[project @ 1999-11-29 17:34:14 by simonpj]

[ghc-hetmet.git] / ghc / compiler / rename / RnBinds.lhs

diff --git a/ghc/compiler/rename/RnBinds.lhs b/ghc/compiler/rename/RnBinds.lhs
index ab0e9ee..0036a53 100644 (file)
--- a/ghc/compiler/rename/RnBinds.lhs
+++ b/ghc/compiler/rename/RnBinds.lhs
@@ -1,5 +1,5 @@
 %
 %

-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998

 %
 \section[RnBinds]{Renaming and dependency analysis of bindings}
 
 %
 \section[RnBinds]{Renaming and dependency analysis of bindings}
 

@@ -9,37 +9,41 @@ type-synonym declarations; those cannot be done at this stage because
 they may be affected by renaming (which isn't fully worked out yet).
 
 \begin{code}
 they may be affected by renaming (which isn't fully worked out yet).
 
 \begin{code}

-#include "HsVersions.h"
-

 module RnBinds (
 module RnBinds (

-       rnTopBinds,
-       rnMethodBinds,
+       rnTopBinds, rnTopMonoBinds,
+       rnMethodBinds, renameSigs,

        rnBinds,
        rnBinds,

-       FreeVars(..),
-       DefinedVars(..)
+       unknownSigErr

    ) where
 
    ) where
 

-IMP_Ubiq()
-IMPORT_DELOOPER(RnLoop)                -- break the RnPass/RnExpr/RnBinds loops
+#include "HsVersions.h"
+
+import {-# SOURCE #-} RnSource ( rnHsSigType )

 
 import HsSyn
 
 import HsSyn

-import HsPragmas       ( isNoGenPragmas, noGenPragmas )
+import HsBinds         ( sigsForMe )

 import RdrHsSyn
 import RnHsSyn
 import RnMonad
 import RdrHsSyn
 import RnHsSyn
 import RnMonad

-import RnExpr          ( rnMatch, rnGRHSsAndBinds, rnPat, checkPrecMatch )
-
-import CmdLineOpts     ( opt_SigsRequired )
-import Digraph         ( stronglyConnComp )
-import ErrUtils                ( addErrLoc, addShortErrLocLine )
-import Name            ( RdrName )
-import Maybes          ( catMaybes )
-import PprStyle--ToDo:rm
-import Pretty
-import UniqSet         ( emptyUniqSet, unitUniqSet, mkUniqSet,
-                         unionUniqSets, unionManyUniqSets,
-                         elementOfUniqSet, uniqSetToList, UniqSet(..) )
-import Util            ( thenCmp, isIn, removeDups, panic, panic#, assertPanic, pprTrace{-ToDo:rm-} )
+import RnExpr          ( rnMatch, rnGRHSs, rnPat, checkPrecMatch )
+import RnEnv           ( bindLocatedLocalsRn, lookupBndrRn, lookupGlobalOccRn,
+                         warnUnusedLocalBinds, mapFvRn, 
+                         FreeVars, emptyFVs, plusFV, plusFVs, unitFV, addOneFV,
+                         unknownNameErr
+                       )
+import CmdLineOpts     ( opt_WarnMissingSigs )
+import Digraph         ( stronglyConnComp, SCC(..) )
+import Name            ( OccName, Name, nameOccName )
+import NameSet
+import RdrName         ( RdrName, rdrNameOcc  )
+import BasicTypes      ( RecFlag(..), TopLevelFlag(..) )
+import Util            ( thenCmp, removeDups )
+import List            ( partition )
+import ListSetOps      ( minusList )
+import Bag             ( bagToList )
+import FiniteMap       ( lookupFM, listToFM )
+import Maybe           ( isJust )
+import Outputable

 \end{code}
 
 -- ToDo: Put the annotations into the monad, so that they arrive in the proper
 \end{code}
 
 -- ToDo: Put the annotations into the monad, so that they arrive in the proper

@@ -64,15 +68,6 @@ This is precisely what the function @rnBinds@ does.
 ToDo: deal with case where a single monobinds binds the same variable
 twice.
 
 ToDo: deal with case where a single monobinds binds the same variable
 twice.
 

-Sets of variable names are represented as sets explicitly, rather than lists.
-
-\begin{code}
-type DefinedVars = UniqSet RnName
-type FreeVars    = UniqSet RnName
-\end{code}
-
-i.e., binders.
-

 The vertag tag is a unique @Int@; the tags only need to be unique
 within one @MonoBinds@, so that unique-Int plumbing is done explicitly
 (heavy monad machinery not needed).
 The vertag tag is a unique @Int@; the tags only need to be unique
 within one @MonoBinds@, so that unique-Int plumbing is done explicitly
 (heavy monad machinery not needed).

