Merge torrust#2: Introduce failing test for flattened enums

43ba81e Introduce failing test for flattened enums (Nicholas Rempel)

Pull request description:

  From: #31 (comment)
  By: [nrempel](https://github.com/nrempel)

  ```
  Hello,

  This pull request adds a failing test for deserializing flattened structs containing enums.

  Is it expected that this test should pass or is there some serde caveat that I'm unaware of here? I'm happy to take a crack at fixing this if it's fixable. Any pointers would be appreciated.

  Thanks.
  ```

ACKs for top commit:
  josecelano:
    ACK 43ba81e

Tree-SHA512: aa996152a2a7a583b7a6eff54b99edfb0872ebf77803cab376e9db19200cbacd42bef11fc51a33254fd13d6eb5f67f483e23a90bf008f2fe1ade4aa55118453e

tests/tests.rs

@@ -444,3 +444,35 @@ fn ser_de_field_vec_tuple() {
 
     test_ser_de_eq(foo);
 }
+
+#[test]
+fn ser_de_flattened_enum() {
+    #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
+    struct KrpcMessage {
+        message_type: MessageType,
+    }
+
+    #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
+    enum MessageType {
+        Query,
+        Response,
+    }
+
+    #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
+    struct KrpcResponse {
+        #[serde(flatten)]
+        krpc: KrpcMessage,
+    }
+
+    // Passes
+    test_ser_de_eq(KrpcMessage {
+        message_type: MessageType::Response,
+    });
+
+    // Fails
+    test_ser_de_eq(KrpcResponse {
+        krpc: KrpcMessage {
+            message_type: MessageType::Response,
+        },
+    });
+}