diff --git a/src/expr.rs b/src/expr.rs
index a847733e7bd..d276bcc2951 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -1615,7 +1615,9 @@ fn rewrite_match_arms(
             arm_shape,
             &arm_indent_str,
         ));
-        result.push_str(&comment);
+        if !comment.chars().all(|c| c == ' ') {
+            result.push_str(&comment);
+        }
         result.push('\n');
         result.push_str(&arm_indent_str);