gleam-lang/gleam · error

bit array segment size to be a valid u32

Error message

bit array segment size to be a valid u32

What it means

Error "bit array segment size to be a valid u32" thrown in gleam-lang/gleam.

Source

Thrown at compiler-core/src/javascript.rs:1641

///
pub(crate) const SAFE_INT_SEGMENT_MAX_SIZE: usize = 48;

/// Evaluates the value of an Int segment in a bit array into its corresponding bytes. This avoids
/// needing to do the evaluation at runtime when all inputs are known at compile-time.
///
pub(crate) fn bit_array_segment_int_value_to_bytes(
    mut value: BigInt,
    size: BigInt,
    endianness: Endianness,
) -> Vec<u8> {
    // Clamp negative sizes to zero
    let size = size.max(BigInt::ZERO);

    // Convert size to u32. This is safe because this function isn't called with a size greater
    // than `SAFE_INT_SEGMENT_MAX_SIZE`.
    let size = size
        .to_u32()
        .expect("bit array segment size to be a valid u32");

    // Convert negative number to two's complement representation
    if value < BigInt::ZERO {
        let value_modulus = BigInt::from(2).pow(size);
        value = &value_modulus + (value % &value_modulus);
    }

    // Convert value to the desired number of bytes
    let mut bytes = vec![0u8; size as usize / 8];
    for byte in bytes.iter_mut() {
        *byte = (&value % BigInt::from(256))
            .to_u8()
            .expect("modulo result to be a valid u32");
        value /= BigInt::from(256);
    }

    if endianness.is_big() {
        bytes.reverse();

View on GitHub (pinned to 7e623aa83d)

When it happens

Trigger: Thrown at compiler-core/src/javascript.rs:1641 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of gleam-lang/gleam@7e623aa83d (2026-08-17). Data as JSON: /api/errors/7a610342e0a674fc. Report an issue: GitHub.