@@ -88,6 +83,7 @@ type Edge     = (VertexTag, VertexTag)
 %* naming conventions                                                  *
 %*                                                                     *
 %************************************************************************
 %* naming conventions                                                  *
 %*                                                                     *
 %************************************************************************

+

 \subsection[name-conventions]{Name conventions}
 
 The basic algorithm involves walking over the tree and returning a tuple
 \subsection[name-conventions]{Name conventions}
 
 The basic algorithm involves walking over the tree and returning a tuple

@@ -114,6 +110,7 @@ a set of variables free in @Exp@ is written @fvExp@
 %* analysing polymorphic bindings (HsBinds, Bind, MonoBinds)           *
 %*                                                                     *
 %************************************************************************
 %* analysing polymorphic bindings (HsBinds, Bind, MonoBinds)           *
 %*                                                                     *
 %************************************************************************

+

 \subsubsection[dep-HsBinds]{Polymorphic bindings}
 
 Non-recursive expressions are reconstructed without any changes at top
 \subsubsection[dep-HsBinds]{Polymorphic bindings}
 
 Non-recursive expressions are reconstructed without any changes at top

@@ -154,242 +151,264 @@ instance declarations.  It expects only to see @FunMonoBind@s, and
 it expects the global environment to contain bindings for the binders
 (which are all class operations).
 
 it expects the global environment to contain bindings for the binders
 (which are all class operations).
 

-\begin{code}
-rnTopBinds    :: RdrNameHsBinds -> RnM_Fixes s RenamedHsBinds
-rnMethodBinds :: RnName{-class-} -> RdrNameMonoBinds -> RnM_Fixes s RenamedMonoBinds
-rnBinds              :: RdrNameHsBinds -> RnM_Fixes s (RenamedHsBinds, FreeVars, [RnName])
+%************************************************************************
+%*                                                                     *
+\subsubsection{ Top-level bindings}
+%*                                                                     *
+%************************************************************************

 
 

-rnTopBinds EmptyBinds                     = returnRn EmptyBinds
-rnTopBinds (SingleBind (RecBind bind))    = rnTopMonoBinds bind []
-rnTopBinds (BindWith (RecBind bind) sigs) = rnTopMonoBinds bind sigs
-  -- the parser doesn't produce other forms
+@rnTopBinds@ assumes that the environment already
+contains bindings for the binders of this particular binding.

 
 

--- ********************************************************************
+\begin{code}
+rnTopBinds    :: RdrNameHsBinds -> RnMS (RenamedHsBinds, FreeVars)

 
 

-rnMethodBinds class_name EmptyMonoBinds = returnRn EmptyMonoBinds
+rnTopBinds EmptyBinds                    = returnRn (EmptyBinds, emptyFVs)
+rnTopBinds (MonoBind bind sigs _)        = rnTopMonoBinds bind sigs
+  -- The parser doesn't produce other forms

 
 

-rnMethodBinds class_name (AndMonoBinds mb1 mb2)
-  = andRn AndMonoBinds (rnMethodBinds class_name mb1)
-                      (rnMethodBinds class_name mb2)

 
 

-rnMethodBinds class_name (FunMonoBind occname inf matches locn)
-  = pushSrcLocRn locn                             $
-    lookupClassOp class_name occname              `thenRn` \ op_name ->
-    mapAndUnzipRn rnMatch matches                 `thenRn` \ (new_matches, _) ->
-    mapRn (checkPrecMatch inf op_name) new_matches `thenRn_`
-    returnRn (FunMonoBind op_name inf new_matches locn)
+rnTopMonoBinds EmptyMonoBinds sigs 
+  = returnRn (EmptyBinds, emptyFVs)

 
 

-rnMethodBinds class_name (PatMonoBind (VarPatIn occname) grhss_and_binds locn)
-  = pushSrcLocRn locn                  $
-    lookupClassOp class_name occname   `thenRn` \ op_name ->
-    rnGRHSsAndBinds grhss_and_binds    `thenRn` \ (grhss_and_binds', _) ->
-    returnRn (PatMonoBind (VarPatIn op_name) grhss_and_binds' locn)
+rnTopMonoBinds mbinds sigs
+ =  mapRn lookupBndrRn binder_rdr_names        `thenRn` \ binder_names ->
+    let
+       binder_set    = mkNameSet binder_names
+       binder_occ_fm = listToFM [(nameOccName x,x) | x <- binder_names]
+    in
+    renameSigs opt_WarnMissingSigs binder_set
+              (lookupSigOccRn binder_occ_fm) sigs `thenRn` \ (siglist, sig_fvs) ->
+    rn_mono_binds siglist mbinds                  `thenRn` \ (final_binds, bind_fvs) ->
+    returnRn (final_binds, bind_fvs `plusFV` sig_fvs)
+  where
+    binder_rdr_names = map fst (bagToList (collectMonoBinders mbinds))
+
+-- the names appearing in the sigs have to be bound by 
+-- this group's binders.
+lookupSigOccRn binder_occ_fm rdr_name
+  = case lookupFM binder_occ_fm (rdrNameOcc rdr_name) of
+       Nothing -> failWithRn (mkUnboundName rdr_name)
+                             (unknownNameErr rdr_name)
+       Just x  -> returnRn x
+\end{code}

 
 

--- Can't handle method pattern-bindings which bind multiple methods.
-rnMethodBinds _ mbind@(PatMonoBind other_pat _ locn)
-  = failButContinueRn EmptyMonoBinds (methodBindErr mbind locn)
+%************************************************************************
+%*                                                                     *
+%*             Nested binds
+%*                                                                     *
+%************************************************************************
+
+\subsubsection{Nested binds}

 
 

