derive_generators doesn't properly catch non-constant starting_index before compiler panics

[leovido]

Aim

Compile with no issues

Expected Behavior

To compile without any errors

Bug

This happens when I run nargo compile

Here is the code:

fn main(age_commit: pub Field, age: u8, expected_age: pub u8, age_blinding: u32) -> pub bool {
    let age_field = [age as Field];
    let recomputed_age_commit = std::hash::pedersen_hash_with_separator(age_field, age_blinding);

    let commit_valid = (recomputed_age_commit == age_commit);

    let comparison = (age >= expected_age);

    assert(commit_valid & comparison)
    commit_valid & comparison
}

To Reproduce

1. Start a new Nargo project
2. Copy the main function
3. Run nargo compile
4. Expect error

Workaround

None

Workaround Description

No response

Additional Context

No response

Project Impact

None

Blocker Context

No response

Nargo Version

nargo version = 1.0.0-beta.1 noirc version = 1.0.0-beta.1+03b58fa2dfcc8acc8cf5198b1b23b55676fbdb02 (git version hash: 03b58fa, is dirty: false)

NoirJS Version

No response

Proving Backend Tooling & Version

0.66.0

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[TomAFrench]

Hey, this shouldn't be panicking but it's also not expected that this should compile correctly. The separator argument must be known at compile-time so we don't support programs like the above.

For your purposes I'd recommend including the blinding term as part of the hash.

Thank you for reporting this!