1 files changed, 7 insertions, 0 deletions

diff --git a/rust/macros/tests/invalid/comma-sep.rs b/rust/macros/tests/invalid/comma-sep.rs
new file mode 100644
index 0000000..c9b6f44
--- /dev/null
+++ b/rust/macros/tests/invalid/comma-sep.rs
@@ -0,0 +1,7 @@
+use macros::hashmap;
+use std::collections::HashMap;
+
+fn main() {
+    // using only commas is invalid
+    let _hm: HashMap<_, _> = hashmap!('a', 1);
+}