Function custom_shape_value 

pub fn custom_shape_value(shape: &CustomShape) -> Shape

The shape as one of the crate’s super::Shape values.

.fill(_:) and .fill_style(…) work: they reach _ShapeView through its descriptor and four key arguments, so no name is involved. The methods that compose a result name — .inset, .rotation, .stroked and the rest — cannot: they build a mangled name for the result type, and a type minted at run time has none that swift_getTypeByMangledName will resolve. Those fail with this shape’s name in the message rather than silently.