diff --git a/src/http/playground_source.rs b/src/http/playground_source.rs
index a357d05f..44506e20 100644
--- a/src/http/playground_source.rs
+++ b/src/http/playground_source.rs
@@ -548,10 +548,16 @@ pub fn playground_source<T: Serialize>(config: &T) -> String {
         })
 }
 
+/// Config for GraphQL Playground
 #[derive(Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct GraphQLPlaygroundConfig {
+    /// Query endpoint
     pub endpoint: String,
+
+    /// Subscription endpoint, for example: `ws://localhost:8000`
     pub subscription_endpoint: Option<String>,
+
+    /// HTTP headers
     pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/types/connection/mod.rs b/src/types/connection/mod.rs
index d9958ff6..0bb62a25 100644
--- a/src/types/connection/mod.rs
+++ b/src/types/connection/mod.rs
@@ -248,7 +248,7 @@ pub async fn query<Cursor, Node, ConnectionFields, EdgeFields, F, R>(
     before: Option<String>,
     first: Option<i32>,
     last: Option<i32>,
-    mut f: F,
+    f: F,
 ) -> FieldResult<Connection<Cursor, Node, ConnectionFields, EdgeFields>>
 where
     Cursor: CursorType + Send + Sync,