Generics performance

[Ben Gamari]

Hi Ryan!

As you may know, we are encouraging contributors to view the 8.2 release
as a consolidation release, using it as an opportunity to optimize,
stabilize, document, and refine existing features instead of introducing
new ones.

It seems like there is plenty of optimization that could be done in your
area of generics. In particular #5642 and #11991 are quite relevant and
have been felt by a fair number of users. While compiling derived
Generic instances can necessarily produce quadratic code (see
ticket:5642#comment:8), the costs that we are seeing do seem a bit high
so perhaps there are some constant factors that we can knock down.
However, working this out will require a concerted effort.

Would you be interested in picking up this issue as a task for 8.2?

Cheers,

- Ben
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