--- ********************************************************************
+@rnMonoBinds@
+\begin{itemize}
+\item collects up the binders for this declaration group,
+\item checks that they form a set
+\item extends the environment to bind them to new local names
+\item calls @rnMonoBinds@ to do the real work
+\end{itemize}
+%
+\begin{code}
+rnBinds              :: RdrNameHsBinds 
+             -> (RenamedHsBinds -> RnMS (result, FreeVars))
+             -> RnMS (result, FreeVars)

 
 

-rnBinds EmptyBinds                     = returnRn (EmptyBinds,emptyUniqSet,[])
-rnBinds (SingleBind (RecBind bind))    = rnNestedMonoBinds bind []
-rnBinds (BindWith (RecBind bind) sigs) = rnNestedMonoBinds bind sigs
+rnBinds EmptyBinds            thing_inside = thing_inside EmptyBinds
+rnBinds (MonoBind bind sigs _) thing_inside = rnMonoBinds bind sigs thing_inside

   -- the parser doesn't produce other forms
   -- the parser doesn't produce other forms

-\end{code}

 
 

-@rnNestedMonoBinds@
-       - collects up the binders for this declaration group,
-       - checkes that they form a set
-       - extends the environment to bind them to new local names
-       - calls @rnMonoBinds@ to do the real work

 
 

-In contrast, @rnTopMonoBinds@ doesn't extend the environment, because that's
-already done in pass3. All it does is call @rnMonoBinds@ and discards
-the free var info.
+rnMonoBinds :: RdrNameMonoBinds 
+            -> [RdrNameSig]
+           -> (RenamedHsBinds -> RnMS (result, FreeVars))
+           -> RnMS (result, FreeVars)

 
 

-\begin{code}
-rnTopMonoBinds :: RdrNameMonoBinds -> [RdrNameSig] -> RnM_Fixes s RenamedHsBinds
+rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds

 
 

-rnTopMonoBinds EmptyMonoBinds sigs = returnRn EmptyBinds
+rnMonoBinds mbinds sigs        thing_inside -- Non-empty monobinds
+  =    -- Extract all the binders in this group,
+       -- and extend current scope, inventing new names for the new binders
+       -- This also checks that the names form a set
+    bindLocatedLocalsRn (text "a binding group") mbinders_w_srclocs
+    $ \ new_mbinders ->
+    let
+       binder_set  = mkNameSet new_mbinders

 
 

-rnTopMonoBinds mbs sigs
- = rnBindSigs True{-top-level-} (collectMonoBinders mbs) sigs `thenRn` \ siglist ->
-   rnMonoBinds mbs siglist `thenRn` \ (new_binds, fv_set) ->
-   returnRn new_binds
+          -- Weed out the fixity declarations that do not
+          -- apply to any of the binders in this group.
+       (sigs_for_me, fixes_not_for_me) = partition forLocalBind sigs

 
 

+       forLocalBind (FixSig sig@(FixitySig name _ _ )) =
+           isJust (lookupFM binder_occ_fm (rdrNameOcc name))
+       forLocalBind _ = True

 
 

-rnNestedMonoBinds :: RdrNameMonoBinds -> [RdrNameSig]
-                 -> RnM_Fixes s (RenamedHsBinds, FreeVars, [RnName])
+       binder_occ_fm = listToFM [(nameOccName x,x) | x <- new_mbinders]

 
 

-rnNestedMonoBinds EmptyMonoBinds sigs
-  = returnRn (EmptyBinds, emptyUniqSet, [])
+    in
+       -- Report the fixity declarations in this group that 
+       -- don't refer to any of the group's binders.
+       --
+    mapRn_ (unknownSigErr) fixes_not_for_me     `thenRn_`
+    renameSigs False binder_set
+              (lookupSigOccRn binder_occ_fm) sigs_for_me   `thenRn` \ (siglist, sig_fvs) ->
+    let
+       fixity_sigs = [(name,sig) | FixSig sig@(FixitySig name _ _) <- siglist ]
+    in
+       -- Install the fixity declarations that do apply here and go.
+    extendFixityEnv fixity_sigs (
+      rn_mono_binds siglist mbinds
+    )                                     `thenRn` \ (binds, bind_fvs) ->

 
 

-rnNestedMonoBinds mbinds sigs  -- Non-empty monobinds
-  =
-       -- Extract all the binders in this group,
-       -- and extend current scope, inventing new names for the new binders
-       -- This also checks that the names form a set
+    -- Now do the "thing inside", and deal with the free-variable calculations
+    thing_inside binds                    `thenRn` \ (result,result_fvs) ->

     let
     let

-       mbinders_w_srclocs = collectMonoBindersAndLocs mbinds
-       mbinders           = map fst mbinders_w_srclocs
+       all_fvs        = result_fvs `plusFV` bind_fvs `plusFV` sig_fvs
+       unused_binders = nameSetToList (binder_set `minusNameSet` all_fvs)

     in
     in

-    newLocalNames "variable"
-                 mbinders_w_srclocs    `thenRn` \ new_mbinders ->
-
-    extendSS2 new_mbinders (
-        rnBindSigs False{-not top- level-} mbinders sigs `thenRn` \ siglist ->
-        rnMonoBinds mbinds  siglist
-    )                                  `thenRn` \ (new_binds, fv_set) ->
-    returnRn (new_binds, fv_set, new_mbinders)
+    warnUnusedLocalBinds unused_binders        `thenRn_`
+    returnRn (result, delListFromNameSet all_fvs new_mbinders)
+  where
+    mbinders_w_srclocs = bagToList (collectMonoBinders mbinds)

