This is also a preparation for removing not_used members from
STR NODE. Current codes work without node type check because NODE_STR
has not_used2 member corresponding to nd_next of NODE_LIST and
NODE_DSTR. However it causes problme once not_used members are
removed from NODE_STR.
Added by yui-knk (Kaneko Yuichiro) almost 2 years ago
Check node type before accessing nd_next
This is also a preparation for removing not_used members from
STR NODE. Current codes work without node type check because NODE_STR
has not_used2 member corresponding to nd_next of NODE_LIST and
NODE_DSTR. However it causes problme once not_used members are
removed from NODE_STR.