Allow to include uninitialized modules [Bug #18177]

The module that is about to be included is considered initialized.

1 files changed, 2 insertions, 1 deletions

diff --git a/class.c b/class.c
index e0e8b17c94..46d44085d5 100644
--- a/class.c
+++ b/class.c
@@ -917,7 +917,8 @@ ensure_includable(VALUE klass, VALUE module)
     rb_class_modify_check(klass);
     Check_Type(module, T_MODULE);
     if (RMODULE_UNINITIALIZED(module)) {
-        rb_raise(rb_eArgError, "uninitialized module");
+        RB_OBJ_WRITE(module, &RCLASS(module)->super, 0);
+        /* no more re-initialization */
     }
     if (!NIL_P(rb_refinement_module_get_refined_class(module))) {
 	rb_raise(rb_eArgError, "refinement module is not allowed");