 \end{code}
 
 \end{code}
 

-@rnMonoBinds@ is used by *both* top-level and nested bindings.  It
-assumes that all variables bound in this group are already in scope.
-This is done *either* by pass 3 (for the top-level bindings),
-*or* by @rnNestedMonoBinds@ (for the nested ones).
+
+%************************************************************************
+%*                                                                     *
+\subsubsection{                MonoBinds -- the main work is done here}
+%*                                                                     *
+%************************************************************************
+
+@rn_mono_binds@ is used by {\em both} top-level and nested bindings.
+It assumes that all variables bound in this group are already in scope.
+This is done {\em either} by pass 3 (for the top-level bindings),
+{\em or} by @rnMonoBinds@ (for the nested ones).

 
 \begin{code}
 
 \begin{code}

-rnMonoBinds :: RdrNameMonoBinds
-           -> [RenamedSig]     -- Signatures attached to this group
-           -> RnM_Fixes s (RenamedHsBinds, FreeVars)
+rn_mono_binds :: [RenamedSig]          -- Signatures attached to this group
+             -> RdrNameMonoBinds       
+             -> RnMS (RenamedHsBinds,  -- 
+                        FreeVars)      -- Free variables

 
 

-rnMonoBinds mbinds siglist
+rn_mono_binds siglist mbinds

   =
         -- Rename the bindings, returning a MonoBindsInfo
         -- which is a list of indivisible vertices so far as
         -- the strongly-connected-components (SCC) analysis is concerned
   =
         -- Rename the bindings, returning a MonoBindsInfo
         -- which is a list of indivisible vertices so far as
         -- the strongly-connected-components (SCC) analysis is concerned

-    flattenMonoBinds 0 siglist mbinds  `thenRn` \ (_, mbinds_info) ->
+    flattenMonoBinds siglist mbinds            `thenRn` \ mbinds_info ->

 
         -- Do the SCC analysis
 
         -- Do the SCC analysis

-    let vertices = mkVertices mbinds_info
-       edges   = mkEdges     mbinds_info
-
-       scc_result = stronglyConnComp (==) edges vertices
+    let 
+        edges      = mkEdges (mbinds_info `zip` [(0::Int)..])
+       scc_result  = stronglyConnComp edges
+       final_binds = foldr1 ThenBinds (map reconstructCycle scc_result)

 
         -- Deal with bound and free-var calculation
 
         -- Deal with bound and free-var calculation

-       rhs_free_vars = foldr f emptyUniqSet mbinds_info
-
-       final_binds = reconstructRec scc_result edges mbinds_info
-
-       happy_answer = returnRn (final_binds, rhs_free_vars)
+       rhs_fvs = plusFVs [fvs | (_,fvs,_,_) <- mbinds_info]

     in
     in

-    case (inline_sigs_in_recursive_binds final_binds) of
-      Nothing -> happy_answer
-      Just names_n_locns ->
--- SLPJ: sometimes want recursive INLINE for worker wrapper style stuff
---     addErrRn (inlineInRecursiveBindsErr names_n_locns) `thenRn_`
-       {-not so-}happy_answer
-  where
-    f :: (a,b, FreeVars, c,d) -> FreeVars -> FreeVars
-
-    f (_, _, fvs_body, _, _) fvs_sofar = fvs_sofar `unionUniqSets` fvs_body
-
-    inline_sigs_in_recursive_binds (BindWith (RecBind _) sigs)
-      = case [(n, locn) | (InlineSig n locn) <- sigs ] of
-         []   -> Nothing
-         sigh ->
-#if OMIT_DEFORESTER
-               Just sigh
-#else
-               -- Allow INLINEd recursive functions if they are
-               -- designated DEFORESTable too.
-               case [(n, locn) | (DeforestSig n locn) <- sigs ] of
-                       []   -> Just sigh
-                       sigh -> Nothing
-#endif
-
-    inline_sigs_in_recursive_binds (ThenBinds b1 b2)
-      = case (inline_sigs_in_recursive_binds b1) of
-         Nothing -> inline_sigs_in_recursive_binds b2
-         Just  x -> Just x -- NB: won't report error(s) in b2
-
-    inline_sigs_in_recursive_binds anything_else = Nothing
+    returnRn (final_binds, rhs_fvs)

 \end{code}
 
 @flattenMonoBinds@ is ever-so-slightly magical in that it sticks
 unique ``vertex tags'' on its output; minor plumbing required.
 
 \end{code}
 
 @flattenMonoBinds@ is ever-so-slightly magical in that it sticks
 unique ``vertex tags'' on its output; minor plumbing required.
 

