Rules to make genericLength strict for Int/Integer lengths, see #2962

[ghc-base.git] / Data / Data.hs

diff --git a/Data/Data.hs b/Data/Data.hs
index ef44933..8c746dd 100644 (file)
--- a/Data/Data.hs
+++ b/Data/Data.hs
@@ -640,7 +640,7 @@ readConstr dt str =
       case dataTypeRep dt of
         AlgRep cons -> idx cons
         IntRep      -> mkReadCon (\i -> (mkPrimCon dt str (IntConstr i)))
-        FloatRep    -> mkReadCon (\f -> (mkPrimCon dt str (FloatConstr f)))
+        FloatRep    -> mkReadCon ffloat
         CharRep     -> mkReadCon (\c -> (mkPrimCon dt str (CharConstr c)))
         NoRep       -> Nothing
   where
@@ -658,6 +658,8 @@ readConstr dt str =
                      then Nothing
                      else Just (head fit)
 
+    ffloat :: Double -> Constr
+    ffloat =  mkPrimCon dt str . FloatConstr . toRational
 
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