
On Sat, Jun 6, 2015 at 3:07 PM, Sven Panne
2015-06-06 0:09 GMT+02:00 Anthony Cowley
: This was stated unambiguously [...]
Looking back through the thread, this might be a bit of an exaggeration... ;-)
in the proposal and several times since then, but, just to clarify: *there is no possible breakage from this change*. In other words, the percentage of Haskell programs that will break will not be "much, much higher." It will be 0%. [...]
OK, but even if we reach consensus that the change is worthwhile (for me it's not), it's still extremely important to make this a language extension which must be explicitly declared. Otherwise there *will* be heavy breakage through transitive dependencies, cabal not being able to find an install plan, etc. As was already noted, not everybody is using the latest and greatest GHC (often for a good reason).
So in a nutshell: -0.5 from me if it's a language extension, -1000 if it's on by default.
Is there a reason you and others are singling out this extension for causing breakage? No language extension is taken into account by cabal unless you put a lower bound on base, which offends some people. If you use any extension, you are causing the exact breakage you are so concerned with! This is how cabal works and has worked: the use of a language extension does not solve this. So what are you basing all these confidently negative predictions on? If you don't like the syntax, vote -1 (current status is roughly 31-5), but don't invent technical-sounding objections. Anthony