Compiler internal error when using generic_const_exprs, and initialising struct in main

[B83C]

Code

use std::ops::BitXor;

const P32: u32 = 0xB7E15163; /* e -2 */
const Q32: u32 = 0x9E3779B9; /* Golden Ratio -1 */
const LG_W: u32 = 32_usize.ilog2();

pub struct Rc6<const ROUNDS: usize>
where
    [(); 2 * ROUNDS + 4]: Sized,
{
    key: [u32; 2 * ROUNDS + 4],
}

pub fn align(block: &[u8]) -> &[u32] {
    let (p, blocks_aligned, _) = unsafe { block.align_to() };
    assert!(p.len() == 0);
    blocks_aligned
}

impl<const ROUNDS: usize> Rc6<ROUNDS>
where
    [(); 2 * ROUNDS + 4]: Sized,
{
    pub fn new(key: &[u32]) -> Self {
        let mut S = [0u32; 2 * ROUNDS + 4];
        let mut L = Vec::from(key);
        // L[0] = key[0];
        S[0] = P32;
        let mut last_key = S[0];
        for s in &mut S[1..] {
            *s = last_key.wrapping_add(Q32);
            last_key = *s;
        }
        let mut a = 0u32;
        let mut b = 0u32;
        for s in 0..3 * L.len().max(S.len()) {
            let i = (s).wrapping_rem(S.len());
            let j = (s).wrapping_rem(L.len());
            a = (S[i].wrapping_add(a).wrapping_add(b)).rotate_left(3);
            b = (L[j].wrapping_add(a).wrapping_add(b)).rotate_left(a.wrapping_add(b));
            S[i] = a;
            L[j] = b;
        }
        Self { key: S }
    }

    pub fn encrypt(&self, block_cipher: &[u32]) -> Vec<u8> {
        let (s, [s_2r2, s_2r3]) = self
            .key
            .split_last_chunk()
            .map(|(a, b)| (a, b.clone()))
            .unwrap();
        let (cipher_blocks, _) = block_cipher.as_chunks();
        cipher_blocks
            .iter()
            .cloned()
            .map(|[mut a, mut b, mut c, mut d]| {
                b = b.wrapping_add(s[0]);
                d = d.wrapping_add(s[1]);
                let (chunks, _) = s[2..].as_chunks();
                for [s_i, s_i1] in chunks.iter().cloned() {
                    let t = Self::round(b);
                    let u = Self::round(d);
                    a = a.bitxor(t).rotate_left(u).wrapping_add(s_i);
                    c = c.bitxor(u).rotate_left(t).wrapping_add(s_i1);
                    (a, b, c, d) = (b, c, d, a);
                }
                a = a.wrapping_add(s_2r2);
                c = c.wrapping_add(s_2r3);
                [a, b, c, d].map(|u| u.to_le_bytes()).concat()
            })
            .flatten()
            .collect::<Vec<_>>()
    }

    pub fn decrypt(&self, block_cipher: &[u32]) -> Vec<u8> {
        let (s, [s_2r2, s_2r3]) = self
            .key
            .split_last_chunk()
            .map(|(a, b)| (a, b.clone()))
            .unwrap();
        let (cipher_blocks, _) = block_cipher.as_chunks();
        cipher_blocks
            .iter()
            .cloned()
            .map(|[mut a, mut b, mut c, mut d]| {
                let (chunks, _) = s[2..].as_chunks();
                a = a.wrapping_sub(s_2r2);
                c = c.wrapping_sub(s_2r3);
                for [s_i, s_i1] in chunks.iter().rev().cloned() {
                    (a, b, c, d) = (d, a, b, c);
                    let t = Self::round(b);
                    let u = Self::round(d);
                    a = a.wrapping_sub(s_i).rotate_right(u).bitxor(t);
                    c = c.wrapping_sub(s_i1).rotate_right(t).bitxor(u);
                }
                b = b.wrapping_sub(s[0]);
                d = d.wrapping_sub(s[1]);
                [a, b, c, d].map(|u| u.to_le_bytes()).concat()
            })
            .flatten()
            .collect::<Vec<_>>()
    }

    fn round(i: u32) -> u32 {
        i.wrapping_mul(i.wrapping_mul(2).wrapping_add(1))
            .rotate_left(LG_W)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn encrypt() {
        let rc6 = Rc6::<20>::new(&[0u32; 4]);
        let enc = rc6.encrypt(&[0u32; 4]);
        let res = [
            0x8f, 0xc3, 0xa5, 0x36, 0x56, 0xb1, 0xf7, 0x78, 0xc1, 0x29, 0xdf, 0x4e, 0x98, 0x48,
            0xa4, 0x1e,
        ];
        assert_eq!(enc, res);

        let key2 = vec![0x67452301, 0xefcdab89, 0x34231201, 0x78675645];
        let rc6 = Rc6::<20>::new(&key2);
        let enc2 = rc6.encrypt(align(&[
            0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf,
            0xe0, 0xf1,
        ]));
        let res2 = [
            0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23, 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4,
            0x3f, 0x18,
        ];
        assert_eq!(enc2, res2);
    }

    #[test]
    fn inverse() {
        // Encrypt and decrypt should be inverses of each other
        let cipher = [0u8; 4 * 4];
        let key = vec![0u32; 4];
        let rc6 = Rc6::<20>::new(&key);
        assert_eq!(
            cipher,
            rc6.decrypt(align(&rc6.encrypt(align(&cipher)))).as_slice()
        );

        let cipher = [
            0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf,
            0xe0, 0xf1,
        ];
        assert_eq!(
            cipher,
            rc6.decrypt(align(&rc6.encrypt(align(&cipher)))).as_slice()
        );
    }

