node.h: Avoid a magic number to represent excessed comma

`(ID)1` was assigned to NODE_ARGS#rest_arg for `{|x,| }`.
This change removes the magic number by introducing an explicit macro
variable for it: NODE_SPECIAL_EXCESSED_COMMA.

1 files changed, 1 insertions, 0 deletions

diff --git a/node.h b/node.h
index 57a0ea3932..539c3724a9 100644
--- a/node.h
+++ b/node.h
@@ -383,6 +383,7 @@ typedef struct RNode {
 #define NODE_REQUIRED_KEYWORD_P(node) ((node)->nd_value == NODE_SPECIAL_REQUIRED_KEYWORD)
 #define NODE_SPECIAL_NO_NAME_REST     ((NODE *)-1)
 #define NODE_NAMED_REST_P(node) ((node) != NODE_SPECIAL_NO_NAME_REST)
+#define NODE_SPECIAL_EXCESSED_COMMA   ((ID)1)
 
 VALUE rb_node_case_when_optimizable_literal(const NODE *const node);