1 files changed, 7 insertions, 0 deletions
diff --git a/tests/ui/type/issue-58355.rs b/tests/ui/type/issue-58355.rs
new file mode 100644
index 000000000..3b62fdece
--- /dev/null
+++ b/tests/ui/type/issue-58355.rs
@@ -0,0 +1,7 @@
+#![crate_type = "lib"]
+
+pub fn foo(callback: fn() -> dyn ToString) {
+    let mut x: Option<Box<dyn Fn() -> dyn ToString>> = None;
+    x = Some(Box::new(callback));
+    //~^ ERROR: the size for values of type `dyn ToString` cannot be known at compilation time
+}