Simon Peyton Jones
My conclusion
* I think we (collectively!) should make a serious attempt to fix show-stopping bugs on a major release branch. (I agree that upgrading to the next major release often simply brings in a new wave of bugs because of GHC's rapid development culture.)
* We can only possibly do this if a) we can distinguish "show-stopping" from "nice to have" b) we get some help (thank you John Lato for implicitly offering)
I would define a "show-stopping" bug as one that simply prevents you from using the release altogether, or imposes a very large cost at the user end.
For mechanism I suggest this. On the 7.8.4 status page (or in general, on the release branch page you want to influence), create a section "Show stoppers" with a list of the show-stopping bugs, including some English-language text saying who cares so much and why. (Yes I know that it might be there in the ticket, but the impact is much greater if there is an explicit list of two or three personal statements up front.)
Writing a bit more text sounds like a small price to pay to ensure that show-stoppers don't fall through the cracks. It's also nice to have a high-level view of what is being considered for release. I've added some text for #9439 [1].
Concerning 7.8.4 itself, I think we could review the decision to abandon it, in the light of new information. We might, for example, fix show-stoppers, include fixes that are easy to apply, and not-include other fixes that are harder.
This seems quite reasonable. Cheers, - Ben [1] https://ghc.haskell.org/trac/ghc/wiki/Status/GHC-7.8.4#a9439:LLVMmanglermang...