diff --git a/src/json.c b/src/json.c
index f4a03e6..c1c6e85 100644
--- a/src/json.c
+++ b/src/json.c
@@ -351,6 +351,7 @@
 	    break;
 #endif
 	case VAR_UNKNOWN:
+	case VAR_ANY:
 	case VAR_VOID:
 	    internal_error_no_abort("json_encode_item()");
 	    return FAIL;