refactor constify most of rb_method_entry_t

Now that we have eliminated most destructive operations over the
rb_method_entry_t / rb_callable_method_entry_t, let's make them
mostly immutabe and mark them const.

One exception is rb_export_method(), which destructively modifies
visibilities of method entries.  I have left that operation as is
because I suspect that destructiveness is the nature of that
function.

1 files changed, 1 insertions, 1 deletions

diff --git a/vm.c b/vm.c
index 2483180061..16a15c2151 100644
--- a/vm.c
+++ b/vm.c
@@ -1595,7 +1595,7 @@ static enum rb_id_table_iterator_result
 check_redefined_method(ID mid, VALUE value, void *data)
 {
     VALUE klass = (VALUE)data;
-    const rb_method_entry_t *me = (rb_method_entry_t *)value;
+    const rb_method_entry_t *me = (const rb_method_entry_t *)value;
     const rb_method_entry_t *newme = rb_method_entry(klass, mid);
 
     if (newme != me) rb_vm_check_redefinition_opt_method(me, me->owner);