Add {-# OPTIONS_GHC -w #-} and some blurb to all compiler modules

[ghc-hetmet.git] / compiler / deSugar / MatchLit.lhs

diff --git a/compiler/deSugar/MatchLit.lhs b/compiler/deSugar/MatchLit.lhs
index d7e8ba6..c8e8e62 100644 (file)
--- a/compiler/deSugar/MatchLit.lhs
+++ b/compiler/deSugar/MatchLit.lhs
@@ -6,6 +6,13 @@
 Pattern-matching literal patterns
 
 \begin{code}
+{-# OPTIONS_GHC -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
+-- for details
+
 module MatchLit ( dsLit, dsOverLit, hsLitKey, hsOverLitKey,
                  tidyLitPat, tidyNPat, 
                  matchLiterals, matchNPlusKPats, matchNPats ) where
@@ -27,12 +34,10 @@ import TcType
 import Type
 import PrelNames
 import TysWiredIn
-import PrelNames
 import Unique
 import Literal
 import SrcLoc
 import Ratio
-import SrcLoc
 import Outputable
 import Util
 import FastString
@@ -87,6 +92,7 @@ dsOverLit :: HsOverLit Id -> DsM CoreExpr
 -- (an expression for) the literal value itself
 dsOverLit (HsIntegral   _ lit) = dsExpr lit
 dsOverLit (HsFractional _ lit) = dsExpr lit
+dsOverLit (HsIsString   _ lit) = dsExpr lit
 \end{code}
 
 \begin{code}
@@ -109,6 +115,8 @@ hsOverLitKey (HsIntegral i _) False   = MachInt i
 hsOverLitKey (HsIntegral i _) True    = MachInt (-i)
 hsOverLitKey (HsFractional r _) False = MachFloat r
 hsOverLitKey (HsFractional r _) True  = MachFloat (-r)
+hsOverLitKey (HsIsString s _)  False  = MachStr s
+-- negated string should never happen
 \end{code}
 
 %************************************************************************
@@ -140,6 +148,7 @@ tidyNPat over_lit mb_neg eq lit_ty
   | isIntTy    lit_ty = mk_con_pat intDataCon    (HsIntPrim int_val)
   | isFloatTy  lit_ty = mk_con_pat floatDataCon  (HsFloatPrim  rat_val)
   | isDoubleTy lit_ty = mk_con_pat doubleDataCon (HsDoublePrim rat_val)
+--  | isStringTy lit_ty = mk_con_pat stringDataCon (HsStringPrim str_val)
   | otherwise        = NPat over_lit mb_neg eq lit_ty
   where
     mk_con_pat :: DataCon -> HsLit -> Pat Id
@@ -158,6 +167,11 @@ tidyNPat over_lit mb_neg eq lit_ty
     rat_val = case neg_lit of
                HsIntegral   i _ -> fromInteger i
                HsFractional f _ -> f
+       
+    str_val :: FastString
+    str_val = case neg_lit of
+               HsIsString   s _ -> s
+               _                -> error "tidyNPat"
 \end{code}
 
 
@@ -174,7 +188,8 @@ matchLiterals :: [Id]
              -> DsM MatchResult
 
 matchLiterals (var:vars) ty sub_groups
-  = do {       -- Deal with each group
+  = ASSERT( all notNull sub_groups )
+    do {       -- Deal with each group
        ; alts <- mapM match_group sub_groups
 
                -- Combine results.  For everything except String