+Sigh --- need to pass along the signatures for the group of bindings,
+in case any of them \fbox{\ ???\ } 
+

 \begin{code}
 \begin{code}

-flattenMonoBinds :: Int                                -- Next free vertex tag
-                -> [RenamedSig]                -- Signatures
+flattenMonoBinds :: [RenamedSig]               -- Signatures

                 -> RdrNameMonoBinds
                 -> RdrNameMonoBinds

-                -> RnM_Fixes s (Int, FlatMonoBindsInfo)
+                -> RnMS [FlatMonoBindsInfo]

 
 

-flattenMonoBinds uniq sigs EmptyMonoBinds = returnRn (uniq, [])
+flattenMonoBinds sigs EmptyMonoBinds = returnRn []

 
 

-flattenMonoBinds uniq sigs (AndMonoBinds bs1 bs2)
-  = flattenMonoBinds uniq  sigs bs1    `thenRn` \ (uniq1, flat1) ->
-    flattenMonoBinds uniq1 sigs bs2    `thenRn` \ (uniq2, flat2) ->
-    returnRn (uniq2, flat1 ++ flat2)
+flattenMonoBinds sigs (AndMonoBinds bs1 bs2)
+  = flattenMonoBinds sigs bs1  `thenRn` \ flat1 ->
+    flattenMonoBinds sigs bs2  `thenRn` \ flat2 ->
+    returnRn (flat1 ++ flat2)

 
 

-flattenMonoBinds uniq sigs (PatMonoBind pat grhss_and_binds locn)
+flattenMonoBinds sigs (PatMonoBind pat grhss locn)

   = pushSrcLocRn locn                  $
   = pushSrcLocRn locn                  $

-    rnPat pat                          `thenRn` \ pat' ->
-    rnGRHSsAndBinds grhss_and_binds    `thenRn` \ (grhss_and_binds', fvs) ->
+    rnPat pat                          `thenRn` \ (pat', pat_fvs) ->

 
         -- Find which things are bound in this group
     let
 
         -- Find which things are bound in this group
     let

-       names_bound_here = collectPatBinders pat'
-
-       sigs_etc_for_here = foldl (sig_for_here (\ n -> n `is_elem` names_bound_here))
-                                 [] sigs
-
-       sigs_fvs = foldr sig_fv emptyUniqSet sigs_etc_for_here
-
-       is_elem = isIn "flattenMonoBinds"
+       names_bound_here = mkNameSet (collectPatBinders pat')
+       sigs_for_me      = sigsForMe (`elemNameSet` names_bound_here) sigs

     in
     in

-    returnRn (
-       uniq + 1,
-       [(uniq,
-         mkUniqSet names_bound_here,
-          fvs `unionUniqSets` sigs_fvs,
-          PatMonoBind pat' grhss_and_binds' locn,
-          sigs_etc_for_here
+    rnGRHSs grhss                      `thenRn` \ (grhss', fvs) ->
+    returnRn 
+       [(names_bound_here,
+         fvs `plusFV` pat_fvs,
+         PatMonoBind pat' grhss' locn,
+         sigs_for_me

         )]
         )]

-    )

 
 

-flattenMonoBinds uniq sigs (FunMonoBind name inf matches locn)
-  = pushSrcLocRn locn                           $
-    lookupValue name                            `thenRn` \ name' ->
-    mapAndUnzipRn rnMatch matches               `thenRn` \ (new_matches, fv_lists) ->
-    mapRn (checkPrecMatch inf name') new_matches `thenRn_`
+flattenMonoBinds sigs (FunMonoBind name inf matches locn)
+  = pushSrcLocRn locn                                  $
+    lookupBndrRn name                                  `thenRn` \ new_name ->

     let
     let

-       fvs = unionManyUniqSets fv_lists
-
-       sigs_for_me = foldl (sig_for_here (\ n -> n == name')) [] sigs
-
-       sigs_fvs = foldr sig_fv emptyUniqSet sigs_for_me
+       sigs_for_me = sigsForMe (new_name ==) sigs

     in
     in

-    returnRn (
-      uniq + 1,
-      [(uniq,
-       unitUniqSet name',
-       fvs `unionUniqSets` sigs_fvs,
-       FunMonoBind name' inf new_matches locn,
+    mapFvRn rnMatch matches                            `thenRn` \ (new_matches, fvs) ->
+    mapRn_ (checkPrecMatch inf new_name) new_matches   `thenRn_`
+    returnRn
+      [(unitNameSet new_name,
+       fvs,
+       FunMonoBind new_name inf new_matches locn,

        sigs_for_me
        )]
        sigs_for_me
        )]

-    )

 \end{code}
 
 \end{code}
 

-Grab type-signatures/user-pragmas of interest:
+
+@rnMethodBinds@ is used for the method bindings of a class and an instance
+declaration.   Like @rnMonoBinds@ but without dependency analysis.
+
+NOTA BENE: we record each {\em binder} of a method-bind group as a free variable.
+That's crucial when dealing with an instance decl:
+\begin{verbatim}
+       instance Foo (T a) where
+          op x = ...
+\end{verbatim}
+This might be the {\em sole} occurrence of @op@ for an imported class @Foo@,
+and unless @op@ occurs we won't treat the type signature of @op@ in the class
+decl for @Foo@ as a source of instance-decl gates.  But we should!  Indeed,
+in many ways the @op@ in an instance decl is just like an occurrence, not
+a binder.
+

