diff --git a/.cargo/config.toml b/.cargo/config.toml
index 808b4c07..68c292af 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -11,6 +11,7 @@ ruma-clippy = """\
     -W clippy::dbg_macro \
     -W clippy::disallowed_type \
     -W clippy::empty_line_after_outer_attr \
+    -W clippy::exhaustive_enums \
     -W clippy::exhaustive_structs \
     -W clippy::inefficient_to_string \
     -W clippy::macro_use_imports \
diff --git a/crates/ruma-serde-macros/src/outgoing.rs b/crates/ruma-serde-macros/src/outgoing.rs
index d219323b..d344f54d 100644
--- a/crates/ruma-serde-macros/src/outgoing.rs
+++ b/crates/ruma-serde-macros/src/outgoing.rs
@@ -159,6 +159,7 @@ fn filter_input_attrs(attr: &Attribute) -> bool {
         || attr.path.is_ident("cfg_attr")
         || attr.path.is_ident("serde")
         || attr.path.is_ident("non_exhaustive")
+        || attr.path.is_ident("allow")
 }
 
 fn impl_outgoing_with_incoming_self(input: &DeriveInput, ruma_serde: &TokenStream) -> TokenStream {
diff --git a/crates/ruma/tests/outgoing.rs b/crates/ruma/tests/outgoing.rs
index 7d6fae04..b4c16983 100644
--- a/crates/ruma/tests/outgoing.rs
+++ b/crates/ruma/tests/outgoing.rs
@@ -27,6 +27,7 @@ pub struct OtherThing<'t> {
 
 #[derive(Outgoing)]
 #[incoming_derive(!Deserialize)]
+#[non_exhaustive]
 pub struct FakeRequest<'a, T> {
     pub abc: &'a str,
     pub thing: Thing<'a, T>,
@@ -44,6 +45,7 @@ pub struct FakeRequest<'a, T> {
 
 #[derive(Outgoing)]
 #[incoming_derive(!Deserialize)]
+#[non_exhaustive]
 pub enum EnumThing<'a, T> {
     Abc(&'a str),
     Stuff(Thing<'a, T>),