1 files changed, 19 insertions, 0 deletions

diff --git a/src/test/ui/issues/issue-78720.rs b/src/test/ui/issues/issue-78720.rs
new file mode 100644
index 00000000000..57615d1a207
--- /dev/null
+++ b/src/test/ui/issues/issue-78720.rs
@@ -0,0 +1,19 @@
+fn server() -> impl {
+//~^ ERROR at least one trait must be specified
+    ().map2(|| "")
+}
+
+trait FilterBase2 {
+    fn map2<F>(self, F) -> Map2<F> {}
+    //~^ ERROR mismatched types
+    //~^^ ERROR the size for values of type `Self` cannot be known at compilation time
+}
+
+struct Map2<Segment2> {
+    _func: F,
+    //~^ ERROR cannot find type `F` in this scope
+}
+
+impl<F> FilterBase2 for F {}
+
+fn main() {}