Phab vs. Trac

[Simon Peyton Jones]

| Here is my proposed answer: The Phab reviews are a good place for code-
| specific commentary/feedback but Trac is better for design issues. A rule
| of thumb might be to pretend that Phab comments are all forgotten in a
| month or two, whereas Trac comments are expected to be around in 5 years.

Good criterion.  I'm littering the Notes in GHC with references to Trac tickets, on the grounds that those tickets will be permanently available.  Let's not commit to making the Phab stuff permanently available too.  (Of course it may be.)

Simon