ICE with const_evaluatable_checked: unable to compare const generics array

[Frago9876543210]

Code

#![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() {}

Meta

rustc --version --verbose:

rustc 1.50.0-nightly (1c389ffef 2020-11-24)
binary: rustc
commit-hash: 1c389ffeff814726dec325f0f2b0c99107df2673
commit-date: 2020-11-24
host: x86_64-unknown-linux-gnu
release: 1.50.0-nightly

Error output

error: internal compiler error: compiler/rustc_traits/src/normalize_erasing_regions.rs:37:32: could not fully normalize `Const { ty: fn() -> usize {std::mem::size_of::<<Self as HardcodedPayload>::ArrayType>}, val: Value(Scalar(<ZST>)) }`

thread 'rustc' panicked at 'Box<Any>', compiler/rustc_errors/src/lib.rs:958:9

Backtrace

error: internal compiler error: compiler/rustc_traits/src/normalize_erasing_regions.rs:37:32: could not fully normalize `Const { ty: fn() -> usize {std::mem::size_of::<<Self as HardcodedPayload>::ArrayType>}, val: Value(Scalar(<ZST>)) }`

thread 'rustc' panicked at 'Box<Any>', compiler/rustc_errors/src/lib.rs:958:9
stack backtrace:
   0: std::panicking::begin_panic
   1: rustc_errors::HandlerInner::bug
   2: rustc_errors::Handler::bug
   3: rustc_middle::util::bug::opt_span_bug_fmt::{{closure}}
   4: rustc_middle::ty::context::tls::with_opt::{{closure}}
   5: rustc_middle::ty::context::tls::with_opt
   6: rustc_middle::util::bug::opt_span_bug_fmt
   7: rustc_middle::util::bug::bug_fmt
   8: rustc_infer::infer::InferCtxtBuilder::enter
   9: rustc_traits::normalize_erasing_regions::normalize_generic_arg_after_erasing_regions
  10: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  11: rustc_data_structures::stack::ensure_sufficient_stack
  12: rustc_query_system::query::plumbing::get_query_impl
  13: <rustc_middle::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_middle::ty::fold::TypeFolder>::fold_const
  14: rustc_middle::ty::normalize_erasing_regions::<impl rustc_middle::ty::context::TyCtxt>::subst_and_normalize_erasing_regions
  15: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_operand
  16: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::run
  17: rustc_mir::const_eval::eval_queries::eval_to_allocation_raw_provider
  18: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::eval_to_allocation_raw>::compute
  19: rustc_middle::ty::query::plumbing::<impl rustc_query_system::query::QueryContext for rustc_middle::ty::context::TyCtxt>::start_query::{{closure}}::{{closure}}::{{closure}}
  20: rustc_query_system::query::plumbing::get_query_impl
  21: rustc_mir::const_eval::eval_queries::eval_to_const_value_raw_provider
  22: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::eval_to_const_value_raw>::compute
  23: rustc_middle::ty::query::plumbing::<impl rustc_query_system::query::QueryContext for rustc_middle::ty::context::TyCtxt>::start_query::{{closure}}::{{closure}}::{{closure}}
  24: rustc_query_system::query::plumbing::get_query_impl
  25: rustc_mir::const_eval::eval_queries::eval_to_const_value_raw_provider
  26: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::eval_to_const_value_raw>::compute
  27: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  28: rustc_data_structures::stack::ensure_sufficient_stack
  29: rustc_query_system::query::plumbing::get_query_impl
  30: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_global_id
  31: rustc_middle::ty::consts::Const::try_eval_usize
  32: rustc_middle::ty::error::<impl rustc_middle::ty::TyS>::sort_string
  33: <rustc_middle::ty::error::TypeError as core::fmt::Display>::fmt
  34: core::fmt::write
             at /rustc/1c389ffeff814726dec325f0f2b0c99107df2673/library/core/src/fmt/mod.rs:1078:17
  35: rustc_infer::infer::error_reporting::<impl rustc_infer::infer::InferCtxt>::note_type_err
  36: rustc_infer::infer::error_reporting::<impl rustc_infer::infer::InferCtxt>::report_and_explain_type_error
  37: rustc_infer::infer::InferCtxt::report_mismatched_types
  38: rustc_typeck::check::demand::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::demand_coerce_diag
  39: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_coercable_to_type
  40: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_overloaded_binop
  41: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_binop
  42: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  43: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  44: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  45: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  46: rustc_typeck::check::_match::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_match
  47: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  48: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  49: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  50: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  51: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  52: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  53: rustc_typeck::check::check::check_fn
  54: rustc_infer::infer::InferCtxtBuilder::enter
  55: rustc_typeck::check::typeck
  56: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::typeck>::compute
  57: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  58: rustc_data_structures::stack::ensure_sufficient_stack
  59: rustc_query_system::query::plumbing::get_query_impl
  60: rustc_query_system::query::plumbing::ensure_query_impl
  61: rustc_typeck::check::typeck_item_bodies
  62: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::typeck_item_bodies>::compute
  63: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  64: rustc_data_structures::stack::ensure_sufficient_stack
  65: rustc_query_system::query::plumbing::get_query_impl
  66: rustc_typeck::check_crate
  67: rustc_interface::passes::analysis
  68: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::analysis>::compute
  69: rustc_query_system::dep_graph::graph::DepGraph<K>::with_eval_always_task
  70: rustc_data_structures::stack::ensure_sufficient_stack
  71: rustc_query_system::query::plumbing::get_query_impl
  72: rustc_interface::passes::QueryContext::enter
  73: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  74: rustc_span::with_source_map
  75: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: the compiler unexpectedly panicked. this is a bug.

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 1.50.0-nightly (1c389ffef 2020-11-24) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [normalize_generic_arg_after_erasing_regions] normalizing `std::mem::size_of::<<Self as HardcodedPayload>::ArrayType>`
#1 [eval_to_allocation_raw] const-evaluating + checking `HardcodedPayload::test::{constant#0}`
#2 [eval_to_const_value_raw] simplifying constant for the type system `HardcodedPayload::test::{constant#0}`
#3 [eval_to_const_value_raw] simplifying constant for the type system `HardcodedPayload::test::{constant#0}`
#4 [typeck] type-checking `HardcodedPayload::test`
#5 [typeck_item_bodies] type-checking all item bodies
#6 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

[BoxyUwU]

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