When I run `cargo test`, I get an `unexpected panic` error.

[reud]

I'm a first time Rust user, so I think this code is not good. I apologize for that.

While trying to implement an elliptic curve cryptography library in Rust, I tried to run the code for testing once with cargo test and got an internal compiler error: and was advised to share the bug report, so here I am sharing it.

Code

use std::fmt::{Display, Formatter};
use std::fmt;
use std::ops::{Sub, Add, Mul, Rem, Div};
use num_traits::{NumOps, Num, One, Zero};

// Debugの自動実装
#[derive(Debug, Copy, Clone)]
pub struct FieldElement {
    pub num: u64,
    pub prime: u64
}

// P.5 練習問題1
impl PartialEq for FieldElement {
    fn eq(&self, other: &Self) -> bool {
        return self.num == other.num && self.prime == other.prime;
    }
}

impl Add for FieldElement {
    type Output = FieldElement;

    // 左側のprimeに依存させる。
    fn add(self, rhs: FieldElement) -> FieldElement {
        Self::Output{
            prime: self.prime,
            num: (self.num+rhs.num).rem_euclid(self.prime)
        }
    }
}

impl Sub for FieldElement {
    type Output = FieldElement;

    fn sub(self, rhs: FieldElement) -> FieldElement {
        Self::Output{
            prime: self.prime,
            num: ((self.num as i128) - (rhs.num as i128)).rem_euclid(self.prime as i128) as u64
        }
    }
}

impl Mul for FieldElement {
    type Output = FieldElement;

    fn mul(self, rhs: FieldElement) -> FieldElement {
        Self::Output{
            prime: self.prime,
            num: ((self.num as i128) * (rhs.num as i128)).rem_euclid(self.prime as i128) as u64
        }
    }
}

impl Rem for FieldElement {
    type Output = FieldElement;

    fn rem(self, rhs: FieldElement) -> FieldElement {
        Self::Output{
            prime: self.prime,
            num: ((self.num as i128) % (rhs.num as i128)).rem_euclid(self.prime as i128) as u64
        }
    }
}


// TODO: どうにかして実装したい。
impl FieldElement {
    fn inner_pow(self,f: FieldElement,exp: u64) -> FieldElement {
        if exp == 0 {
            return FieldElement{
                num: 1,
                prime: f.prime
            }
        }
        if exp % 2 == 0 {
            return self.inner_pow(FieldElement{
                num: (f.num * f.num).rem_euclid(f.prime),
                prime: f.prime,
            },exp / 2);
        }
        f * f.inner_pow(FieldElement{
            num: (f.num * f.num).rem_euclid(f.prime),
            prime: f.prime,
        },(exp-1)/2)
    }
    // rem_euclidを使って負数でもよしなに整数値に変更する。
    pub fn pow(self, exp: i64) -> FieldElement {
        self.inner_pow(self, exp.rem_euclid((self.prime - 1) as i64) as u64)
    }

    // フェルマーの小定理からインバースを実装する。 位数が素数で無い場合は正しく動作しない
    pub fn inv(self) -> FieldElement {
        return self.pow((self.prime - 2) as i64)
    }
}

impl Div for FieldElement {
    type Output = FieldElement;

    fn div(self, rhs: Self) -> Self::Output {
        return self * rhs.inv();
    }
}

impl Display for FieldElement {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f,"{}",self.num)
    }
}

pub fn new_field_element(num: i64, prime: u64) -> FieldElement {
    FieldElement{
        num: num.rem_euclid(prime as i64) as u64,
        prime
    }
}

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

    #[test]
    fn test_field_element_all() {
        {
            let a = new_field_element(7,13);
            let b = new_field_element(6,13);

            println!("{}",a == b);
            println!("{}",a != b);

            println!("{}",a == a);
            println!("{}",a != a);
        }

        // P.9 練習問題2
        {
            println!("P.9 Q2");
            {
                let a = new_field_element(44,57);
                let b = new_field_element(33,57);
                println!("{}",a + b);
            }
            {
                let a = new_field_element(9,57);
                let b = new_field_element(-29,57);
                println!("{}", a + b);
            }
            {
                let a = new_field_element(17,57);
                let b = new_field_element(42,57);
                let c = new_field_element(49,57);
                println!("{}", a + b + c);
            }
            {
                let a = new_field_element(52,57);
                let b = new_field_element(-30,57);
                let c = new_field_element(-38,57);
                println!("{}", a + b + c);
            }
        }