 \begin{code}
 \begin{code}

-sig_for_here want_me acc s@(Sig n _ _ _)     | want_me n = s:acc
-sig_for_here want_me acc s@(InlineSig n _)   | want_me n = s:acc
-sig_for_here want_me acc s@(DeforestSig n _) | want_me n = s:acc
-sig_for_here want_me acc s@(SpecSig n _ _ _) | want_me n = s:acc
-sig_for_here want_me acc s@(MagicUnfoldingSig n _ _)
-                                            | want_me n = s:acc
-sig_for_here want_me acc other_wise                     = acc
-
--- If a SPECIALIZE pragma is of the "... = blah" form,
--- then we'd better make sure "blah" is taken into
--- acct in the dependency analysis (or we get an
--- unexpected out-of-scope error)! WDP 95/07
-
-sig_fv (SpecSig _ _ (Just blah) _) acc = acc `unionUniqSets` unitUniqSet blah
-sig_fv _                          acc = acc
+rnMethodBinds :: RdrNameMonoBinds -> RnMS (RenamedMonoBinds, FreeVars)
+
+rnMethodBinds EmptyMonoBinds = returnRn (EmptyMonoBinds, emptyFVs)
+
+rnMethodBinds (AndMonoBinds mb1 mb2)
+  = rnMethodBinds mb1  `thenRn` \ (mb1', fvs1) ->
+    rnMethodBinds mb2  `thenRn` \ (mb2', fvs2) ->
+    returnRn (mb1' `AndMonoBinds` mb2', fvs1 `plusFV` fvs2)
+
+rnMethodBinds (FunMonoBind name inf matches locn)
+  = pushSrcLocRn locn                                  $
+
+    lookupGlobalOccRn name                             `thenRn` \ sel_name -> 
+       -- We use the selector name as the binder
+
+    mapFvRn rnMatch matches                            `thenRn` \ (new_matches, fvs) ->
+    mapRn_ (checkPrecMatch inf sel_name) new_matches   `thenRn_`
+    returnRn (FunMonoBind sel_name inf new_matches locn, fvs `addOneFV` sel_name)
+
+rnMethodBinds (PatMonoBind (VarPatIn name) grhss locn)
+  = pushSrcLocRn locn                  $
+    lookupGlobalOccRn name             `thenRn` \ sel_name -> 
+    rnGRHSs grhss                      `thenRn` \ (grhss', fvs) ->
+    returnRn (PatMonoBind (VarPatIn sel_name) grhss' locn, fvs `addOneFV` sel_name)
+
+-- Can't handle method pattern-bindings which bind multiple methods.
+rnMethodBinds mbind@(PatMonoBind other_pat _ locn)
+  = pushSrcLocRn locn  $
+    failWithRn (EmptyMonoBinds, emptyFVs) (methodBindErr mbind)

 \end{code}
 
 \end{code}
 

+

 %************************************************************************
 %*                                                                     *
 \subsection[reconstruct-deps]{Reconstructing dependencies}
 %************************************************************************
 %*                                                                     *
 \subsection[reconstruct-deps]{Reconstructing dependencies}

@@ -400,60 +419,22 @@ This @MonoBinds@- and @ClassDecls@-specific code is segregated here,
 as the two cases are similar.
 
 \begin{code}
 as the two cases are similar.
 
 \begin{code}

-reconstructRec :: [Cycle]      -- Result of SCC analysis; at least one
-               -> [Edge]       -- Original edges
-               -> FlatMonoBindsInfo
-               -> RenamedHsBinds
+reconstructCycle :: SCC FlatMonoBindsInfo
+                -> RenamedHsBinds
+
+reconstructCycle (AcyclicSCC (_, _, binds, sigs))
+  = MonoBind binds sigs NonRecursive

 
 

-reconstructRec cycles edges mbi
-  = foldr1 ThenBinds (map (reconstructCycle mbi) cycles)
+reconstructCycle (CyclicSCC cycle)
+  = MonoBind this_gp_binds this_gp_sigs Recursive

   where
   where

-    reconstructCycle :: FlatMonoBindsInfo -> Cycle -> RenamedHsBinds
-
-    reconstructCycle mbi2 cycle
-      = case [(binds,sigs) | (vertex, _, _, binds, sigs) <- mbi2, vertex `is_elem` cycle]
-                 of { relevant_binds_and_sigs ->
-
-       case (unzip relevant_binds_and_sigs) of { (binds, sig_lists) ->
-
-       case (foldr AndMonoBinds EmptyMonoBinds binds) of { this_gp_binds ->
-       let
-           this_gp_sigs        = foldr1 (++) sig_lists
-           have_sigs           = not (null sig_lists)
-               -- ToDo: this might not be the right
-               -- thing to call this predicate;
-               -- e.g. "have_sigs [[], [], []]" ???????????
-       in
-       mk_binds this_gp_binds this_gp_sigs (isCyclic edges cycle) have_sigs
-       }}}
-      where
-       is_elem = isIn "reconstructRec"
-
-       mk_binds :: RenamedMonoBinds -> [RenamedSig]
-                -> Bool -> Bool -> RenamedHsBinds
-
-       mk_binds bs ss True  False              = SingleBind (RecBind    bs)
-       mk_binds bs ss True  True{-have sigs-}  = BindWith   (RecBind    bs) ss
-       mk_binds bs ss False False              = SingleBind (NonRecBind bs)
-       mk_binds bs ss False True{-have sigs-}  = BindWith   (NonRecBind bs) ss
-
-       -- moved from Digraph, as this is the only use here
-       -- (avoid overloading cost).  We have to use elem
-       -- (not FiniteMaps or whatever), because there may be
-       -- many edges out of one vertex.  We give it its own
-       -- "elem" just for speed.
-
-       isCyclic es []  = panic "isCyclic: empty component"
-       isCyclic es [v] = (v,v) `elem` es
-       isCyclic es vs  = True
-
-       elem _ []       = False
-       elem x (y:ys)   = x==y || elem x ys
+    this_gp_binds      = foldr1 AndMonoBinds [binds | (_, _, binds, _) <- cycle]
+    this_gp_sigs       = foldr1 (++)        [sigs  | (_, _, _, sigs) <- cycle]

