Dynamic indices for non-homogenous array

[vezenovm]

Problem

Reference this unimplemented macro in ACIR gen (

noir/crates/noirc_evaluator/src/ssa/acir_gen/mod.rs

Line 575 in 93726c4

"Non-const array indices is not implemented for non-homogenous array"

).

With the introduction of dynamic indices for slices as well in this PR (#2446) enabling dynamic indices for arrays of complex types is necessary to avoid inconsistencies in our array/slice implementations.

Happy Case

Non-const indices should be fully supported just like const indices for both arrays and slices.

Alternatives Considered

N/A, there is no reasonable alternative

Additional Context

No response

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[Savio-Sou]

What does "non-homogenous array" here mean?

Aren't arrays in Noir strictly required to be homogeneous, as in all elements in a Noir array must be of the same type?

(Or is this referring to Rust arrays in ACIR?)

[vezenovm]

"Non-homogenous array" means an array of structs basically, technically if we had a struct like such:

struct Bar {
    inner: [Field; 3],
}
struct Foo {
    a: Field,
    b: [Field; 3],
    bar: Bar,
}

and an array x : [Foo; 4] the array is homogenous for the Foo type. But we flatten structs into its internal type structure so it is in fact an array with the types Field, [Field; 3], [Field; 3], thus being non-homogenous.