X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcRnTypes.lhs;h=721f0782812ef604d358937db4051d848d8a90c8;hb=ef6d82a4e1d4ba4884c322be85cff291e017f0e6;hp=641319fce3073db755bed12a6aef09ca0365484c;hpb=4e0c994eb1613c62e94069642d7acdb2e69b773b;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcRnTypes.lhs b/compiler/typecheck/TcRnTypes.lhs
index 641319f..721f078 100644
--- a/compiler/typecheck/TcRnTypes.lhs
+++ b/compiler/typecheck/TcRnTypes.lhs
@@ -37,7 +37,7 @@ module TcRnTypes(
 	Implication(..), 
         CtLoc(..), ctLocSpan, ctLocOrigin, setCtLocOrigin,
 	CtOrigin(..), EqOrigin(..), 
-	WantedLoc, GivenLoc,
+        WantedLoc, GivenLoc, pushErrCtxt,
 
 	SkolemInfo(..),
 
@@ -217,22 +217,13 @@ data TcGblEnv
           --
           --   * Top-level variables appearing free in a TH bracket
 
-	tcg_inst_uses :: TcRef NameSet,
-          -- ^ Home-package Dfuns actually used.
-          --
-          -- Used to generate version dependencies This records usages, rather
-          -- like tcg_dus, but it has to be a mutable variable so it can be
-          -- augmented when we look up an instance.  These uses of dfuns are
-          -- rather like the free variables of the program, but are implicit
-          -- instead of explicit.
-
-	tcg_th_used :: TcRef Bool,
+        tcg_th_used :: TcRef Bool,
           -- ^ @True@ <=> Template Haskell syntax used.
           --
-          -- We need this so that we can generate a dependency on the Template
-          -- Haskell package, becuase the desugarer is going to emit loads of
-          -- references to TH symbols.  It's rather like tcg_inst_uses; the
-          -- reference is implicit rather than explicit, so we have to zap a
+          -- We need this so that we can generate a dependency on the
+          -- Template Haskell package, becuase the desugarer is going
+          -- to emit loads of references to TH symbols.  The reference
+          -- is implicit rather than explicit, so we have to zap a
           -- mutable variable.
 
 	tcg_dfun_n  :: TcRef OccSet,
@@ -879,12 +870,19 @@ ctLocOrigin (CtLoc o _ _) = o
 setCtLocOrigin :: CtLoc o -> o' -> CtLoc o'
 setCtLocOrigin (CtLoc _ s c) o = CtLoc o s c
 
+pushErrCtxt :: orig -> ErrCtxt -> CtLoc orig -> CtLoc orig
+pushErrCtxt o err (CtLoc _ s errs) = CtLoc o s (err:errs)
+
 pprArising :: CtOrigin -> SDoc
+-- Used for the main, top-level error message
+-- We've done special processing for TypeEq and FunDep origins
 pprArising (TypeEqOrigin {}) = empty
+pprArising FunDepOrigin      = empty
 pprArising orig              = text "arising from" <+> ppr orig
 
-pprArisingAt :: CtLoc CtOrigin -> SDoc
-pprArisingAt (CtLoc o s _) = sep [pprArising o, text "at" <+> ppr s]
+pprArisingAt :: Outputable o => CtLoc o -> SDoc
+pprArisingAt (CtLoc o s _) = sep [ text "arising from" <+> ppr o
+                                 , text "at" <+> ppr s]
 
 -------------------------------------------
 -- CtOrigin gives the origin of *wanted* constraints
@@ -916,9 +914,10 @@ data CtOrigin
   | StandAloneDerivOrigin -- Typechecking stand-alone deriving
   | DefaultOrigin	-- Typechecking a default decl
   | DoOrigin		-- Arising from a do expression
-  | IfOrigin      -- Arising from an if statement
+  | IfOrigin            -- Arising from an if statement
   | ProcOrigin		-- Arising from a proc expression
   | AnnOrigin           -- An annotation
+  | FunDepOrigin
 
 data EqOrigin 
   = UnifyOrigin 
@@ -953,6 +952,7 @@ pprO DoOrigin	           = ptext (sLit "a do statement")
 pprO ProcOrigin	           = ptext (sLit "a proc expression")
 pprO (TypeEqOrigin eq)     = ptext (sLit "an equality") <+> ppr eq
 pprO AnnOrigin             = ptext (sLit "an annotation")
+pprO FunDepOrigin          = ptext (sLit "a functional dependency")
 
 instance Outputable EqOrigin where
   ppr (UnifyOrigin t1 t2) = ppr t1 <+> char '~' <+> ppr t2