D202: Injective type families

[Simon Peyton Jones]

Dear GHC devs

I'm sure I should know this, but if I want to build a Phab patch, to reproduce some issue (example below). How would I do that?

If Phabs were branches in the GHC repo I could say
	Git checkout phab/D202

That would be cool.  I know how to do that.

But I don't think they are.  So what do I do?

Simon

|  -----Original Message-----
|  From: noreply at phabricator.haskell.org
|  [mailto:noreply at phabricator.haskell.org]
|  Sent: 18 September 2014 09:35
|  To: Simon Peyton Jones
|  Subject: [Differential] [Commented On] D202: Injective type families
|  
|  jstolarek added a comment.
|  
|  I made two important adjustments:
|  
|  - first of all I removed the `result` from the parser and lexer.
|  Instead of `result` I'm planning to use type variable introduced by
|  the user for the result (as described in [[
|  https://ghc.haskell.org/trac/ghc/wiki/InjectiveTypeFamilies#Proposal7
|  | Proposal 7 ]] on the wiki.
|  
|  - following Richard's suggestion I changed `InjectivityInfo` to
|  contain `[Located name]` instead of `[LHsType name]`. But I keep
|  getting "Not in scope" errors. When I try to compile:
|  ```
|  type family F a :: r | r -> a where
|      F a = a
|  ```
|  I get errors that `r` and `a` are not in scope. According to my
|  tracing line 1149 of RnSource.lhs is responsible for this. I looked at
|  other code in this module and it seems to me that `bindHsTyVars`
|  should bring these variables into scope when renaming `r -> a`. I have
|  no idea why this does not happen. Simon, help?
|  
|  Also, build error reported by Harbormaster is nonsense.
|  
|  REPOSITORY
|    rGHC Glasgow Haskell Compiler
|  
|  REVISION DETAIL
|    https://phabricator.haskell.org/D202
|  
|  REPLY HANDLER ACTIONS
|    Reply to comment, or !reject, !abandon, !reclaim, !resign, !rethink,
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|  
|  To: jstolarek, simonpj, austin
|  Cc: goldfire, simonmar, ezyang, carter