Minor tidying up

[ghc-hetmet.git] / compiler / hsSyn / HsPat.lhs

diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs
index ee21ee3..aa1568d 100644 (file)
--- a/compiler/hsSyn/HsPat.lhs
+++ b/compiler/hsSyn/HsPat.lhs
@@ -122,14 +122,16 @@ data Pat id
 
        ------------ Dictionary patterns (translation only) ---------------
   | DictPat        -- Used when destructing Dictionaries with an explicit case
-                   [id]                        -- superclass dicts
-                   [id]                        -- methods
+                   [id]                -- Superclass dicts
+                   [id]                -- Methods
 
        ------------ Pattern coercions (translation only) ---------------
   | CoPat      ExprCoFn                -- If co::t1 -> t2, p::t2, 
                                        -- then (CoPat co p) :: t1
-               (Pat id)                -- No nested location reqd
-               Type    
+               (Pat id)                -- Why not LPat?  Ans: existing locn will do
+               Type
+       -- During desugaring a (CoPat co pat) turns into a cast with 'co' on 
+       -- the scrutinee, followed by a match on 'pat'
 \end{code}
 
 HsConDetails is use both for patterns and for data type declarations