Function boolean_with_conformity 

pub fn boolean_with_conformity(
    a: &[Tri],
    b: &[Tri],
    op: BoolOp,
) -> (Vec<Tri>, bool)

Like boolean, but also returns whether the underlying pairwise arrangement was CONFORMING (Arrangement::unrecovered == 0) — the same (result, conforming) shape union_all already returns for the N-ary union. boolean() computes this exact arrangement and discards the signal on purpose (its graceful degrade when unrecovered > 0 is intentional; see its doc comment, and contrast difference_all’s hard reject). This function changes no behaviour — it is an observation-only companion for callers (tests, diagnostics) that want to inspect the signal boolean() throws away, without altering boolean()’s own return type or any existing caller.