Add {-# OPTIONS_GHC -w #-} and some blurb to all compiler modules

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

diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs
index 863cd6d..3df2eef 100644 (file)
--- a/compiler/typecheck/TcTyClsDecls.lhs
+++ b/compiler/typecheck/TcTyClsDecls.lhs
@@ -6,6 +6,13 @@
 TcTyClsDecls: Typecheck type and class declarations
 
 \begin{code}
+{-# OPTIONS_GHC -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
+-- for details
+
 module TcTyClsDecls (
        tcTyAndClassDecls, tcFamInstDecl
     ) where
@@ -275,13 +282,8 @@ tcFamInstDecl1 (decl@TySynonym {tcdLName = L loc tc_name})
        ; t_rhs    <- tcHsKindedType k_rhs
 
          -- (3) check that 
-         --     - left-hand side contains no type family applications
-         --       (vanilla synonyms are fine, though)
-       ; mappM_ checkTyFamFreeness t_typats
-
-         --     - the right-hand side is a tau type
-       ; unless (isTauTy t_rhs) $ 
-          addErr (polyTyErr t_rhs)
+         --     - check the well-formedness of the instance
+       ; checkValidTypeInst t_typats t_rhs
 
          -- (4) construct representation tycon
        ; rep_tc_name <- newFamInstTyConName tc_name loc
@@ -317,7 +319,8 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name,
 
          -- (3) Check that
          --     - left-hand side contains no type family applications
-         --       (vanilla synonyms are fine, though)
+         --       (vanilla synonyms are fine, though, and we checked for
+         --       foralls earlier)
        ; mappM_ checkTyFamFreeness t_typats
 
         --     - we don't use GADT syntax for indexed types
@@ -354,27 +357,6 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name,
                        L _ (ConDecl { con_res = ResTyGADT _ }) : _ -> False
                        other -> True
 
--- Check that a type index does not contain any type family applications
---
--- * Earlier phases have already checked that there are no foralls in the
---   type; we also cannot have PredTys and NoteTys are being skipped by using
---   the core view. 
---
-checkTyFamFreeness :: Type -> TcM ()
-checkTyFamFreeness ty | Just (tycon, tys) <- splitTyConApp_maybe ty
-                      = if isSynTyCon tycon 
-                        then addErr $ tyFamAppInIndexErr ty
-                        else mappM_ checkTyFamFreeness tys
-                          -- splitTyConApp_maybe uses the core view; hence,
-                          -- any synonym tycon must be a family tycon
-
-                      | Just (ty1, ty2) <- splitAppTy_maybe ty
-                      = checkTyFamFreeness ty1 >> checkTyFamFreeness ty2
-
-                      | otherwise          -- only vars remaining
-                      = return ()
-
-
 -- Kind checking of indexed types
 -- -
 
@@ -1278,15 +1260,6 @@ wrongKindOfFamily family =
                 | isAlgTyCon family = ptext SLIT("data type")
                 | otherwise = pprPanic "wrongKindOfFamily" (ppr family)
 
-polyTyErr ty 
-  = hang (ptext SLIT("Illegal polymorphic type in type instance") <> colon) 4 $
-      ppr ty
-
-tyFamAppInIndexErr ty
-  = hang (ptext SLIT("Illegal type family application in type instance") <> 
-         colon) 4 $
-      ppr ty
-
 emptyConDeclsErr tycon
   = sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"),
         nest 2 $ ptext SLIT("(-XEmptyDataDecls permits this)")]