merge revision(s) 6bcc4664bdaebbf9b28a762ae63f476a1ec6cfb2,bb40c5cbe977de9f36a2a739e94e9b2fd4496b6e,c060bdc2b4ab8eeef5374f4174f5de48ab936d74: [Backport #17541]

	Return new NODE_LIT

	As NODE_ZLIST/NODE_LIST are not markable, cannot be reused as
	NODE_LIT.
	---
	 parse.y | 7 ++-----
	 1 file changed, 2 insertions(+), 5 deletions(-)

	Ensure symbol list node is either NODE_STR or NODE_DSTR

	---
	 parse.y | 11 ++++++++---
	 1 file changed, 8 insertions(+), 3 deletions(-)

	NODE markability should not change by nd_set_type

	---
	 node.c | 31 +++++++++++++++++++++++++------
	 node.h | 12 ++++++++++++
	 2 files changed, 37 insertions(+), 6 deletions(-)

1 files changed, 12 insertions, 0 deletions

diff --git a/node.h b/node.h
index d9dfaa5c2d..192e121fd7 100644
--- a/node.h
+++ b/node.h
@@ -187,6 +187,8 @@ typedef struct RNode {
 
 #define nd_type(n) ((int) (((n)->flags & NODE_TYPEMASK)>>NODE_TYPESHIFT))
 #define nd_set_type(n,t) \
+    rb_node_set_type(n, t)
+#define nd_init_type(n,t) \
     (n)->flags=(((n)->flags&~NODE_TYPEMASK)|((((unsigned long)(t))<<NODE_TYPESHIFT)&NODE_TYPEMASK))
 
 #define NODE_LSHIFT (NODE_TYPESHIFT+7)
@@ -471,9 +473,19 @@ void *rb_parser_realloc(struct parser_params *, void *, size_t);
 void *rb_parser_calloc(struct parser_params *, size_t, size_t);
 void rb_parser_free(struct parser_params *, void *);
 PRINTF_ARGS(void rb_parser_printf(struct parser_params *parser, const char *fmt, ...), 2, 3);
+void rb_ast_node_type_change(NODE *n, enum node_type type);
 
 RUBY_SYMBOL_EXPORT_END
 
+static inline VALUE
+rb_node_set_type(NODE *n, enum node_type t)
+{
+#if RUBY_DEBUG
+    rb_ast_node_type_change(n, t);
+#endif
+    return nd_init_type(n, t);
+}
+
 #if defined(__cplusplus)
 #if 0
 { /* satisfy cc-mode */