        // P.10 練習問題3
        {
            println!("P.10 Q3");
            {
                let a = new_field_element(44,57);
                let b = new_field_element(33,57);
                println!("{}",a - b);
            }
            {
                let a = new_field_element(9,57);
                let b = new_field_element(-29,57);
                println!("{}", a - b);
            }
            {
                let a = new_field_element(17,57);
                let b = new_field_element(42,57);
                let c = new_field_element(49,57);
                println!("{}", a + b - c);
            }
            {
                let a = new_field_element(52,57);
                let b = new_field_element(-30,57);
                let c = new_field_element(-38,57);
                println!("{}", a + b - c);
            }
        }

        // P.11 練習問題4
        {
            println!("P.11 Q4");
            {
                let a = new_field_element(95,97);
                let b = new_field_element(45,97);
                let c = new_field_element(31,97);
                println!("{}",a * b * c);
            }
            {
                let a = new_field_element(17,97);
                let b = new_field_element(13,97);
                let c = new_field_element(19,97);
                let d = new_field_element(44,97);
                println!("{}", a * b * c * d);
            }
            {
                let a = new_field_element(12,97).pow(7);
                let b = new_field_element(77,97).pow(49);
                println!("{}", a * b);
            }
        }

        // P.11 練習問題5
        {
            println!("P.11 Q5");
            let solver = |k: i32|{
                print!("k = {{");
                for i in 0..19 {
                    let f = new_field_element((i * k) as i64, 19);
                    print!(" {},",f)
                }
                print!("}} \n");
            };
            solver(1);
            solver(3);
            solver(7);
            solver(17);
            solver(18);
        }

        // P.12 練習問題6
        {
            println!("P.12 Q6");
            let f = new_field_element((7 * 7),31);
            println!("F31 7 * 7 = {}",f)
        }

        // P.13 練習問題7
        {
            println!("P.13 Q7");
            let solver = |k: i32|{
                print!("k = {} {{",k);
                for i in 0..k-1 {
                    let f = new_field_element((i + 1) as i64, k as u64);
                    print!(" {},",f.pow((k - 1) as i64))
                }
                print!("}} \n");
            };

            solver(7);
            solver(11);
            solver(17);
            solver(31);
        }

        // P.16 練習問題8
        {
            println!("P.16 練習問題");
            {
                let l = new_field_element(3,31);
                let r = new_field_element(24,31);
                println!("F31 3/24 = {}",l/r);
            }
            {
                let l = new_field_element(17,31);
                println!("F31 17^(-3) = {}",l.pow(-3));
            }
            {
                let l = new_field_element(4,31);
                println!("F31 4^(-4) * 11 = {}",l.pow(-4) * new_field_element(11,31));
            }
        }

        // P.16 練習問題9
        {
            {
                let l = new_field_element(3,31);
                let r = new_field_element(24,31);
                println!("F31 3/24 = {}",l/r);
            }
        }
    }
}

Meta

rustc --version --verbose:

rustc 1.53.0-nightly (bb491ed23 2021-04-23)
binary: rustc
commit-hash: bb491ed23937aef876622e4beb68ae95938b3bf9
commit-date: 2021-04-23
host: x86_64-unknown-linux-gnu
release: 1.53.0-nightly
LLVM version: 12.0.0

Error output

thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(8556428269209080887, 4269101851060977991))`,
 right: `Some(Fingerprint(14469595183014616750, 10866501170494209091))`: found unstable fingerprints for predicates_of(core[ec89]::cmp::PartialEq): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::cmp::PartialEq<Rhs>>), []), /home/reud/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/cmp.rs:202:1: 202:40 (#0))] }', /rustc/bb491ed23937aef876622e4beb68ae95938b3bf9/compiler/rustc_query_system/src/query/plumbing.rs:593:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

error: internal compiler error: unexpected panic

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 1.53.0-nightly (bb491ed23 2021-04-23) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::cmp::PartialEq`
#1 [typeck] type-checking `ecc::field_element::tests::test_field_element_all`
end of query stack
warning: 5 warnings emitted

error: could not compile `pg-bitcoin`

To learn more, run the command again with --verbose.

