`binius_field` overflow errors

[lcnr]

The specific breakage has been fixed by rust-lang/rust#158643. The underlying issue still persists however.

---

Followup to #257. I thought the issues in #t-types/trait-system-refactor > crater triage :3 @ 💬 had the same root cause for whatever reason, they don't.

I should not have tracked the other 2 minimizations via

There are 3 different issues here, make sure the remaining ones are also tracked.

[lcnr]

use std::ops::Add;
pub trait Field: Sized + Add<Output = Self> + WithUnderlier<Underlier: PackScalar<Self>> {}
pub trait PackScalar<F>: UnderlierType {
    type Packed;
}
pub trait PackedField: Sized + Add<Output = Self> {
    type Scalar;
}
pub trait UnderlierType: 'static {}
pub trait WithUnderlier {
    type Underlier;
}
impl<U: UnderlierType> WithUnderlier for U {
    type Underlier = U;
}
impl UnderlierType for u8 {}
pub struct MyField;
impl Field for MyField {}
impl WithUnderlier for MyField {
    type Underlier = u8;
}
impl Add<Self> for MyField {
    type Output = Self;
    fn add(self, _: Self) -> Self::Output {
        unimplemented!()
    }
}
pub struct PackedPrimitiveType<U, Scalar>(U, Scalar);
impl<U, Scalar> Add for PackedPrimitiveType<U, Scalar> {
    type Output = Self;
    fn add(self, _: Self) -> Self::Output {
        unimplemented!()
    }
}
impl<U, Scalar> PackedField for PackedPrimitiveType<U, Scalar>
where
    U: From<Scalar::Underlier>,
    Scalar: Field,
{
    type Scalar = Scalar;
}
impl<F> PackScalar<F> for u8
where
    PackedPrimitiveType<u8, F>: PackedField<Scalar = F>,
{
    type Packed = PackedPrimitiveType<u8, F>;
}
pub trait PackedTransformationFactory<OP> {}
pub trait TaggedPackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
impl<OP> PackedTransformationFactory<OP> for PackedPrimitiveType<u8, MyField>
where
    OP: PackedField,
    Self: TaggedPackedTransformationFactory<OP>,
{
}

error[E0275]: overflow evaluating the requirement `PackedPrimitiveType<u8, MyField>: PackedField`
  --> src/main.rs:53:11
   |
53 |     Self: TaggedPackedTransformationFactory<OP>,
   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: required by a bound in `TaggedPackedTransformationFactory`
  --> src/main.rs:49:50
   |
49 | pub trait TaggedPackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `TaggedPackedTransformationFactory`

[lcnr]

use std::ops::Add;
pub trait Field:
    Sized + Add<Output = Self> + WithUnderlier<Underlier: PackScalar<Self>>
{
}
pub trait PackScalar<F>: UnderlierType {
    type Packed;
}
pub trait PackedField {
    type Scalar;
}
pub trait UnderlierType: 'static {}
pub trait WithUnderlier {
    type Underlier;
}
impl<U: UnderlierType> WithUnderlier for U {
    type Underlier = U;
}
impl UnderlierType for u8 {}
pub struct MyField;
impl Field for MyField {}
impl WithUnderlier for MyField {
    type Underlier = u8;
}
impl Add<Self> for MyField {
    type Output = Self;
    fn add(self, _: Self) -> Self::Output {
        unimplemented!()
    }
}
pub struct PackedPrimitiveType<U, Scalar: Field>(U, Scalar);
impl<U, Scalar> PackedField for PackedPrimitiveType<U, Scalar>
where
    U: From<Scalar::Underlier>,
    Scalar: Field,
{
    type Scalar = Scalar;
}
impl<F> PackScalar<F> for u8
where
    F: Field,
{
    type Packed = PackedPrimitiveType<u8, F>;
}
pub trait PackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
pub trait TaggedPackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
impl<OP> PackedTransformationFactory<OP> for PackedPrimitiveType<u8, MyField> where
    Self: TaggedPackedTransformationFactory<OP>
{
}

error[E0275]: overflow evaluating the requirement `<<PackedPrimitiveType<u8, MyField> as PackedField>::Scalar as WithUnderlier>::Underlier: PackScalar<<PackedPrimitiveType<u8, ...> as PackedField>::Scalar>`
  --> src/main.rs:47:10
   |
47 | impl<OP> PackedTransformationFactory<OP> for PackedPrimitiveType<u8, MyField> where
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: required for `<PackedPrimitiveType<u8, MyField> as PackedField>::Scalar` to implement `Field`
  --> src/main.rs:2:11
   |
 2 | pub trait Field:
   |           ^^^^^
note: required by a bound in `PackedTransformationFactory`
  --> src/main.rs:45:64
   |
45 | pub trait PackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
   |                                                                ^^^^^ required by this bound in `PackedTransformationFactory`

error[E0275]: overflow evaluating the requirement `PackedPrimitiveType<u8, MyField>: PackedField`
  --> src/main.rs:47:46
   |
47 | impl<OP> PackedTransformationFactory<OP> for PackedPrimitiveType<u8, MyField> where
   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: required by a bound in `PackedTransformationFactory`
  --> src/main.rs:45:44
   |
45 | pub trait PackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
   |                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `PackedTransformationFactory`

error[E0275]: overflow evaluating the requirement `PackedPrimitiveType<u8, MyField>: PackedField`
  --> src/main.rs:48:11
   |
48 |     Self: TaggedPackedTransformationFactory<OP>
   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: required by a bound in `TaggedPackedTransformationFactory`
  --> src/main.rs:46:50
   |
46 | pub trait TaggedPackedTransformationFactory<OP>: PackedField<Scalar: Field> {}
   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `TaggedPackedTransformationFactory`

error[E0275]: overflow evaluating whether `PackedPrimitiveType<u8, MyField>` is well-formed
  --> src/main.rs:47:46
   |
47 | impl<OP> PackedTransformationFactory<OP> for PackedPrimitiveType<u8, MyField> where
   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0275]: overflow evaluating whether `PackedPrimitiveType<u8, MyField>` is well-formed
  --> src/main.rs:48:11
   |
48 |     Self: TaggedPackedTransformationFactory<OP>
   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[lcnr]

this is the same problem as one of the issues in ml-kem #246 (comment) and e.g. fixed by rust-lang/rust#148069

[lcnr]

resolved this concrete issue by treating ParamEnv candidates as rigid rust-lang/rust#158643. The underlying isuse is not fixed