Introduce Ractor::IsolationError

Ractor has several restrictions to keep each ractor being isolated
and some operation such as `CONST="foo"` in non-main ractor raises
an exception. This kind of operation raises an error but there is
confusion (some code raises RuntimeError and some code raises
NameError).

To make clear we introduce Ractor::IsolationError which is raised
when the isolation between ractors is violated.

1 files changed, 1 insertions, 0 deletions

diff --git a/vm_core.h b/vm_core.h
index 8540f8d1de..453c84e394 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -2011,6 +2011,7 @@ extern void rb_reset_coverages(void);
 void rb_postponed_job_flush(rb_vm_t *vm);
 
 extern VALUE rb_eRactorUnsafeError; // ractor.c
+extern VALUE rb_eRactorIsolationError;
 
 RUBY_SYMBOL_EXPORT_END