1 files changed, 13 insertions, 0 deletions
diff --git a/tests/ui/borrowck/index-mut-help.rs b/tests/ui/borrowck/index-mut-help.rs
new file mode 100644
index 000000000..35266e113
--- /dev/null
+++ b/tests/ui/borrowck/index-mut-help.rs
@@ -0,0 +1,13 @@
+// When mutably indexing a type that implements `Index` but not `IndexMut`, a
+// special 'help' message is added to the output.
+use std::collections::HashMap;
+
+
+fn main() {
+    let mut map = HashMap::new();
+    map.insert("peter", "23".to_string());
+
+    map["peter"].clear();           //~ ERROR
+    map["peter"] = "0".to_string(); //~ ERROR
+    let _ = &mut map["peter"];      //~ ERROR
+}