Use rb_fstring for "defined" strings.

We can take advantage of fstrings to de-duplicate the defined strings.
This means we don't need to keep the list of defined strings on the VM
(or register them as mark objects)

1 files changed, 0 insertions, 1 deletions

diff --git a/vm_core.h b/vm_core.h
index a7644eb658..31ac4ace76 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -650,7 +650,6 @@ typedef struct rb_vm_struct {
 
     rb_at_exit_list *at_exit;
 
-    VALUE *defined_strings;
     st_table *frozen_strings;
 
     const struct rb_builtin_function *builtin_function_table;