size handling: Make OutlineOccultable return type Copy

It is.  Declare it, so we can reuse it nicely.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/src/shapelib.rs b/src/shapelib.rs
index 0521bbca56e70d3ec6890ff7bfca2cc040684696..4bedf3c38054688a546d881bdbc3937b06d85f33 100644 (file)
--- a/src/shapelib.rs
+++ b/src/shapelib.rs
@@ -221,7 +221,7 @@ impl<T> SvgBaseName<T> where T: Borrow<GoodItemName> {
 }
 
 impl OutlineCalculable {
-  pub fn err_mapper(&self) -> impl Fn(LLE) -> IE {
+  pub fn err_mapper(&self) -> impl Fn(LLE) -> IE + Copy {
     |e| internal_logic_error(format!(
       "outline calculable but failed {} {:?}",&e,&e
     ))