`alias` should not set `defined_class` for Modules

`me->defined_class` should be 0 for method entries of
Modules.

This patch checks this condition
and fix https://github.com/ruby/ruby/pull/11965#issuecomment-2448291790

1 files changed, 7 insertions, 1 deletions

diff --git a/vm_method.c b/vm_method.c
index 1a6e965e44..120e8b0563 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -2332,7 +2332,13 @@ rb_alias(VALUE klass, ID alias_name, ID original_name)
 
         alias_me = method_entry_set(target_klass, alias_name, orig_me, visi, orig_me->owner);
         RB_OBJ_WRITE(alias_me, &alias_me->owner, target_klass);
-        RB_OBJ_WRITE(alias_me, &alias_me->defined_class, orig_me->defined_class);
+
+        if (RB_TYPE_P(target_klass, T_MODULE)) {
+            // defined_class should not be set
+        }
+        else {
+            RB_OBJ_WRITE(alias_me, &alias_me->defined_class, orig_me->defined_class);
+        }
     }
 }