1 files changed, 34 insertions, 0 deletions
diff --git a/tests/ui/fn/suggest-return-closure.rs b/tests/ui/fn/suggest-return-closure.rs
new file mode 100644
index 000000000..33daa1ea0
--- /dev/null
+++ b/tests/ui/fn/suggest-return-closure.rs
@@ -0,0 +1,34 @@
+fn fn_once() -> _ {
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types [E0121]
+    //~| NOTE not allowed in type signatures
+    //~| HELP replace with an appropriate return type
+    //~| SUGGESTION impl FnOnce()
+    //~| NOTE for more information on `Fn` traits and closure types
+    let x = String::new();
+    || {
+        drop(x);
+    }
+}
+
+fn fn_mut() -> _ {
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types [E0121]
+    //~| NOTE not allowed in type signatures
+    //~| HELP replace with an appropriate return type
+    //~| SUGGESTION impl FnMut(char)
+    //~| NOTE for more information on `Fn` traits and closure types
+    let x = String::new();
+    |c| {
+        x.push(c);
+    }
+}
+
+fn fun() -> _ {
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types [E0121]
+    //~| NOTE not allowed in type signatures
+    //~| HELP replace with an appropriate return type
+    //~| SUGGESTION impl Fn() -> i32
+    //~| NOTE for more information on `Fn` traits and closure types
+    || 1i32
+}
+
+fn main() {}