Simplification of instances
simonpj at microsoft.com
Fri Sep 28 18:33:25 CEST 2012
Ahem. DFuns (what you get from is_dfun of a ClsInst) now have some "silent" arguments, that are added by GHC and are not part of the original instance declaration. See
Note [Silent superclass arguments] in TcInstDcls.
But you don't want to print them. Just do what InstEnv.pprInstanceHdr does (in InstEnv) to drop the silent arguments.
I've added some more comments (commit to come).
| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-
| users-bounces at haskell.org] On Behalf Of David Waern
| Sent: 28 September 2012 10:03
| To: glasgow-haskell-users at haskell.org
| Subject: Simplification of instances
| was there a change in how GHC simplifies instances sometime between
| 7.4.1 and 7.6.1? Haddock used to produce this:
| but is now producing this:
| Haddock uses tcRnGetInfo to get the instances.
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