Add compile-time assertions on generic arguments of stdlib functions

[michaeljklein]

Problem

Several requirements on generic arguments of stdlib functions are only documented and not checked when they could be checked at compile-time.

E.g. for to_le_bits on Field:

    /// # Safety
    /// Values of `N` equal to or greater than the number of bits necessary to represent the `Field` modulus
    /// (e.g. 254 for the BN254 field) allow for multiple bit decompositions. This is due to how the `Field` will
    /// wrap around due to overflow when verifying the decomposition.
    #[builtin(to_le_bits)]
    // docs:start:to_le_bits
    pub fn to_le_bits<let N: u32>(self: Self) -> [u1; N] {}

Happy Case

1. Find such stdlib functions
2. Add compile-time assertions, e.g.

    #[builtin(to_le_bits_unsafe)]
    fn to_le_bits_unsafe<let N: u32>(self: Self) -> [u1; N] {}

    pub fn to_le_bits<let N: u32>(self: Self) -> [u1; N] {
        static_assert(N < Field_modulus, "Values of `N` equal to or greater than..");
        self.to_le_bits_unsafe::<N>()
    }

Workaround

Yes

Workaround Description

Explicitly check inputs as per stdlib function docs

Additional Context

No response

Project Impact

Nice-to-have

Blocker Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response