Set the ORPHAN flag in `Proc.new`; fix #3798

src/proc.c

@@ -163,7 +163,11 @@ mrb_proc_s_new(mrb_state *mrb, mrb_value proc_class)
   p = (struct RProc *)mrb_obj_alloc(mrb, MRB_TT_PROC, mrb_class_ptr(proc_class));
   mrb_proc_copy(p, mrb_proc_ptr(blk));
   proc = mrb_obj_value(p);
-  mrb_funcall_with_block(mrb, proc, mrb_intern_lit(mrb, "initialize"), 0, NULL, blk);
+  mrb_funcall_with_block(mrb, proc, mrb_intern_lit(mrb, "initialize"), 0, NULL, proc);
+  if (!MRB_PROC_STRICT_P(p) &&
+      mrb->c->ci > mrb->c->cibase && p->env == mrb->c->ci[-1].env) {
+    p->flags |= MRB_PROC_ORPHAN;
+  }
   return proc;
 }