Core: introduce Alt/AnnAlt/IfaceAlt datatypes

Alt, AnnAlt and IfaceAlt were using triples. This patch makes them use
dedicated types so that we can try to make some fields strict (for
example) in the future.

1 files changed, 12 insertions, 10 deletions

diff --git a/compiler/GHC/Core.hs b/compiler/GHC/Core.hs
index 523c8e3d79..230d3498ce 100644
--- a/compiler/GHC/Core.hs
+++ b/compiler/GHC/Core.hs
@@ -12,7 +12,7 @@
 -- | GHC.Core holds all the main data types for use by for the Glasgow Haskell Compiler midsection
 module GHC.Core (
         -- * Main data types
-        Expr(..), Alt, Bind(..), AltCon(..), Arg,
+        Expr(..), Alt(..), Bind(..), AltCon(..), Arg,
         Tickish(..), TickishScoping(..), TickishPlacement(..),
         CoreProgram, CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr,
         TaggedExpr, TaggedAlt, TaggedBind, TaggedArg, TaggedBndr(..), deTagExpr,
@@ -75,7 +75,7 @@ module GHC.Core (
         canUnfold, neverUnfoldGuidance, isStableSource,
 
         -- * Annotated expression data types
-        AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt,
+        AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt(..),
 
         -- ** Operations on annotated expressions
         collectAnnArgs, collectAnnArgsTicks,
@@ -282,7 +282,9 @@ type Arg b = Expr b
 
 -- If you edit this type, you may need to update the GHC formalism
 -- See Note [GHC Formalism] in GHC.Core.Lint
-type Alt b = (AltCon, [b], Expr b)
+data Alt b
+    = Alt AltCon [b] (Expr b)
+    deriving (Data)
 
 -- | A case alternative constructor (i.e. pattern match)
 
@@ -1834,10 +1836,10 @@ instance Outputable AltCon where
   ppr (LitAlt lit) = ppr lit
   ppr DEFAULT      = text "__DEFAULT"
 
-cmpAlt :: (AltCon, a, b) -> (AltCon, a, b) -> Ordering
-cmpAlt (con1, _, _) (con2, _, _) = con1 `cmpAltCon` con2
+cmpAlt :: Alt a -> Alt a -> Ordering
+cmpAlt (Alt con1 _ _) (Alt con2 _ _) = con1 `cmpAltCon` con2
 
-ltAlt :: (AltCon, a, b) -> (AltCon, a, b) -> Bool
+ltAlt :: Alt a -> Alt a -> Bool
 ltAlt a1 a2 = (a1 `cmpAlt` a2) == LT
 
 cmpAltCon :: AltCon -> AltCon -> Ordering
@@ -1936,7 +1938,7 @@ deTagBind (NonRec (TB b _) rhs) = NonRec b (deTagExpr rhs)
 deTagBind (Rec prs)             = Rec [(b, deTagExpr rhs) | (TB b _, rhs) <- prs]
 
 deTagAlt :: TaggedAlt t -> CoreAlt
-deTagAlt (con, bndrs, rhs) = (con, [b | TB b _ <- bndrs], deTagExpr rhs)
+deTagAlt (Alt con bndrs rhs) = Alt con [b | TB b _ <- bndrs] (deTagExpr rhs)
 
 {-
 ************************************************************************
@@ -2136,7 +2138,7 @@ rhssOfBind (NonRec _ rhs) = [rhs]
 rhssOfBind (Rec pairs)    = [rhs | (_,rhs) <- pairs]
 
 rhssOfAlts :: [Alt b] -> [Expr b]
-rhssOfAlts alts = [e | (_,_,e) <- alts]
+rhssOfAlts alts = [e | Alt _ _ e <- alts]
 
 -- | Collapse all the bindings in the supplied groups into a single
 -- list of lhs\/rhs pairs suitable for binding in a 'Rec' binding group
@@ -2299,7 +2301,7 @@ data AnnExpr' bndr annot
   | AnnCoercion Coercion
 
 -- | A clone of the 'Alt' type but allowing annotation at every tree node
-type AnnAlt bndr annot = (AltCon, [bndr], AnnExpr bndr annot)
+data AnnAlt bndr annot = AnnAlt AltCon [bndr] (AnnExpr bndr annot)
 
 -- | A clone of the 'Bind' type but allowing annotation at every tree node
 data AnnBind bndr annot
@@ -2344,7 +2346,7 @@ deAnnotate' (AnnCase scrut v t alts)
   = Case (deAnnotate scrut) v t (map deAnnAlt alts)
 
 deAnnAlt :: AnnAlt bndr annot -> Alt bndr
-deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
+deAnnAlt (AnnAlt con args rhs) = Alt con args (deAnnotate rhs)
 
 deAnnBind  :: AnnBind b annot -> Bind b
 deAnnBind (AnnNonRec var rhs) = NonRec var (deAnnotate rhs)