1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/async-await/return-ty-unsize-coercion.rs b/src/test/ui/async-await/return-ty-unsize-coercion.rs
new file mode 100644
index 000000000..93832ef7e
--- /dev/null
+++ b/src/test/ui/async-await/return-ty-unsize-coercion.rs
@@ -0,0 +1,45 @@
+// Check that we apply unsizing coercions based on the return type.
+//
+// Also serves as a regression test for #60424.
+//
+// edition:2018
+// check-pass
+
+#![allow(warnings)]
+
+use std::fmt::Debug;
+
+// Unsizing coercion from `Box<&'static str>` to `Box<dyn Debug>`.
+fn unsize_trait_coercion() {
+    fn sync_example() -> Box<dyn Debug> {
+        Box::new("asdf")
+    }
+
+    async fn async_example() -> Box<dyn Debug> {
+        Box::new("asdf")
+    }
+}
+
+// Unsizing coercion from `Box<[u32; N]>` to `Box<[32]>`.
+fn unsize_slice_coercion() {
+    fn sync_example() -> Box<[u32]> {
+        Box::new([0])
+    }
+
+    async fn async_example() -> Box<[u32]> {
+        Box::new([0])
+    }
+}
+
+// Unsizing coercion from `&[&str; 1]` to `&[&str]`
+fn unsize_slice_str_coercion() {
+    fn sync_example() -> &'static [&'static str] {
+        &["hi"]
+    }
+
+    async fn async_example() -> &'static [&'static str] {
+        &["hi"]
+    }
+}
+
+fn main() {}