diff --git a/ghc/compiler/deSugar/MatchCon.lhs b/ghc/compiler/deSugar/MatchCon.lhs
index d572e60f3278b8dc44490c2c3a67b38ac559621a..280103b05637ec3144f6f9609bf8a119ced20a64 100644
--- a/ghc/compiler/deSugar/MatchCon.lhs
+++ b/ghc/compiler/deSugar/MatchCon.lhs
@@ -78,11 +78,10 @@ have-we-used-all-the-constructors? question; the local function
\begin{code}
matchConFamily :: [Id]
-> [EquationInfo]
- -> [EquationInfo] -- Shadows
-> DsM MatchResult
-matchConFamily (var:vars) eqns_info shadows
- = match_cons_used vars eqns_info shadows `thenDs` \ alts ->
+matchConFamily (var:vars) eqns_info
+ = match_cons_used vars eqns_info `thenDs` \ alts ->
mkCoAlgCaseMatchResult var alts
\end{code}
@@ -90,24 +89,22 @@ And here is the local function that does all the work. It is
more-or-less the @matchCon@/@matchClause@ functions on page~94 in
Wadler's chapter in SLPJ.
\begin{code}
-match_cons_used _ [{- no more eqns -}] _ = returnDs []
+match_cons_used _ [{- no more eqns -}] = returnDs []
-match_cons_used vars eqns_info@(EqnInfo (ConPat data_con _ arg_pats : ps1) _ : eqns) shadows
+match_cons_used vars eqns_info@(EqnInfo n ctx (ConPat data_con _ arg_pats : ps1) _ : eqns)
= let
(eqns_for_this_con, eqns_not_for_this_con) = splitByCon eqns_info
- (shadows_for_this_con, shadows_not_for_this_con) = splitByCon shadows
in
-- Go ahead and do the recursive call to make the alts
-- for the other ConPats in this con family...
- match_cons_used vars eqns_not_for_this_con shadows_not_for_this_con `thenDs` \ rest_of_alts ->
+ match_cons_used vars eqns_not_for_this_con `thenDs` \ rest_of_alts ->
-- Make new vars for the con arguments; avoid new locals where possible
- selectMatchVars arg_pats `thenDs` \ new_vars ->
+ selectMatchVars arg_pats `thenDs` \ new_vars ->
-- Now do the business to make the alt for _this_ ConPat ...
match (new_vars++vars)
- (map shift_con_pat eqns_for_this_con)
- (map shift_con_pat shadows_for_this_con) `thenDs` \ match_result ->
+ (map shift_con_pat eqns_for_this_con) `thenDs` \ match_result ->
returnDs (
(data_con, new_vars, match_result)
@@ -116,21 +113,18 @@ match_cons_used vars eqns_info@(EqnInfo (ConPat data_con _ arg_pats : ps1) _ : e
where
splitByCon :: [EquationInfo] -> ([EquationInfo], [EquationInfo])
splitByCon [] = ([],[])
- splitByCon (info@(EqnInfo (pat : _) _) : rest)
+ splitByCon (info@(EqnInfo _ _ (pat : _) _) : rest)
= case pat of
ConPat n _ _ | n == data_con -> (info:rest_yes, rest_no)
- WildPat _ -> (info:rest_yes, info:rest_no)
- -- WildPats will be in the shadows only,
- -- and they go into both groups
other_pat -> (rest_yes, info:rest_no)
where
(rest_yes, rest_no) = splitByCon rest
shift_con_pat :: EquationInfo -> EquationInfo
- shift_con_pat (EqnInfo (ConPat _ _ pats': pats) match_result)
- = EqnInfo (pats' ++ pats) match_result
- shift_con_pat (EqnInfo (WildPat _: pats) match_result) -- Will only happen in shadow
- = EqnInfo ([WildPat (outPatType arg_pat) | arg_pat <- arg_pats] ++ pats) match_result
+ shift_con_pat (EqnInfo n ctx (ConPat _ _ pats': pats) match_result)
+ = EqnInfo n ctx (pats' ++ pats) match_result
+ shift_con_pat (EqnInfo n ctx (WildPat _: pats) match_result) -- Will only happen in shadow
+ = EqnInfo n ctx ([WildPat (outPatType arg_pat) | arg_pat <- arg_pats] ++ pats) match_result
shift_con_pat other = panic "matchConFamily:match_cons_used:shift_con_pat"
\end{code}
diff --git a/ghc/compiler/deSugar/MatchLit.lhs b/ghc/compiler/deSugar/MatchLit.lhs
index 4a429fe51c1271e44a1eecda5347b243aff4b300..8b40044a3d6c9be489b95b65a3a01a7c977ac951 100644
--- a/ghc/compiler/deSugar/MatchLit.lhs
+++ b/ghc/compiler/deSugar/MatchLit.lhs
@@ -36,7 +36,6 @@ import Util ( panic, assertPanic )
\begin{code}
matchLiterals :: [Id]
-> [EquationInfo]
- -> [EquationInfo] -- Shadows
-> DsM MatchResult
\end{code}
@@ -48,28 +47,26 @@ is much like @matchConFamily@, which uses @match_cons_used@ to create
the alts---here we use @match_prims_used@.
