1 files changed, 26 insertions, 0 deletions
diff --git a/tests/ui/nll/user-annotations/issue-55241.rs b/tests/ui/nll/user-annotations/issue-55241.rs
new file mode 100644
index 000000000..29969c7b4
--- /dev/null
+++ b/tests/ui/nll/user-annotations/issue-55241.rs
@@ -0,0 +1,26 @@
+// Regression test for #55241:
+//
+// The reference to `C::HASHED_NULL_NODE` resulted in a type like `<C
+// as NodeCodec<_>>::Out`; normalizing this type requires knowing the
+// value of `_`; solving that requires having normalized, so we can
+// test against `C: NodeCodec<H>` in the environment.
+//
+// run-pass
+
+pub trait Hasher {
+    type Out: Eq;
+}
+
+pub trait NodeCodec<H: Hasher> {
+    const HASHED_NULL_NODE: H::Out;
+}
+
+pub trait Trie<H: Hasher, C: NodeCodec<H>> {
+    /// Returns the root of the trie.
+    fn root(&self) -> &H::Out;
+
+    /// Is the trie empty?
+    fn is_empty(&self) -> bool { *self.root() == C::HASHED_NULL_NODE }
+}
+
+fn main() { }