1 files changed, 32 insertions, 0 deletions
diff --git a/src/test/ui/specialization/issue-52050.rs b/src/test/ui/specialization/issue-52050.rs
new file mode 100644
index 000000000..804658702
--- /dev/null
+++ b/src/test/ui/specialization/issue-52050.rs
@@ -0,0 +1,32 @@
+#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
+
+// Regression test for #52050: when inserting the blanket impl `I`
+// into the tree, we had to replace the child node for `Foo`, which
+// led to the structure of the tree being messed up.
+
+use std::iter::Iterator;
+
+trait IntoPyDictPointer { }
+
+struct Foo { }
+
+impl Iterator for Foo {
+    type Item = ();
+    fn next(&mut self) -> Option<()> {
+        None
+    }
+}
+
+impl IntoPyDictPointer for Foo { }
+
+impl<I> IntoPyDictPointer for I
+where
+    I: Iterator,
+{
+}
+
+impl IntoPyDictPointer for () //~ ERROR conflicting implementations
+{
+}
+
+fn main() { }