1 files changed, 62 insertions, 0 deletions
diff --git a/src/test/ui/associated-types/issue-67684.rs b/src/test/ui/associated-types/issue-67684.rs
new file mode 100644
index 000000000..49efe8a1b
--- /dev/null
+++ b/src/test/ui/associated-types/issue-67684.rs
@@ -0,0 +1,62 @@
+// check-pass
+
+#![allow(dead_code)]
+
+trait ParseError {
+    type StreamError;
+}
+
+impl<T> ParseError for T {
+    type StreamError = ();
+}
+
+trait Stream {
+    type Item;
+    type Error: ParseError;
+}
+
+trait Parser
+where
+    <Self as Parser>::PartialState: Default,
+{
+    type PartialState;
+    fn parse_mode(_: &Self, _: Self::PartialState) {
+        loop {}
+    }
+}
+
+impl Stream for () {
+    type Item = ();
+    type Error = ();
+}
+
+impl Parser for () {
+    type PartialState = ();
+}
+
+struct AndThen<A, B>(core::marker::PhantomData<(A, B)>);
+
+impl<A, B> Parser for AndThen<A, B>
+where
+    A: Stream,
+    B: Into<<A::Error as ParseError>::StreamError>,
+{
+    type PartialState = ();
+}
+
+fn expr<A>() -> impl Parser
+where
+    A: Stream<Error = <A as Stream>::Item>,
+{
+    AndThen::<A, ()>(core::marker::PhantomData)
+}
+
+fn parse_mode_impl<A>()
+where
+    <A as Stream>::Error: ParseError,
+    A: Stream<Error = <A as Stream>::Item>,
+{
+    Parser::parse_mode(&expr::<A>(), Default::default())
+}
+
+fn main() {}