Check correctness of as_u32 method in mem.rs

[kevaundray]

Problem

We currently use as_u32 to coerce a field element into a u32 by taking its value modulo 2^32.

See:

noir/crates/noirc_evaluator/src/ssa/mem.rs

Line 97 in b8c582f

pub fn as_u32(value: FieldElement) -> u32 {

Solution

We should document whether this is safe to do, and or whether we should actually be enforcing that its value is reduced beforehand.

Alternatives considered

Additional context