Function validate_range_decimal 

pub fn validate_range_decimal<D>(
    field: &'static str,
    value: &D,
    min: Option<i64>,
    max: Option<i64>,
) -> Result<(), CratestackError>
where
    D: DecimalValue,

Decimal-typed @range enforcement. The parser accepts integer bounds (@range(min: 0, max: 100)) on both Int and Decimal fields; the i64 bounds are promoted to Decimal here so monetary fields can declare the same shape as integer counters. Banks routinely write things like amount Decimal @range(min: 0) to forbid negative amounts at the framework layer — without this, the validator silently no-ops and out-of-range values reach the database.

Generic over DecimalValue (cratestack#505 Direction 2) rather than the crate’s single Decimal alias, so this function is unconditional — no #[cfg] gate, no dependency on either backend feature — and works identically for RustDecimal, BigDecimal, or any other type satisfying the bound. Generated code calls this with value already typed as the field’s own concrete decimal type, so D is inferred at the call site; no turbofish needed.