diff --git a/clap_derive/src/derives/args.rs b/clap_derive/src/derives/args.rs
index c801eeb9..5117a4d2 100644
--- a/clap_derive/src/derives/args.rs
+++ b/clap_derive/src/derives/args.rs
@@ -241,7 +241,7 @@ pub fn gen_augment(
                 }
             }
             Kind::Arg(ty) => {
-                let convert_type = inner_type(**ty, &field.ty);
+                let convert_type = inner_type(&field.ty);
 
                 let occurrences = *attrs.parser().kind == ParserKind::FromOccurrences;
                 let flag = *attrs.parser().kind == ParserKind::FromFlag;
@@ -524,7 +524,7 @@ fn gen_parsers(
     let parser = attrs.parser();
     let func = &parser.func;
     let span = parser.kind.span();
-    let convert_type = inner_type(**ty, &field.ty);
+    let convert_type = inner_type(&field.ty);
     let id = attrs.id();
     let (get_one, get_many, deref, mut parse) = match *parser.kind {
         FromOccurrences => (
diff --git a/clap_derive/src/utils/ty.rs b/clap_derive/src/utils/ty.rs
index 891aa37d..1bd23c76 100644
--- a/clap_derive/src/utils/ty.rs
+++ b/clap_derive/src/utils/ty.rs
@@ -40,8 +40,9 @@ impl Ty {
     }
 }
 
-pub fn inner_type(ty: Ty, field_ty: &syn::Type) -> &syn::Type {
-    match ty {
+pub fn inner_type(field_ty: &syn::Type) -> &syn::Type {
+    let ty = Ty::from_syn_ty(field_ty);
+    match *ty {
         Ty::Vec | Ty::Option => sub_type(field_ty).unwrap_or(field_ty),
         Ty::OptionOption | Ty::OptionVec => {
             sub_type(field_ty).and_then(sub_type).unwrap_or(field_ty)