Function attach 

pub fn attach(
    tool: &str,
    args: &Value,
    err: SurfaceError,
    allocated: impl FnOnce(usize) -> Option<usize>,
) -> SurfaceError

Decorate an effect tool’s error with its corrected call (module docs): apply, plan and execute only; every other tool’s error passes through, and so does one that already carries a fix (the selector’s, the compile’s). allocated(i) plans the effects before i and counts their symbols (read only for a missing $new.n).