getArgsAndRun method Null safety
override
Get the arguments described by Arg, and then run it.
Implementation
@override
void getArgsAndRun(Operation op, Arg arg, Resting fromState) {
assert(state == fromState);
assert(_argValue != _dummy);
fromState.calculate(op, _argValue);
real.doDeferred();
assert((_argValue = _dummy) == _dummy); // Reset _argValue if in debug mode
// If not in debug mode, leaving _argValue pointing to a stray ArgDone
// is harmless.
}