Backtrace

thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(8556428269209080887, 4269101851060977991))`,
 right: `Some(Fingerprint(14469595183014616750, 10866501170494209091))`: found unstable fingerprints for predicates_of(core[ec89]::cmp::PartialEq): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::cmp::PartialEq<Rhs>>), []), /home/reud/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/cmp.rs:202:1: 202:40 (#0))] }', /rustc/bb491ed23937aef876622e4beb68ae95938b3bf9/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/bb491ed23937aef876622e4beb68ae95938b3bf9/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/bb491ed23937aef876622e4beb68ae95938b3bf9/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_middle::ty::generics::GenericPredicates::instantiate_into
   9: rustc_middle::ty::generics::GenericPredicates::instantiate
  10: rustc_typeck::check::method::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::lookup_method_in_trait
  11: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::lookup_op_method
  12: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_overloaded_binop
  13: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_binop
  14: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  15: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  16: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  17: <smallvec::SmallVec<A> as core::iter::traits::collect::Extend<<A as smallvec::Array>::Item>>::extend
  18: <T as rustc_middle::ty::context::InternIteratorElement<T,R>>::intern_with
  19: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  20: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  21: rustc_typeck::check::_match::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::demand_scrutinee_type
  22: rustc_typeck::check::_match::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_match
  23: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  24: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  25: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  26: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  27: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_argument_types
  28: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::confirm_builtin_call
  29: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_call
  30: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  31: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  32: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_argument_types
  33: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::confirm_builtin_call
  34: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_call
  35: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  36: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  37: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_stmt
  38: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  39: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  40: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_stmt
  41: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  42: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  43: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_stmt
  44: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  45: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  46: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  47: rustc_typeck::check::check::check_fn
  48: rustc_infer::infer::InferCtxtBuilder::enter
  49: rustc_typeck::check::typeck
  50: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  51: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  52: rustc_data_structures::stack::ensure_sufficient_stack
  53: rustc_query_system::query::plumbing::force_query_with_job
  54: rustc_query_system::query::plumbing::get_query_impl
  55: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  56: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  57: rustc_typeck::check::typeck_item_bodies
  58: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  59: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  60: rustc_data_structures::stack::ensure_sufficient_stack
  61: rustc_query_system::query::plumbing::force_query_with_job
  62: rustc_query_system::query::plumbing::get_query_impl
  63: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck_item_bodies
  64: rustc_session::utils::<impl rustc_session::session::Session>::time
  65: rustc_typeck::check_crate
  66: rustc_interface::passes::analysis
  67: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  68: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  69: rustc_data_structures::stack::ensure_sufficient_stack
  70: rustc_query_system::query::plumbing::force_query_with_job
  71: rustc_query_system::query::plumbing::get_query_impl
  72: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  73: rustc_interface::passes::QueryContext::enter
  74: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  75: rustc_span::with_source_map
  76: rustc_interface::interface::create_compiler_and_run
  77: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

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 1.53.0-nightly (bb491ed23 2021-04-23) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::cmp::PartialEq`
#1 [typeck] type-checking `ecc::field_element::tests::test_field_element_all`
#2 [typeck_item_bodies] type-checking all item bodies
#3 [analysis] running analysis passes on this crate
end of query stack
warning: 5 warnings emitted

error: could not compile `pg-bitcoin`

To learn more, run the command again with --verbose.

[JohnTitor]

Should be related to #84341, as a workaround, cargo clean or disabling incr-comp would fix the ICE.

[Aaron1011]

Duplicate of #84341. This is fixed in the latest nightly