[commit: ghc] wip/nfs-locking: Add comments. (6482e6a)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/nfs-locking
Link       : http://ghc.haskell.org/trac/ghc/changeset/6482e6a90e68c54b7d0202d0ae5d9d600873646d/ghc

>---------------------------------------------------------------

commit 6482e6a90e68c54b7d0202d0ae5d9d600873646d
Author: Andrey Mokhov <andrey.mokhov at gmail.com>
Date:   Sun Feb 14 21:18:57 2016 +0000

    Add comments.


>---------------------------------------------------------------

6482e6a90e68c54b7d0202d0ae5d9d600873646d
 src/Context.hs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Context.hs b/src/Context.hs
index 9bf8020..b578208 100644
--- a/src/Context.hs
+++ b/src/Context.hs
@@ -20,6 +20,8 @@ data Context = Context
 vanillaContext :: Stage -> Package -> Context
 vanillaContext s p = Context s p vanilla
 
+-- | Partial context with undefined 'Package' field. Useful for 'Packages'
+-- expressions that only read the environment and current 'Stage'.
 stageContext :: Stage -> Context
 stageContext s = vanillaContext s $ error "stageContext: package not set"