spec1.arity0 foo spec1.arity0 bar spec1.arity1 z spec1.arity1 zz spec1.plus_flags o spec1.plus_flags p spec1.defaults x spec1.defaults y sizeof 4 sizeof 3 b = 1 i = 42 b = 3.140000 b = foo .sizeof(flag_spec::_FlagSpecAndMore) = 16 alignof(flag_spec::_FlagSpecAndMore) = 4 sizeof(out) = 4 sizeof(flag_spec::_FlagSpec) = 20 alignof(flag_spec::_FlagSpec) = 4 sizeof(out2) = 4 . Total: 2 tests (857 ticks, 0.001 sec), 5 assertions Pass: 2, fail: 0, skip: 0.