    #[test]
    fn decrypt() {
        let key = vec![0u32; 4];
        let rc6 = Rc6::<20>::new(&key);
        let dec = rc6.decrypt(align(&[
            0x8f, 0xc3, 0xa5, 0x36, 0x56, 0xb1, 0xf7, 0x78, 0xc1, 0x29, 0xdf, 0x4e, 0x98, 0x48,
            0xa4, 0x1e,
        ]));
        let res = [
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00,
        ];
        assert_eq!(dec, res);

        let key2 = vec![0x67452301, 0xefcdab89, 0x34231201, 0x78675645];
        let rc6 = Rc6::<20>::new(&key2);
        let dec2 = rc6.decrypt(align(&[
            0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23, 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4,
            0x3f, 0x18,
        ]));
        let res2 = [
            0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf,
            0xe0, 0xf1,
        ];
        assert_eq!(dec2, res2);
    }
}

fn main() -> AppResult<()> {
    let args = Args::parse();

    let file = File::open(args.img)?;
    let mmap = unsafe { Mmap::map(&file)? };

    let header_rc6 = Rc6::<20>::new(&[0u32; 4]);
    let dec = header_rc6.decrypt(align(&mmap[0..1024]));
}

Meta

rustc --version --verbose:

rustc 1.87.0-nightly (f4a216d28 2025-03-02)
binary: rustc
commit-hash: f4a216d28ee635afce685b4206e713579f66e130
commit-date: 2025-03-02
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Error output

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> src/lib.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

note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:598:27 - disabled backtrace

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: please attach the file at `/home/b83c/r/phoenixcard-rs/rustc-ice-2025-03-03T06_25_41-363890.txt` to your bug report

note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C linker=/usr/bin/clang -C incremental=[REDACTED] -C link-arg=--ld-path=/usr/bin/mold

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack

Backtrace

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:598:27
             0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
             1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
             2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
             3: <rustc_errors::DiagCtxtHandle>::delayed_bug::<&str>
             4: rustc_trait_selection::traits::try_evaluate_const.cold
             5: <rustc_trait_selection::traits::normalize::AssocTypeNormalizer as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_const
             6: <rustc_middle::ty::Ty as rustc_type_ir::fold::TypeSuperFoldable<rustc_middle::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection::traits::normalize::AssocTypeNormalizer>
             7: <&rustc_middle::ty::list::RawList<(), rustc_middle::ty::generic_args::GenericArg> as rustc_type_ir::fold::TypeFoldable<rustc_middle::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection::traits::normalize::AssocTypeNormalizer>
             8: <rustc_middle::ty::InstantiatedPredicates as rustc_type_ir::fold::TypeFoldable<rustc_middle::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection::traits::normalize::AssocTypeNormalizer>
             9: <rustc_infer::infer::at::At as rustc_trait_selection::traits::normalize::NormalizeExt>::normalize::<rustc_middle::ty::InstantiatedPredicates>
            10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::instantiate_value_path
            11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_path
            12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_decl
            15: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
            16: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            17: rustc_hir_typeck::check::check_fn
            18: rustc_hir_typeck::typeck_with_inspect::{closure#0}
            19: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
            20: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            21: rustc_query_impl::query_impl::typeck::get_query_incr::__rust_end_short_backtrace
            22: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_hir_analysis::check_crate::{closure#3}>::{closure#0}
            23: rustc_hir_analysis::check_crate
            24: rustc_interface::passes::run_required_analyses
            25: rustc_interface::passes::analysis
            26: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
            27: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            28: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
            29: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
            30: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
            31: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
            32: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
            33: std::sys::pal::unix::thread::Thread::new::thread_start
            34: <unknown>
            35: <unknown>
          

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:598:27
             0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
             1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
             2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
             3: <rustc_errors::DiagCtxtHandle>::delayed_bug::<&str>
             4: rustc_trait_selection::traits::try_evaluate_const.cold
             5: <rustc_trait_selection::traits::normalize::AssocTypeNormalizer as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_const
             6: <rustc_middle::ty::InstantiatedPredicates as rustc_type_ir::fold::TypeFoldable<rustc_middle::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection::traits::normalize::AssocTypeNormalizer>
             7: <rustc_infer::infer::at::At as rustc_trait_selection::traits::normalize::NormalizeExt>::normalize::<rustc_middle::ty::InstantiatedPredicates>
             8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::instantiate_value_path
             9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_path
            10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_decl
            13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
            14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
            15: rustc_hir_typeck::check::check_fn
            16: rustc_hir_typeck::typeck_with_inspect::{closure#0}
            17: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
            18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            19: rustc_query_impl::query_impl::typeck::get_query_incr::__rust_end_short_backtrace
            20: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_hir_analysis::check_crate::{closure#3}>::{closure#0}
            21: rustc_hir_analysis::check_crate
            22: rustc_interface::passes::run_required_analyses
            23: rustc_interface::passes::analysis
            24: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
            25: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            26: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
            27: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
            28: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
            29: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
            30: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
            31: std::sys::pal::unix::thread::Thread::new::thread_start
            32: <unknown>
            33: <unknown>

[B83C]

cargo test works just fine when I don't initialise the struct in main (but instead in unit tests)

[cyrgani]

duplicate of #133199 maybe

[theemathas]

This is incomplete code. At the very least, it's missing some imports and missing the #![feature]. Could you provide enough code that other people could compile to reproduce the error?