message: handle EndRegion as no-op
diff: @@ -141,6 +141,8 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
  self.deallocate_local(old_val)?;
  }
  + EndRegion(..) => {}
  +
  // Defined to do nothing. These are added by optimization passes, to avoid changing the
  // size of MIR constantly.
  Nop => {}
  