Fix Trac #4917: try a bit harder to unify on-the-fly

[ghc-hetmet.git] / compiler / coreSyn / CoreUtils.lhs

diff --git a/compiler/coreSyn/CoreUtils.lhs b/compiler/coreSyn/CoreUtils.lhs
index 69a5135..2cf8885 100644 (file)
--- a/compiler/coreSyn/CoreUtils.lhs
+++ b/compiler/coreSyn/CoreUtils.lhs
@@ -25,7 +25,8 @@ module CoreUtils (
 
        -- * Properties of expressions
        exprType, coreAltType, coreAltsType,
-       exprIsDupable, exprIsTrivial, exprIsCheap, exprIsExpandable,
+       exprIsDupable, exprIsTrivial, 
+        exprIsCheap, exprIsExpandable, exprIsCheap', CheapAppFun,
        exprIsHNF, exprOkForSpeculation, exprIsBig, exprIsConLike,
        rhsIsStatic, isCheapApp, isExpandableApp,
 
@@ -513,8 +514,8 @@ exprIsCheap = exprIsCheap' isCheapApp
 exprIsExpandable :: CoreExpr -> Bool
 exprIsExpandable = exprIsCheap' isExpandableApp        -- See Note [CONLIKE pragma] in BasicTypes
 
-
-exprIsCheap' :: (Id -> Int -> Bool) -> CoreExpr -> Bool
+type CheapAppFun = Id -> Int -> Bool
+exprIsCheap' :: CheapAppFun -> CoreExpr -> Bool
 exprIsCheap' _          (Lit _)   = True
 exprIsCheap' _          (Type _)  = True
 exprIsCheap' _          (Var _)   = True
@@ -548,7 +549,7 @@ exprIsCheap' good_app other_expr    -- Applications and variables
     go (Var _) [] = True       -- Just a type application of a variable
                                -- (f t1 t2 t3) counts as WHNF
     go (Var f) args
-       = case idDetails f of
+        = case idDetails f of
                RecSelId {}                  -> go_sel args
                ClassOpId {}                 -> go_sel args
                PrimOpId op                  -> go_primop op args
@@ -582,12 +583,12 @@ exprIsCheap' good_app other_expr  -- Applications and variables
                -- BUT: Take care with (sel d x)!  The (sel d) might be cheap, but
                --      there's no guarantee that (sel d x) will be too.  Hence (n_val_args == 1)
 
-isCheapApp :: Id -> Int -> Bool
+isCheapApp :: CheapAppFun
 isCheapApp fn n_val_args
   = isDataConWorkId fn 
   || n_val_args < idArity fn
 
-isExpandableApp :: Id -> Int -> Bool
+isExpandableApp :: CheapAppFun
 isExpandableApp fn n_val_args
   =  isConLikeId fn
   || n_val_args < idArity fn
@@ -692,7 +693,7 @@ exprOkForSpeculation other_expr
                                -- A bit conservative: we don't really need
                                -- to care about lazy arguments, but this is easy
 
-    spec_ok (DFunId new_type) _ = not new_type 
+    spec_ok (DFunId _ new_type) _ = not new_type
          -- DFuns terminate, unless the dict is implemented with a newtype
         -- in which case they may not