Add a test for the problem with the serde feature

Author: fjarri

tests/weird.rs

@@ -0,0 +1,38 @@
+use core::fmt::{Debug};
+
+use serde_::{Serialize, Deserialize};
+
+pub trait Protocol<Id> {
+    type ProtocolError: ProtocolError<Id>;
+}
+
+pub trait ProtocolError<Id>: Debug + Clone + Serialize + for<'de> Deserialize<'de> {}
+
+/// A trait defining two protocols executed sequentially.
+pub trait ChainedProtocol<Id>: 'static + Debug {
+    type Protocol1: Protocol<Id>;
+}
+
+/// The protocol error type for the chained protocol.
+#[derive_where::derive_where(Debug, Clone)]
+#[derive(Serialize, Deserialize)]
+#[serde(crate = "serde_")]
+#[serde(bound(serialize = "
+    <C::Protocol1 as Protocol<Id>>::ProtocolError: Serialize,
+"))]
+#[serde(bound(deserialize = "
+    <C::Protocol1 as Protocol<Id>>::ProtocolError: for<'x> Deserialize<'x>,
+"))]
+pub enum ChainedProtocolError<Id, C>
+where
+    C: ChainedProtocol<Id>,
+{
+    Protocol1(<C::Protocol1 as Protocol<Id>>::ProtocolError),
+}
+
+impl<Id, C> ProtocolError<Id> for ChainedProtocolError<Id, C>
+where
+    C: ChainedProtocol<Id>,
+{
+
+}