- we've come up with a different way to do #2670, which was the original
"hard" way, seems to be working.
- try to get docs and tests going for the new declared_attr stuff.
A little concerned that the number of variations is going out of control,
need to get the docs into shape in a big way.   Probably are not going to
stress the new modifiers that much, as they really aren't needed in the
vast majority of cases.   Maybe we want to make memoization the default
for declared_attr across the board, though.