Field literal bounds

[aleasims]

We agreed on the following bounds on field types literals:

If p is the order of corresponding field, then literal values from

• [0; p) - use as it is,
• (-p; 0) - transform into equivalent field element from (0; p) (essentially x -> x + p),
• (-∞; -p] ∪ [p; +∞) - compilation error.

[aleasims]

However #[allow(overflowing_literals)] ignores these rules and allows to create field literals up to 48 bytes.

E.g. this:

#[allow(overflowing_literals)]
let x: __zkllvm_field_pallas_base = 0x40000000000000000000000000000000224698FC094CF91B992D30ED00000002g;

is equivalent to this:

let x: __zkllvm_field_pallas_base = 0x1g;

If you are trying to create a field literal larger than 48 bytes, you will get a compilation error anyway.