use struct in serialize impl

card_game/src/lib.rs

@@ -716,8 +716,18 @@ where
 			}
 		}
 
-		use serde::ser::SerializeStruct;
+		#[derive(serde_derive::Serialize)]
-		let mut map = serializer.serialize_struct("Session", 3)?;
+		#[serde(bound(serialize = "
+			G: serde::Serialize,
+			SessionConfig<G::Config>: serde::Serialize,
+			G::Instruction: serde::Serialize,
+		"))]
+		struct SerializedSession<'a, G: Game> {
+			config: &'a SessionConfig<G::Config>,
+			state: &'a G,
+			history: History<'a, G>,
+		}
+
 		// serialize the initial state of the game.
 		// if there is history, it is the first snapshot's state,
 		// otherwise it is the current game state since there are no moves.
@@ -726,9 +736,11 @@ where
 		} else {
 			&self.state.state
 		};
-		map.serialize_field("config", &self.config)?;
+		let session = SerializedSession {
-		map.serialize_field("state", state)?;
+			config: &self.config,
-		map.serialize_field("history", &History(&self.state.history))?;
+			state,
-		map.end()
+			history: History(&self.state.history),
+		};
+		session.serialize(serializer)
 	}
 }