diff --git a/bip-???-cat.mediawiki b/bip-???-cat.mediawiki
index 281fa3c5..05f16d65 100644
--- a/bip-???-cat.mediawiki
+++ b/bip-???-cat.mediawiki
@@ -45,8 +45,9 @@ Implementation
 <pre>
 case OP_CAT:
 {
-    if (stack.size() < 2)
+    if (stack.size() < 2) {
         return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
+    }
     valtype& vch1 = stacktop(-2);
     valtype& vch2 = stacktop(-1);
     if (vch1.size() + vch2.size() > MAX_SCRIPT_ELEMENT_SIZE)