1 Verification Error (unit %s/rx/body/prop_write_on_return_value_unset.php func bad): property writes are only allowed on mutable values in Rx functions: UnsetM
3 Verification failed for unit %s/rx/body/prop_write_on_return_value_unset.php. Re-run with HHVM_VERIFY_VERBOSE=1 to see more details.