Constant POINT_BOUND_UNSUPPORTED 

pub const POINT_BOUND_UNSUPPORTED: &str = "a curve path piece bounded by a point on a curve this evaluator does not invert (an \
     intrinsic curve, a chain, an elevated or banked curve, an offset, or a family other than a \
     line, a circle, an ellipse, a polyline or a B-spline): state its parameter instead";

The input a point bound on a curve this evaluator does not invert is refused for.