[project @ 1996-03-19 08:58:34 by partain]

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

diff --git a/ghc/compiler/typecheck/TcDefaults.lhs b/ghc/compiler/typecheck/TcDefaults.lhs
index 811f04b..5ea9905 100644 (file)
--- a/ghc/compiler/typecheck/TcDefaults.lhs
+++ b/ghc/compiler/typecheck/TcDefaults.lhs
@@ -8,60 +8,48 @@
 
 module TcDefaults ( tcDefaults ) where
 
-import TcMonad
-import AbsSyn
+import Ubiq
+
+import HsSyn           ( DefaultDecl(..), MonoType,
+                         HsExpr, HsLit, ArithSeqInfo, Fake, InPat)
+import RnHsSyn         ( RenamedDefaultDecl(..) )
+import TcHsSyn         ( TcIdOcc )
 
-import AbsPrel         ( intTy, doubleTy, unitTy )
-import AbsUniType      ( UniType
-                         IF_ATTACK_PRAGMAS(COMMA cmpUniType)
-                       )
-import CE              ( lookupCE, CE(..) )
-import E
-import Inst
-import Name
+import TcMonad
+import Inst            ( InstOrigin(..) )
+import TcEnv           ( tcLookupClassByKey )
 import TcMonoType      ( tcMonoType )
 import TcSimplify      ( tcSimplifyCheckThetas )
-import TVE
-import Unique          ( numClassKey, Unique )
+
+import PrelInfo                ( intTy, doubleTy, unitTy )
+import Unique          ( numClassKey )
 import Util
 \end{code}
 
 \begin{code}
-tcDefaults :: E
-          -> [RenamedDefaultDecl]
-          -> TcM [UniType]         -- defaulting types to heave
+tcDefaults :: [RenamedDefaultDecl]
+          -> TcM s [Type]          -- defaulting types to heave
                                    -- into Tc monad for later use
                                    -- in Disambig.
 
-tcDefaults _ []
-  = returnTc [intTy, doubleTy] -- language-specified default `default'
+tcDefaults []
+  = returnTc [intTy, doubleTy]             -- language-specified default `default'
 
-tcDefaults e [DefaultDecl mono_tys locn]
-  = let
-       ce  = getE_CE  e
-       tce = getE_TCE e
-       tve = nullTVE
+tcDefaults [DefaultDecl mono_tys locn]
+  = tcAddSrcLoc locn $
+    mapTc tcMonoType mono_tys  `thenTc` \ tau_tys ->
 
-       num_clas = lookupCE ce (PreludeClass numClassKey (panic "tcDefaults"))
-    in
-    babyTcMtoTcM (mapB_Tc (tcMonoType ce tce tve) mono_tys) `thenTc` \ tau_tys ->
-
-       -- compensate for extreme parser hack: `default ()' actually
-       -- sends the *type* () through to here.  Squash it.
     case tau_tys of
-      [ty] | ty == unitTy -> returnTc []
-
-      _  -> -- (Back to your regularly scheduled programming...)
+      [] -> returnTc []                -- no defaults
 
+      _  ->
            -- Check that all the types are instances of Num
-
-       tcSimplifyCheckThetas (DefaultDeclOrigin locn)
-                        [ (num_clas, ty) | ty <- tau_tys ] `thenTc` \ _ ->
            -- We only care about whether it worked or not
 
-       returnTc tau_tys -- caller will bung them into Tc monad
+       tcLookupClassByKey numClassKey                  `thenNF_Tc` \ num ->
+       tcSimplifyCheckThetas DefaultDeclOrigin
+               [ (num, ty) | ty <- tau_tys ]           `thenTc` \ _ ->
+
+       returnTc tau_tys
 
-tcDefaults _ (_:_)
-  = error "ERROR: You can only have one `default' declaration per module."
-    -- ToDo: proper error msg.
 \end{code}