error: proc macro panicked
 --> tests/compile_failures/bad_overflow_setting_combinebits.rs:5:5
  |
5 |     combinebits!(overflow=explode, "aaaa aaaa");
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: Valid overflow setting value must be passed: "'explode' is an invalid overflow option. Options: 'truncate', 'panic', 'corrupt', 'saturate'."