diff --git a/serde_dhall/src/value.rs b/serde_dhall/src/value.rs
index df81a850..2fef7e9b 100644
--- a/serde_dhall/src/value.rs
+++ b/serde_dhall/src/value.rs
@@ -475,12 +475,7 @@ impl SimpleType {
             NirKind::UnionType(kts) => SimpleType::Union(
                 kts.iter()
                     .map(|(k, v)| {
-                        Some((
-                            k.into(),
-                            v.as_ref()
-                                .map(|v| Ok(Self::from_nir(v)?))
-                                .transpose()?,
-                        ))
+                        Some((k.into(), v.as_ref().and_then(Self::from_nir)))
                     })
                     .collect::<Option<_>>()?,
             ),