Make attr* methods define public methods if self in caller is not same as receiver

Previously, attr* methods could be private even if not in the
private section of a class/module block.

This uses the same approach that ruby started using for define_method
in 1fc33199736f316dd71d0c551edbf514528ddde6.

Fixes [Bug #4537]

1 files changed, 1 insertions, 1 deletions

diff --git a/vm.c b/vm.c
index 593540a32e..b4e2e3c5e6 100644
--- a/vm.c
+++ b/vm.c
@@ -1383,7 +1383,7 @@ rb_vm_cref_in_context(VALUE self, VALUE cbase)
     const rb_execution_context_t *ec = GET_EC();
     const rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);
     const rb_cref_t *cref;
-    if (cfp->self != self) return NULL;
+    if (!cfp || cfp->self != self) return NULL;
     if (!vm_env_cref_by_cref(cfp->ep)) return NULL;
     cref = vm_get_cref(cfp->ep);
     if (CREF_CLASS(cref) != cbase) return NULL;