[project @ 2000-10-12 12:32:11 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcDefaults.lhs b/ghc/compiler/typecheck/TcDefaults.lhs
index 0d58fb5..d44bebc 100644 (file)
--- a/ghc/compiler/typecheck/TcDefaults.lhs
+++ b/ghc/compiler/typecheck/TcDefaults.lhs
@@ -12,7 +12,7 @@ import HsSyn          ( HsDecl(..), DefaultDecl(..) )
 import RnHsSyn         ( RenamedHsDecl )
 
 import TcMonad
-import TcEnv           ( tcLookupClassByKey_maybe )
+import TcEnv           ( tcLookupGlobal_maybe )
 import TcMonoType      ( tcHsType )
 import TcSimplify      ( tcSimplifyCheckThetas )
 
@@ -26,7 +26,7 @@ import Outputable
 default_default = [integerTy, doubleTy]
 
 tcDefaults :: [RenamedHsDecl]
-          -> TcM s [Type]          -- defaulting types to heave
+          -> TcM [Type]            -- defaulting types to heave
                                    -- into Tc monad for later use
                                    -- in Disambig.
 tcDefaults decls = tc_defaults [default_decl | DefD default_decl <- decls]
@@ -37,29 +37,29 @@ tc_defaults [DefaultDecl [] locn]
   = returnTc []                -- no defaults
 
 tc_defaults [DefaultDecl mono_tys locn]
-  = tcLookupClassByKey_maybe numClassKey       `thenNF_Tc` \ maybe_num ->
+  = tcLookupGlobal_maybe numClassName  `thenNF_Tc` \ maybe_num ->
     case maybe_num of {
-       Nothing ->      -- Num has not been sucked in, so the defaults will
-                       -- never be used; so simply discard the default decl.
-                       -- This slightly benefits modules that don't use any
-                       -- numeric stuff at all, by avoid the necessity of
-                       -- always sucking in Num
-               returnTc [] ;
-
-       Just num ->     -- The common case
-
-    tcAddSrcLoc locn $
-    mapTc tcHsType mono_tys    `thenTc` \ tau_tys ->
-
-           -- Check that all the types are instances of Num
-           -- We only care about whether it worked or not
-    tcAddErrCtxt defaultDeclCtxt               $
-    tcSimplifyCheckThetas
-               [{- Nothing given -}]
-               [ (num, [ty]) | ty <- tau_tys ] `thenTc_`
-
-    returnTc tau_tys
-    }
+       Just (AClass num_class) -> common_case num_class
+       other                   -> returnTc [] ;
+               -- In the Nothing case, Num has not been sucked in, so the 
+               -- defaults will never be used; so simply discard the default decl.
+               -- This slightly benefits modules that don't use any
+               -- numeric stuff at all, by avoid the necessity of
+               -- always sucking in Num
+  where
+    common_case num_class
+      = tcAddSrcLoc locn $
+       mapTc tcHsType mono_tys `thenTc` \ tau_tys ->
+    
+               -- Check that all the types are instances of Num
+               -- We only care about whether it worked or not
+       tcAddErrCtxt defaultDeclCtxt            $
+       tcSimplifyCheckThetas
+                   [{- Nothing given -}]
+                   [ (num_class, [ty]) | ty <- tau_tys ]       `thenTc_`
+    
+       returnTc tau_tys
+       }
 
 tc_defaults decls@(DefaultDecl _ loc : _) =
     tcAddSrcLoc loc $