diff --git a/optionalize-derive/src/util.rs b/optionalize-derive/src/util.rs
index c9c2d8b..f37cd2c 100644
--- a/optionalize-derive/src/util.rs
+++ b/optionalize-derive/src/util.rs
@@ -28,7 +28,7 @@ pub(crate) fn struct_fields_info<'a>(
         .map(|field| {
             let inner_ty = get_generic_ty("Option", &field.ty);
             let attr = helper_attr(&field.attrs, helper);
-            let ty = &field.ty;
+            let underlying_ty = inner_ty.unwrap_or(&field.ty);
 
             FieldInfo {
                 ident: field.ident.as_ref(),
@@ -41,10 +41,10 @@ pub(crate) fn struct_fields_info<'a>(
                                 panic!("usage of `opt` attribute is incorrect (unknown key is present)");
                             }
                             path
-                        }).unwrap_or(syn::Ident::new(&format!("{}Opt", quote::quote!(#ty)), field.span()).into())
+                        }).unwrap_or(syn::Ident::new(&format!("{}Opt", quote::quote!(#underlying_ty)), field.span()).into())
                     }),
                 is_option: inner_ty.is_some(),
-                underlying_ty: inner_ty.unwrap_or(&field.ty),
+                underlying_ty,
             }
         })
         .collect()