Wrong SSA generated for mutable parameters of type MutableReference

[alexvitkov]

Aim

The following code should set x to 100 and the assert should pass. However, x's value remains unchanged.
This only happens if the a parameter of become_100 is declared as mutable.

fn become_100(mut a: &mut u32) {
    *a = 100;
}

fn main() {
    let mut x: u32 = 50;
    become_100(&mut x);
    assert(x == 100);
}

Expected Behavior

Assert should pass

Bug

SSA generated if the parameter is declared as mutable (incorrect):

acir fn become_100 f1 {
  b0(v0: reference):
    v1 = allocate
    store v0 at v1
    store u32 100 at v1
    return
}

SSA if the parameter is immutable (correct)

acir fn become_100 f1 {
  b0(v0: reference):
    store u32 100 at v0
    return
}

To Reproduce

Installation Method

Compiled from source

Nargo Version

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

No

Support Needs

No response