support boxed Iterator in Option

1 files changed, 2 insertions, 2 deletions

diff --git a/src/lib.rs b/src/lib.rs
index fc81e42..1f75023 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -390,9 +390,9 @@ impl TypeTransform {
                 let inner = opt.convert(quote!(x));
                 quote! {#arg.map(|x| #inner)}
             }
-            TypeTransform::Iterator(inner) => {
+            TypeTransform::Iterator(box_type, inner) => {
                 let inner = inner.convert(quote!(x));
-                quote! {Box::new(#arg.map(|x| #inner))}
+                quote! {Box::new(#arg.map(|x| #inner)) as #box_type}
             }
             TypeTransform::Result(ok, err) => {
                 let map_ok = !matches!(ok.as_ref(), TypeTransform::NoOp);