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo (LitPat literal lit_ty : ps1) _ : eqns) shadows
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_ty : ps1) _ : eqns)
= -- GENERATE THE ALTS
- match_prims_used vars eqns_info shadows `thenDs` \ prim_alts ->
+ match_prims_used vars eqns_info `thenDs` \ prim_alts ->
-- MAKE THE PRIMITIVE CASE
mkCoPrimCaseMatchResult var prim_alts
where
- match_prims_used _ [{-no more eqns-}] _ = returnDs []
+ match_prims_used _ [{-no more eqns-}] = returnDs []
- match_prims_used vars eqns_info@(EqnInfo ((LitPat literal lit_ty):ps1) _ : eqns) shadows
+ match_prims_used vars eqns_info@(EqnInfo n ctx ((LitPat literal lit_ty):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit Nothing literal eqns_info
- (shifted_shadows_for_this_lit, shadows_not_for_this_lit)
- = partitionEqnsByLit Nothing literal shadows
in
-- recursive call to make other alts...
- match_prims_used vars eqns_not_for_this_lit shadows_not_for_this_lit `thenDs` \ rest_of_alts ->
+ match_prims_used vars eqns_not_for_this_lit `thenDs` \ rest_of_alts ->
-- (prim pats have no args; no selectMatchVars as in match_cons_used)
-- now do the business to make the alt for _this_ LitPat ...
- match vars shifted_eqns_for_this_lit shifted_shadows_for_this_lit `thenDs` \ match_result ->
+ match vars shifted_eqns_for_this_lit `thenDs` \ match_result ->
returnDs (
(mk_core_lit lit_ty literal, match_result)
: rest_of_alts
@@ -88,22 +85,20 @@ matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo (LitPat literal lit_ty : ps
\end{code}
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo ((NPat literal lit_ty eq_chk):ps1) _ : eqns) shadows
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx ((NPat literal lit_ty eq_chk):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit Nothing literal eqns_info
- (shifted_shadows_for_this_lit, shadows_not_for_this_lit)
- = partitionEqnsByLit Nothing literal shadows
in
- dsExpr (HsApp eq_chk (HsVar var)) `thenDs` \ pred_expr ->
- match vars shifted_eqns_for_this_lit shifted_shadows_for_this_lit `thenDs` \ inner_match_result ->
- mkGuardedMatchResult pred_expr inner_match_result `thenDs` \ match_result1 ->
+ dsExpr (HsApp eq_chk (HsVar var)) `thenDs` \ pred_expr ->
+ match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result ->
+ mkGuardedMatchResult pred_expr inner_match_result `thenDs` \ match_result1 ->
if (null eqns_not_for_this_lit)
then
returnDs match_result1
else
- matchLiterals all_vars eqns_not_for_this_lit shadows_not_for_this_lit `thenDs` \ match_result2 ->
+ matchLiterals all_vars eqns_not_for_this_lit `thenDs` \ match_result2 ->
combineMatchResults match_result1 match_result2
\end{code}
@@ -119,14 +114,12 @@ We generate:
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo ((NPlusKPat master_n k ty ge sub):ps1) _ : eqns) shadows
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx ((NPlusKPat master_n k ty ge sub):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit (Just master_n) k eqns_info
- (shifted_shadows_for_this_lit, shadows_not_for_this_lit)
- = partitionEqnsByLit (Just master_n) k shadows
in
- match vars shifted_eqns_for_this_lit shifted_shadows_for_this_lit `thenDs` \ inner_match_result ->
+ match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result ->
dsExpr (HsApp ge (HsVar var)) `thenDs` \ ge_expr ->
dsExpr (HsApp sub (HsVar var)) `thenDs` \ nminusk_expr ->
@@ -140,7 +133,7 @@ matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo ((NPlusKPat master_n k ty g
then
returnDs match_result1
else
- matchLiterals all_vars eqns_not_for_this_lit shadows_not_for_this_lit `thenDs` \ match_result2 ->
+ matchLiterals all_vars eqns_not_for_this_lit `thenDs` \ match_result2 ->
combineMatchResults match_result1 match_result2
\end{code}
@@ -168,24 +161,24 @@ partitionEqnsByLit nPlusK lit eqns
partition_eqn :: Maybe Id -> HsLit -> EquationInfo ->
(Maybe EquationInfo, Maybe EquationInfo)
- partition_eqn Nothing lit (EqnInfo (LitPat k _ : remaining_pats) match_result)
- | lit `eq_lit` k = (Just (EqnInfo remaining_pats match_result), Nothing)
+ partition_eqn Nothing lit (EqnInfo n ctx (LitPat k _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
- partition_eqn Nothing lit (EqnInfo (NPat k _ _ : remaining_pats) match_result)
- | lit `eq_lit` k = (Just (EqnInfo remaining_pats match_result), Nothing)
+ partition_eqn Nothing lit (EqnInfo n ctx (NPat k _ _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
- partition_eqn (Just master_n) lit (EqnInfo (NPlusKPat n k _ _ _ : remaining_pats) match_result)
- | lit `eq_lit` k = (Just (EqnInfo remaining_pats new_match_result), Nothing)
+ partition_eqn (Just master_n) lit (EqnInfo n ctx (NPlusKPat n' k _ _ _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats new_match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
where
- new_match_result | master_n == n = match_result
- | otherwise = mkCoLetsMatchResult [NonRec n (Var master_n)] match_result
+ new_match_result | master_n == n' = match_result
+ | otherwise = mkCoLetsMatchResult [NonRec n' (Var master_n)] match_result
-- Wild-card patterns, which will only show up in the shadows, go into both groups
- partition_eqn nPlusK lit eqn@(EqnInfo (WildPat _ : remaining_pats) match_result)
- = (Just (EqnInfo remaining_pats match_result), Just eqn)
+ partition_eqn nPlusK lit eqn@(EqnInfo n ctx (WildPat _ : remaining_pats) match_result)
+ = (Just (EqnInfo n ctx remaining_pats match_result), Just eqn)
-- Default case; not for this pattern
partition_eqn nPlusK lit eqn = (Nothing, Just eqn)