb01]::interface::run_compiler::<core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>, rustc_driver_impl[a2c21c8cc38ba0fe]::run_compiler::{closure#0}>::{closure#1}
  40:     0x772aad327950 - std[d1ae3bd9e9976c39]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[a611b3338a51bb01]::util::run_in_thread_with_globals<rustc_interface[a611b3338a51bb01]::util::run_in_thread_pool_with_globals<rustc_interface[a611b3338a51bb01]::interface::run_compiler<core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>, rustc_driver_impl[a2c21c8cc38ba0fe]::run_compiler::{closure#0}>::{closure#1}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>::{closure#0}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>
  41:     0x772aad327d6b - <<std[d1ae3bd9e9976c39]::thread::Builder>::spawn_unchecked_<rustc_interface[a611b3338a51bb01]::util::run_in_thread_with_globals<rustc_interface[a611b3338a51bb01]::util::run_in_thread_pool_with_globals<rustc_interface[a611b3338a51bb01]::interface::run_compiler<core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>, rustc_driver_impl[a2c21c8cc38ba0fe]::run_compiler::{closure#0}>::{closure#1}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>::{closure#0}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[47714ff89ab7fdfe]::result::Result<(), rustc_span[1918eb9e81a65bcc]::ErrorGuaranteed>>::{closure#1} as core[47714ff89ab7fdfe]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  42:     0x772aad328839 - std::sys::pal::unix::thread::Thread::new::thread_start::hde7850bcdc5229ae
  43:     0x772aaec3939d - <unknown>
  44:     0x772aaecbe49c - <unknown>
  45:                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 1.84.0-nightly (583b25d8d 2024-11-12) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `HardcodedPayload::test`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors

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

[matthiaskrgr]

#132927 cc @BoxyUwU

[matthiaskrgr]

smaller

pub trait T {
    type A;
    const P: Self::A;

    fn a() {
        [0u8; std::mem::size_of::<Self::A>()] == Self::P;
    }
}