X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDefaults.lhs;h=7335631009c7fa672eb03c2c4a05eec1ae5ac919;hb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;hp=b12cb5f7e454aaf0447a3a6d685ac6210923f0d1;hpb=1fb1ab5d53a09607e7f6d2450806760688396387;p=ghc-hetmet.git

diff --git a/ghc/compiler/typecheck/TcDefaults.lhs b/ghc/compiler/typecheck/TcDefaults.lhs
index b12cb5f..7335631 100644
--- a/ghc/compiler/typecheck/TcDefaults.lhs
+++ b/ghc/compiler/typecheck/TcDefaults.lhs
@@ -1,32 +1,26 @@
 %
-% (c) The AQUA Project, Glasgow University, 1993-1995
+% (c) The AQUA Project, Glasgow University, 1993-1998
 %
 \section[TcDefaults]{Typechecking \tr{default} declarations}
 
 \begin{code}
-#include "HsVersions.h"
-
 module TcDefaults ( tcDefaults ) where
 
-IMP_Ubiq()
+#include "HsVersions.h"
 
-import HsSyn		( HsDecl(..), TyDecl, ClassDecl, InstDecl, HsBinds,
-			  DefaultDecl(..), HsType, IfaceSig,
-			  HsExpr, HsLit, ArithSeqInfo, Fake, InPat)
-import RnHsSyn		( RenamedHsDecl(..), RenamedDefaultDecl(..) )
-import TcHsSyn		( TcIdOcc )
+import HsSyn		( HsDecl(..), DefaultDecl(..) )
+import RnHsSyn		( RenamedHsDecl )
 
 import TcMonad
-import Inst		( InstOrigin(..) )
 import TcEnv		( tcLookupClassByKey )
-import SpecEnv		( SpecEnv )
 import TcMonoType	( tcHsType )
 import TcSimplify	( tcSimplifyCheckThetas )
 
-import TysWiredIn	( intTy, doubleTy, unitTy )
+import TysWiredIn	( intTy, doubleTy )
+import Type             ( Type )
 import Unique		( numClassKey )
-import Pretty		( ppPStr, ppAboves )
 import ErrUtils		( addShortErrLocLine )
+import Outputable
 import Util
 \end{code}
 
@@ -52,25 +46,28 @@ tc_defaults [DefaultDecl mono_tys locn]
 	    -- Check that all the types are instances of Num
 	    -- We only care about whether it worked or not
 
-	tcLookupClassByKey numClassKey			`thenNF_Tc` \ num ->
+	tcAddErrCtxt defaultDeclCtxt		$
+	tcLookupClassByKey numClassKey		`thenNF_Tc` \ num ->
 	tcSimplifyCheckThetas
-		[ (num, ty) | ty <- tau_tys ]		`thenTc_`
+		[{- Nothing given -}]
+		[ (num, [ty]) | ty <- tau_tys ]	`thenTc_`
 
 	returnTc tau_tys
 
 tc_defaults decls
-  = failTc (dupDefaultDeclErr decls)
+  = failWithTc (dupDefaultDeclErr decls)
 
 
-dupDefaultDeclErr (DefaultDecl _ locn1 : dup_things) sty
-  = ppAboves (item1 : map dup_item dup_things)
+defaultDeclCtxt =  ptext SLIT("when checking that each type in a default declaration")
+		    $$ ptext SLIT("is an instance of class Num")
+
+
+dupDefaultDeclErr (DefaultDecl _ locn1 : dup_things)
+  = vcat (item1 : map dup_item dup_things)
   where
     item1
-      = addShortErrLocLine locn1 (\ sty ->
-	ppPStr SLIT("multiple default declarations")) sty
+      = addShortErrLocLine locn1 (ptext SLIT("multiple default declarations"))
 
     dup_item (DefaultDecl _ locn)
-      = addShortErrLocLine locn (\ sty ->
-	ppPStr SLIT("here was another default declaration")) sty
-
+      = addShortErrLocLine locn (ptext SLIT("here was another default declaration"))
 \end{code}