workaround hrtb Fn* not being (de)serializable

Author: alecmocatta

src/convenience.rs

@@ -704,6 +704,16 @@ impl<'a, Args, Output> AsRef<Self> for dyn FnOnce<Args, Output = Output> + Send
 		self
 	}
 }
+impl<'a, A, Output> AsRef<Self> for dyn for<'r> FnOnce<(&'r A,), Output = Output> + 'a {
+	fn as_ref(&self) -> &Self {
+		self
+	}
+}
+impl<'a, A, Output> AsRef<Self> for dyn for<'r> FnOnce<(&'r A,), Output = Output> + Send + 'a {
+	fn as_ref(&self) -> &Self {
+		self
+	}
+}
 
 impl<Args: 'static, Output: 'static> serde::ser::Serialize for dyn FnOnce<Args, Output = Output> {
 	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -744,6 +754,50 @@ impl<'de, Args: 'static, Output: 'static> serde::de::Deserialize<'de>
 			.map(|x| x.0)
 	}
 }
+impl<A: 'static, Output: 'static> serde::ser::Serialize
+	for dyn for<'r> FnOnce<(&'r A,), Output = Output>
+{
+	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+	where
+		S: serde::Serializer,
+	{
+		serialize(self, serializer)
+	}
+}
+impl<'de, A: 'static, Output: 'static> serde::de::Deserialize<'de>
+	for boxed::Box<dyn for<'r> FnOnce<(&'r A,), Output = Output> + 'static>
+{
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: serde::Deserializer<'de>,
+	{
+		<Box<dyn for<'r> FnOnce<(&'r A,), Output = Output> + 'static>>::deserialize(deserializer)
+			.map(|x| x.0)
+	}
+}
+impl<A: 'static, Output: 'static> serde::ser::Serialize
+	for dyn for<'r> FnOnce<(&'r A,), Output = Output> + Send
+{
+	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+	where
+		S: serde::Serializer,
+	{
+		serialize(self, serializer)
+	}
+}
+impl<'de, A: 'static, Output: 'static> serde::de::Deserialize<'de>
+	for boxed::Box<dyn for<'r> FnOnce<(&'r A,), Output = Output> + Send + 'static>
+{
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: serde::Deserializer<'de>,
+	{
+		<Box<dyn for<'r> FnOnce<(&'r A,), Output = Output> + Send + 'static>>::deserialize(
+			deserializer,
+		)
+		.map(|x| x.0)
+	}
+}
 
 /// A convenience trait implemented on all (de)serializable implementors of [`std::ops::FnMut`].
 ///

src/lib.rs

@@ -120,6 +120,9 @@
 	clippy::pedantic
 )] // from https://github.com/rust-unofficial/patterns/blob/master/anti_patterns/deny-warnings.md
 #![allow(clippy::must_use_candidate, clippy::missing_errors_doc)]
+// At some point this, and the HRTB Fn* impls, will be invalid
+// See https://github.com/rust-lang/rust/issues/56105
+#![allow(coherence_leak_check)]
 
 mod convenience;