 \end{code}
 
 %************************************************************************
 %*                                                                     *
 \end{code}
 
 %************************************************************************
 %*                                                                     *

-%*     Manipulating FlatMonoBindInfo                                   *
+\subsubsection{        Manipulating FlatMonoBindInfo}

 %*                                                                     *
 %************************************************************************
 
 %*                                                                     *
 %************************************************************************
 

@@ -464,36 +445,24 @@ renamed.
 
 \begin{code}
 type FlatMonoBindsInfo
 
 \begin{code}
 type FlatMonoBindsInfo

-  = [(VertexTag,               -- Identifies the vertex
-      UniqSet RnName,          -- Set of names defined in this vertex
-      UniqSet RnName,          -- Set of names used in this vertex
-      RenamedMonoBinds,                -- Binding for this vertex (always just one binding, either fun or pat)
-      [RenamedSig])            -- Signatures, if any, for this vertex
-    ]
-
-mkVertices :: FlatMonoBindsInfo -> [VertexTag]
-mkEdges    :: FlatMonoBindsInfo -> [Edge]
+  = (NameSet,                  -- Set of names defined in this vertex
+     NameSet,                  -- Set of names used in this vertex
+     RenamedMonoBinds,
+     [RenamedSig])             -- Signatures, if any, for this vertex

 
 

-mkVertices info = [ vertex | (vertex,_,_,_,_) <- info]
+mkEdges :: [(FlatMonoBindsInfo, VertexTag)] -> [(FlatMonoBindsInfo, VertexTag, [VertexTag])]

 
 mkEdges flat_info
 
 mkEdges flat_info

- -- An edge (v,v') indicates that v depends on v'
-  = -- pprTrace "mkEdges:" (ppAboves [ppAboves[ppInt v, ppCat [ppr PprDebug d|d <- uniqSetToList defd], ppCat [ppr PprDebug u|u <- uniqSetToList used]] | (v,defd,used,_,_) <- flat_info]) $
-    [ (source_vertex, target_vertex)
-    | (source_vertex, _, used_names, _, _) <- flat_info,
-      target_name   <- uniqSetToList used_names,
-      target_vertex <- vertices_defining target_name flat_info
+  = [ (info, tag, dest_vertices (nameSetToList names_used))
+    | (info@(names_defined, names_used, mbind, sigs), tag) <- flat_info

     ]
     ]

-    where
-    -- If each name only has one binding in this group, then
-    -- vertices_defining will always return the empty list, or a
-    -- singleton.  The case when there is more than one binding (an
-    -- error) needs more thought.
-
-    vertices_defining name flat_info2
-     = [ vertex |  (vertex, names_defined, _, _, _) <- flat_info2,
-                name `elementOfUniqSet` names_defined
-       ]
+  where
+        -- An edge (v,v') indicates that v depends on v'
+    dest_vertices src_mentions = [ target_vertex
+                                | ((names_defined, _, _, _), target_vertex) <- flat_info,
+                                  mentioned_name <- src_mentions,
+                                  mentioned_name `elemNameSet` names_defined
+                                ]

 \end{code}
 
 
 \end{code}
 
 

@@ -503,141 +472,110 @@ mkEdges flat_info
 %*                                                                     *
 %************************************************************************
 
 %*                                                                     *
 %************************************************************************
 

-@rnBindSigs@ checks for: (a)~more than one sig for one thing;
-(b)~signatures given for things not bound here; (c)~with suitably
-flaggery, that all top-level things have type signatures.
+@renameSigs@ checks for:
+\begin{enumerate}
+\item more than one sig for one thing;
+\item signatures given for things not bound here;
+\item with suitably flaggery, that all top-level things have type signatures.
+\end{enumerate}
+%
+At the moment we don't gather free-var info from the types in
+signatures.  We'd only need this if we wanted to report unused tyvars.

 
 \begin{code}
 
 \begin{code}

-rnBindSigs :: Bool                     -- True <=> top-level binders
-           -> [RdrName]                -- Binders for this decl group
+renameSigs ::  Bool            -- True => warn if (required) type signatures are missing.
+           -> NameSet          -- Set of names bound in this group
+           -> (RdrName -> RnMS Name)

            -> [RdrNameSig]
            -> [RdrNameSig]

-           -> RnM_Fixes s [RenamedSig] -- List of Sig constructors
+           -> RnMS ([RenamedSig], FreeVars)     -- List of Sig constructors

 
 

-rnBindSigs is_toplev binder_occnames sigs
-  =
-        -- Rename the signatures
-        -- Will complain about sigs for variables not in this group
-    mapRn rename_sig sigs      `thenRn` \ sigs_maybe ->
-    let
-       sigs' = catMaybes sigs_maybe
-
-        -- Discard unbound ones we've already complained about, so we
-        -- complain about duplicate ones.
+renameSigs sigs_required binders lookup_occ_nm sigs
+  =     -- Rename the signatures
+    mapFvRn (renameSig lookup_occ_nm) sigs     `thenRn` \ (sigs', fvs) ->

