message: Fix uninitialized access to boost::none in ConstProp
diff: @@ -1339,7 +1339,7 @@ ConstantEnvironment FixpointIterator::analyze_edge(
  // is a non-fallthrough edge with a case-key that is equal to the actual
  // selector value.
  auto scd = selector_val.maybe_get<SignedConstantDomain>();
  - auto selector_const = scd->get_constant();
  + auto selector_const = scd ? scd->get_constant() : boost::none;
  if (!selector_const) {
  return env;
  }
  