Fix build on Rust 1.15
diff --git a/src/attr.rs b/src/attr.rs
index 7584b70..9c969b1 100644
--- a/src/attr.rs
+++ b/src/attr.rs
@@ -550,9 +550,9 @@
             let nested = content.parse_terminated(NestedMeta::parse)?;
 
             Ok(MetaList {
-                ident,
-                paren_token,
-                nested,
+                ident: ident,
+                paren_token: paren_token,
+                nested: nested,
             })
         }
     }