[project @ 1997-12-02 18:11:33 by quintela]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcGRHSs.lhs

diff --git a/ghc/compiler/typecheck/TcGRHSs.lhs b/ghc/compiler/typecheck/TcGRHSs.lhs
index a66c33a..0a0b58e 100644 (file)
--- a/ghc/compiler/typecheck/TcGRHSs.lhs
+++ b/ghc/compiler/typecheck/TcGRHSs.lhs
@@ -4,54 +4,59 @@
 \section[TcGRHSs]{Typecheck guarded right-hand-sides}
 
 \begin{code}
-module TcGRHSs ( tcGRHSsAndBinds ) where
+#include "HsVersions.h"
 
-import TcMonad         -- typechecking monad machinery
-import AbsSyn          -- the stuff being typechecked
-
-import AbsPrel         ( boolTy )
-import E               ( growE_LVE, E, LVE(..), TCE(..), UniqFM, CE(..) )
-                       -- TCE and CE for pragmas only
-import Errors          ( UnifyErrContext(..) )
-import LIE             ( plusLIE, LIE )
-import TcBinds         ( tcLocalBindsAndThen )
-import TcExpr          ( tcExpr )
-import Unify           ( unifyTauTy )
-import Util            -- pragmas only
-\end{code}
+module TcGRHSs ( tcGRHSsAndBinds ) where
 
-\begin{code}
-tcGRHSs :: E -> [RenamedGRHS] -> TcM ([TypecheckedGRHS], LIE, UniType)
+IMP_Ubiq(){-uitous-}
+#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
+IMPORT_DELOOPER(TcLoop) -- for paranoia checking
+#endif
 
-tcGRHSs e [grhs]
-  = tcGRHS e grhs      `thenTc` \ (grhs', lie, ty) ->
-    returnTc ([grhs'], lie, ty)
+import HsSyn           ( GRHSsAndBinds(..), GRHS(..), MonoBinds, Stmt, DoOrListComp(..),
+                         HsExpr, HsBinds(..), InPat, OutPat, Sig, Fake )
+import RnHsSyn         ( SYN_IE(RenamedGRHSsAndBinds), SYN_IE(RenamedGRHS) )
+import TcHsSyn         ( SYN_IE(TcGRHSsAndBinds), SYN_IE(TcGRHS) )
 
-tcGRHSs e gs@(grhs:grhss)
-  = tcGRHS  e grhs     `thenTc` \ (grhs',  lie1, ty1) ->
-    tcGRHSs e grhss    `thenTc` \ (grhss', lie2, ty2) ->
+import TcMonad
+import Inst            ( Inst, SYN_IE(LIE), plusLIE )
+import Kind             ( mkTypeKind )
+import TcBinds         ( tcBindsAndThen )
+import TcExpr          ( tcExpr, tcStmt )
+import TcType          ( SYN_IE(TcType), TcIdOcc(..), newTyVarTy ) 
 
-    unifyTauTy ty1 ty2 (GRHSsBranchCtxt gs) `thenTc_`
+import TysWiredIn      ( boolTy )
+\end{code}
 
-    returnTc (grhs' : grhss', lie1 `plusLIE` lie2, ty1)
+\begin{code}
+tcGRHSs :: TcType s -> [RenamedGRHS] -> TcM s ([TcGRHS s], LIE s)
 
+tcGRHSs expected_ty [grhs]
+  = tcGRHS expected_ty grhs            `thenTc` \ (grhs', lie) ->
+    returnTc ([grhs'], lie)
 
-tcGRHS e (OtherwiseGRHS expr locn)
-  = addSrcLocTc locn    (
-    tcExpr e expr      `thenTc` \ (expr, lie, ty) ->
-    returnTc (OtherwiseGRHS expr locn, lie, ty)
-    )
+tcGRHSs expected_ty (grhs:grhss)
+  = tcGRHS  expected_ty grhs   `thenTc` \ (grhs',  lie1) ->
+    tcGRHSs expected_ty grhss  `thenTc` \ (grhss', lie2) ->
+    returnTc (grhs' : grhss', lie1 `plusLIE` lie2)
 
-tcGRHS e (GRHS guard expr locn)
-  = addSrcLocTc locn            (
-    tcExpr e guard             `thenTc` \ (guard2, guard_lie, guard_ty) ->
 
-    unifyTauTy guard_ty boolTy (GRHSsGuardCtxt guard) `thenTc_`
+tcGRHS expected_ty (OtherwiseGRHS expr locn)
+  = tcAddSrcLoc locn    $
+    tcExpr expr        expected_ty        `thenTc`    \ (expr, lie) ->
+    returnTc (OtherwiseGRHS expr locn, lie)
 
-    tcExpr e expr              `thenTc` \ (expr2, expr_lie, expr_ty) ->
+tcGRHS expected_ty (GRHS guard expr locn)
+  = tcAddSrcLoc locn           $
+    tc_stmts  guard    `thenTc` \ ((guard', expr'), lie) ->
+    returnTc (GRHS guard' expr' locn, lie)
+  where
+    tc_stmts []                  = tcExpr expr expected_ty       `thenTc`    \ (expr2, expr_lie) ->
+                           returnTc (([], expr2), expr_lie)
+    tc_stmts (stmt:stmts) = tcStmt tcExpr Guard (\x->x) combine stmt $
+                           tc_stmts stmts
 
-    returnTc (GRHS guard2 expr2 locn, plusLIE guard_lie expr_lie, expr_ty)
-    )
+    combine stmt _ (stmts, expr) = (stmt:stmts, expr)
 \end{code}
 
 
@@ -59,18 +64,17 @@ tcGRHS e (GRHS guard expr locn)
 pieces.
 
 \begin{code}
-tcGRHSsAndBinds :: E 
+tcGRHSsAndBinds :: TcType s                    -- Expected type of RHSs
                -> RenamedGRHSsAndBinds
-               -> TcM (TypecheckedGRHSsAndBinds, LIE, UniType)
-
-tcGRHSsAndBinds e (GRHSsAndBindsIn grhss binds)
-  = tcLocalBindsAndThen e 
-        combiner binds 
-        (\e -> tcGRHSs e grhss         `thenTc` (\ (grhss', lie, ty) ->
-               returnTc (GRHSsAndBindsOut grhss' EmptyBinds ty, lie, ty) 
-               )
+               -> TcM s (TcGRHSsAndBinds s, LIE s)
+
+tcGRHSsAndBinds expected_ty (GRHSsAndBindsIn grhss binds)
+  = tcBindsAndThen
+        combiner binds
+        (tcGRHSs expected_ty grhss     `thenTc` \ (grhss', lie) ->
+         returnTc (GRHSsAndBindsOut grhss' EmptyBinds expected_ty, lie)
         )
   where
-    combiner binds1 (GRHSsAndBindsOut grhss binds2 ty)
-       = GRHSsAndBindsOut grhss (binds1 `ThenBinds` binds2) ty
+    combiner is_rec binds1 (GRHSsAndBindsOut grhss binds2 ty)
+       = GRHSsAndBindsOut grhss ((MonoBind binds1 [] is_rec) `ThenBinds` binds2) ty
 \end{code}