1 files changed, 5 insertions, 0 deletions
diff --git a/src/test/ui/type-inference/sort_by_key.rs b/src/test/ui/type-inference/sort_by_key.rs
new file mode 100644
index 000000000..afc4d90b8
--- /dev/null
+++ b/src/test/ui/type-inference/sort_by_key.rs
@@ -0,0 +1,5 @@
+fn main() {
+    let mut lst: [([i32; 10], bool); 10] = [([0; 10], false); 10];
+    lst.sort_by_key(|&(v, _)| v.iter().sum()); //~ ERROR type annotations needed
+    println!("{:?}", lst);
+}