Refactor to combine two eqExpr functions

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

diff --git a/compiler/coreSyn/CoreSyn.lhs b/compiler/coreSyn/CoreSyn.lhs
index 5c7cef9..04d3906 100644 (file)
--- a/compiler/coreSyn/CoreSyn.lhs
+++ b/compiler/coreSyn/CoreSyn.lhs
@@ -43,7 +43,7 @@ module CoreSyn (
         unSaturatedOk, needSaturated, boringCxtOk, boringCxtNotOk,
        
        -- ** Predicates and deconstruction on 'Unfolding'
-       unfoldingTemplate, setUnfoldingTemplate,
+       unfoldingTemplate, setUnfoldingTemplate, expandUnfolding_maybe,
        maybeUnfoldingTemplate, otherCons, unfoldingArity,
        isValueUnfolding, isEvaldUnfolding, isCheapUnfolding,
         isExpandableUnfolding, isConLikeUnfolding, isCompulsoryUnfolding,
@@ -583,6 +583,13 @@ isExpandableUnfolding :: Unfolding -> Bool
 isExpandableUnfolding (CoreUnfolding { uf_expandable = is_expable }) = is_expable
 isExpandableUnfolding _                                              = False
 
+expandUnfolding_maybe :: Unfolding -> Maybe CoreExpr
+-- Expand an expandable unfolding; this is used in rule matching 
+--   See Note [Expanding variables] in Rules.lhs
+-- The key point here is that CONLIKE things can be expanded
+expandUnfolding_maybe (CoreUnfolding { uf_expandable = True, uf_tmpl = rhs }) = Just rhs
+expandUnfolding_maybe _                                                       = Nothing
+
 isInlineRule :: Unfolding -> Bool
 isInlineRule (CoreUnfolding { uf_src = src }) = isInlineRuleSource src
 isInlineRule _                               = False