import {-# SOURCE #-} Match ( matchSinglePat )
import HsSyn ( Stmt(..), HsExpr(..), GRHSs(..), GRHS(..),
- HsMatchContext(..), Pat(..) )
+ LHsExpr, HsMatchContext(..), Pat(..) )
import CoreSyn ( CoreExpr )
import Var ( Id )
import Type ( Type )
in
returnDs match_result2
-dsGRHS kind pats rhs_ty (L loc (GRHS guard))
- = matchGuard (map unLoc guard) (DsMatchContext kind pats loc) rhs_ty
+dsGRHS kind pats rhs_ty (L loc (GRHS guards rhs))
+ = matchGuard (map unLoc guards) (DsMatchContext kind pats loc)
+ rhs rhs_ty
\end{code}
\begin{code}
matchGuard :: [Stmt Id] -- Guard
-> DsMatchContext -- Context
+ -> LHsExpr Id -- RHS
-> Type -- Type of RHS of guard
-> DsM MatchResult
-- See comments with HsExpr.Stmt re what an ExprStmt means
-- Here we must be in a guard context (not do-expression, nor list-comp)
-matchGuard [ResultStmt expr] ctx rhs_ty
- = do { core_expr <- dsLExpr expr
- ; return (cantFailMatchResult core_expr) }
+matchGuard [] ctx rhs rhs_ty
+ = do { core_rhs <- dsLExpr rhs
+ ; return (cantFailMatchResult core_rhs) }
-- ExprStmts must be guards
-- Turn an "otherwise" guard is a no-op
-matchGuard (ExprStmt (L _ (HsVar v)) _ : stmts) ctx rhs_ty
+matchGuard (ExprStmt (L _ (HsVar v)) _ _ : stmts) ctx rhs rhs_ty
| v `hasKey` otherwiseIdKey
|| v `hasKey` getUnique trueDataConId
-- trueDataConId doesn't have the same
-- unique as trueDataCon
- = matchGuard stmts ctx rhs_ty
+ = matchGuard stmts ctx rhs rhs_ty
-matchGuard (ExprStmt expr _ : stmts) ctx rhs_ty
- = matchGuard stmts ctx rhs_ty `thenDs` \ match_result ->
- dsLExpr expr `thenDs` \ pred_expr ->
+matchGuard (ExprStmt expr _ _ : stmts) ctx rhs rhs_ty
+ = matchGuard stmts ctx rhs rhs_ty `thenDs` \ match_result ->
+ dsLExpr expr `thenDs` \ pred_expr ->
returnDs (mkGuardedMatchResult pred_expr match_result)
-matchGuard (LetStmt binds : stmts) ctx rhs_ty
- = matchGuard stmts ctx rhs_ty `thenDs` \ match_result ->
+matchGuard (LetStmt binds : stmts) ctx rhs rhs_ty
+ = matchGuard stmts ctx rhs rhs_ty `thenDs` \ match_result ->
returnDs (adjustMatchResultDs (dsLet binds) match_result)
-- NB the dsLet occurs inside the match_result
-- Reason: dsLet takes the body expression as its argument
-- so we can't desugar the bindings without the
-- body expression in hand
-matchGuard (BindStmt pat bind_rhs : stmts) ctx rhs_ty
- = matchGuard stmts ctx rhs_ty `thenDs` \ match_result ->
- dsLExpr bind_rhs `thenDs` \ core_rhs ->
+matchGuard (BindStmt pat bind_rhs _ _ : stmts) ctx rhs rhs_ty
+ = matchGuard stmts ctx rhs rhs_ty `thenDs` \ match_result ->
+ dsLExpr bind_rhs `thenDs` \ core_rhs ->
matchSinglePat core_rhs ctx pat rhs_ty match_result
\end{code}