inline structures data type for mruby (MRB_TT_INLINE) (fix #3237)

Inline structures have no instance variables, no finalizer, and offer as much space as possible in RBASIC object. This means 24 bytes on 64-bit platforms and 12 bytes on 32-bit platforms.
mruby-inline-struct gem is only provided for testing.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/etc.c b/src/etc.c
index 183e2f070..c89549da6 100644
--- a/src/etc.c
+++ b/src/etc.c
@@ -139,6 +139,7 @@ mrb_obj_id(mrb_value obj)
   case MRB_TT_EXCEPTION:
   case MRB_TT_FILE:
   case MRB_TT_DATA:
+  case MRB_TT_INLINE:
   default:
     return MakeID(mrb_ptr(obj));
   }