SSA Refactor: Implement array cloning

[jfecher]

Problem

In Noir, arrays are cloned when moved into another variable:

let mut a = [1, 2, 3];
let b = a;

a[0] = 5;
assert(a[0] == 5);
assert(b[0] == 1);

However the SSA refactor currently does not clone them, instead arrays function more as references:

let mut a = [1, 2, 3];
let b = a;

a[0] = 5;
// Assuming this was compiled with the new ssa refactor this would hold currently
assert(a[0] == 5);
assert(b[0] == 5);

Proposed solution

Add a check when creating new variables to clone arrays.

Alternatives considered

Alternatively, change arrays to have some immutable representation that does not need to be cloned manually. An example representation would be im::Vector which would also allow us to grow these arrays.

Additional context

No response

Submission Checklist

• Once I hit submit, I will assign this issue to the Project Board with the appropriate tags.

[Savio-Sou]

@jfecher is this still relevant?

[jfecher]

Alternatively, change arrays to have some immutable representation that does not need to be cloned manually. An example representation would be im::Vector which would also allow us to grow these arrays.

This is done now, we use im::Vector for all arrays in SSA.