diff --git a/src/formatters/luau.rs b/src/formatters/luau.rs
index 21a74ac9..b0189630 100644
--- a/src/formatters/luau.rs
+++ b/src/formatters/luau.rs
@@ -43,6 +43,7 @@ pub fn format_compound_op(ctx: &Context, compound_op: &CompoundOp, shape: Shape)
         PercentEqual = " %= ",
         CaretEqual = " ^= ",
         TwoDotsEqual = " ..= ",
+        DoubleSlashEqual = " //= ",
     }, |other| panic!("unknown node {:?}", other))
 }