[commit: ghc] master: Comments only (bc9e81c)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/bc9e81cfe5aec2484833854ab0c1abfef9c11b0f/ghc

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

commit bc9e81cfe5aec2484833854ab0c1abfef9c11b0f
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed Dec 3 13:38:55 2014 +0000

    Comments only


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

bc9e81cfe5aec2484833854ab0c1abfef9c11b0f
 compiler/typecheck/TcInteract.lhs |  4 ++--
 libraries/ghc-prim/GHC/Types.hs   | 12 ++++++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/compiler/typecheck/TcInteract.lhs b/compiler/typecheck/TcInteract.lhs
index bfe470d..dcac915 100644
--- a/compiler/typecheck/TcInteract.lhs
+++ b/compiler/typecheck/TcInteract.lhs
@@ -1038,8 +1038,8 @@ outer type constructors match.
 
 Note [Delicate equality kick-out]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-When adding an work-item CTyEqCan (a ~ xi), we kick out an inert
-CTyEqCan (b ~ phi) when
+When adding an fully-rewritten work-item CTyEqCan (a ~ xi), we kick
+out an inert CTyEqCan (b ~ phi) when
 
   a) the work item can rewrite the inert item
 
diff --git a/libraries/ghc-prim/GHC/Types.hs b/libraries/ghc-prim/GHC/Types.hs
index e9f1428..0f1d961 100644
--- a/libraries/ghc-prim/GHC/Types.hs
+++ b/libraries/ghc-prim/GHC/Types.hs
@@ -98,11 +98,11 @@ constraints, but we cannot define them as such in Haskell. But we also cannot
 just define them only in GHC.Prim (like (->)), because we need a real module
 for them, e.g. to compile the constructor's info table.
 
-Furthermore the type of MkCoercible cannot be written in Haskell (no syntax for
-~#R).
+Furthermore the type of MkCoercible cannot be written in Haskell
+(no syntax for ~#R).
 
-So we define them as regular data types in GHC.Types, and do magic in GHC to
-change the kind and type, in tysWiredIn.
+So we define them as regular data types in GHC.Types, and do magic in TysWiredIn,
+inside GHC, to change the kind and type.
 -}
 
 
@@ -161,6 +161,10 @@ data (~) a b = Eq# ((~#) a b)
 --
 --      /Since: 4.7.0.0/
 data Coercible a b = MkCoercible ((~#) a b)
+-- It's really ~R# (represntational equality), not ~#,
+-- but  * we don't yet have syntax for ~R#,
+--      * the compiled code is the same either way
+--      * TysWiredIn has the truthful types
 -- Also see Note [Kind-changing of (~) and Coercible]
 
 -- | Alias for 'tagToEnum#'. Returns True if its parameter is 1# and False