Ractor.make_shareable(a_proc)

Ractor.make_shareable() supports Proc object if
(1) a Proc only read outer local variables (no assignments)
(2) read outer local variables are shareable.

Read local variables are stored in a snapshot, so after making
shareable Proc, any assignments are not affeect like that:

```ruby
a = 1
pr = Ractor.make_shareable(Proc.new{p a})
pr.call #=> 1
a = 2
pr.call #=> 1 # `a = 2` doesn't affect
```

[Feature #17284]

1 files changed, 4 insertions, 2 deletions

diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 7d4109a4c1..51b3c40010 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -2688,13 +2688,15 @@ vm_call_bmethod_body(rb_execution_context_t *ec, struct rb_calling_info *calling
     VALUE val;
     const struct rb_callcache *cc = cd->cc;
     const rb_callable_method_entry_t *cme = vm_cc_cme(cc);
+    VALUE procv = cme->def->body.bmethod.proc;
 
-    if (cme->def->body.bmethod.defined_ractor != rb_ec_ractor_ptr(ec)->self) {
+    if (!RB_OBJ_SHAREABLE_P(procv) &&
+        cme->def->body.bmethod.defined_ractor != rb_ec_ractor_ptr(ec)->self) {
         rb_raise(rb_eRuntimeError, "defined in a different Ractor");
     }
 
     /* control block frame */
-    GetProcPtr(cme->def->body.bmethod.proc, proc);
+    GetProcPtr(procv, proc);
     val = rb_vm_invoke_bmethod(ec, proc, calling->recv, calling->argc, argv, calling->kw_splat, calling->block_handler, vm_cc_cme(cc));
 
     return val;