1 files changed, 21 insertions, 0 deletions
diff --git a/tests/ui/fn/fn-trait-formatting.rs b/tests/ui/fn/fn-trait-formatting.rs
new file mode 100644
index 000000000..636ac7107
--- /dev/null
+++ b/tests/ui/fn/fn-trait-formatting.rs
@@ -0,0 +1,21 @@
+fn needs_fn<F>(x: F) where F: Fn(isize) -> isize {}
+
+
+
+fn main() {
+    let _: () = Box::new(|_: isize| {}) as Box<dyn FnOnce(isize)>;
+    //~^ ERROR mismatched types
+    //~| expected unit type `()`
+    //~| found struct `Box<dyn FnOnce(isize)>`
+    let _: () = Box::new(|_: isize, isize| {}) as Box<dyn Fn(isize, isize)>;
+    //~^ ERROR mismatched types
+    //~| expected unit type `()`
+    //~| found struct `Box<dyn Fn(isize, isize)>`
+    let _: () = Box::new(|| -> isize { unimplemented!() }) as Box<dyn FnMut() -> isize>;
+    //~^ ERROR mismatched types
+    //~| expected unit type `()`
+    //~| found struct `Box<dyn FnMut() -> isize>`
+
+    needs_fn(1);
+    //~^ ERROR expected a `Fn<(isize,)>` closure, found `{integer}`
+}