 
 

-       (goodies, dups) = removeDups compare (filter not_unbound sigs')
+       -- Check for (a) duplicate signatures
+       --           (b) signatures for things not in this group
+       --           (c) optionally, bindings with no signature
+    let
+       (goodies, dups) = removeDups cmp_sig (sigsForMe (not . isUnboundName) sigs')
+       not_this_group  = sigsForMe (not . (`elemNameSet` binders)) goodies
+       type_sig_vars   = [n | Sig n _ _     <- goodies]
+       un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars
+                       | otherwise     = []

     in
     in

-    mapRn (addErrRn . dupSigDeclErr) dups `thenRn_`
-
-    getSrcLocRn                        `thenRn` \ locn ->
+    mapRn_ dupSigDeclErr dups                          `thenRn_`
+    mapRn_ unknownSigErr not_this_group                        `thenRn_`
+    mapRn_ (addWarnRn.missingSigWarn) un_sigd_binders  `thenRn_`
+    returnRn (sigs', fvs)      
+               -- bad ones and all:
+               -- we need bindings of *some* sort for every name
+
+-- We use lookupOccRn in the signatures, which is a little bit unsatisfactory
+-- because this won't work for:
+--     instance Foo T where
+--       {-# INLINE op #-}
+--       Baz.op = ...
+-- We'll just rename the INLINE prag to refer to whatever other 'op'
+-- is in scope.  (I'm assuming that Baz.op isn't in scope unqualified.)
+-- Doesn't seem worth much trouble to sort this.
+
+renameSig lookup_occ_nm (Sig v ty src_loc)
+  = pushSrcLocRn src_loc $
+    lookup_occ_nm v                            `thenRn` \ new_v ->
+    rnHsSigType (quotes (ppr v)) ty            `thenRn` \ (new_ty,fvs) ->
+    returnRn (Sig new_v new_ty src_loc, fvs `addOneFV` new_v)
+
+renameSig _ (SpecInstSig ty src_loc)
+  = pushSrcLocRn src_loc $
+    rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ (new_ty, fvs) ->
+    returnRn (SpecInstSig new_ty src_loc, fvs)
+
+renameSig lookup_occ_nm (SpecSig v ty src_loc)
+  = pushSrcLocRn src_loc $
+    lookup_occ_nm v                    `thenRn` \ new_v ->
+    rnHsSigType (quotes (ppr v)) ty    `thenRn` \ (new_ty,fvs) ->
+    returnRn (SpecSig new_v new_ty src_loc, fvs `addOneFV` new_v)
+
+renameSig lookup_occ_nm (FixSig (FixitySig v fix src_loc))
+  = pushSrcLocRn src_loc $
+    lookup_occ_nm v            `thenRn` \ new_v ->
+    returnRn (FixSig (FixitySig new_v fix src_loc), unitFV new_v)
+
+renameSig lookup_occ_nm (InlineSig v p src_loc)
+  = pushSrcLocRn src_loc $
+    lookup_occ_nm v            `thenRn` \ new_v ->
+    returnRn (InlineSig new_v p src_loc, unitFV new_v)
+
+renameSig lookup_occ_nm (NoInlineSig v p src_loc)
+  = pushSrcLocRn src_loc $
+    lookup_occ_nm v            `thenRn` \ new_v ->
+    returnRn (NoInlineSig new_v p src_loc, unitFV new_v)
+\end{code}

 
 

-    (if (is_toplev && opt_SigsRequired) then
-       let
-           sig_frees = catMaybes (map (sig_free sigs) binder_occnames)
-       in
-       mapRn (addErrRn . missingSigErr locn) sig_frees
-     else
-       returnRn []
-    )                          `thenRn_`
+Checking for distinct signatures; oh, so boring

 
 

-    returnRn sigs' -- bad ones and all:
-                  -- we need bindings of *some* sort for every name
-  where
-    rename_sig (Sig v ty pragmas src_loc)
-      = pushSrcLocRn src_loc $
-       if not (v `elem` binder_occnames) then
-          addErrRn (unknownSigDeclErr "type signature" v src_loc) `thenRn_`
-          returnRn Nothing
-       else
-          lookupValue v                        `thenRn` \ new_v ->
-          rnPolyType nullTyVarNamesEnv ty      `thenRn` \ new_ty ->
-
-          ASSERT(isNoGenPragmas pragmas)
-          returnRn (Just (Sig new_v new_ty noGenPragmas src_loc))
-
-    -- and now, the various flavours of value-modifying user-pragmas:
-
-    rename_sig (SpecSig v ty using src_loc)
-      = pushSrcLocRn src_loc $
-       if not (v `elem` binder_occnames) then
-          addErrRn (unknownSigDeclErr "SPECIALIZE pragma" v src_loc) `thenRn_`
-          returnRn Nothing
-       else
-          lookupValue v                        `thenRn` \ new_v ->
-          rnPolyType nullTyVarNamesEnv ty      `thenRn` \ new_ty ->
-          rn_using using                       `thenRn` \ new_using ->
-          returnRn (Just (SpecSig new_v new_ty new_using src_loc))
-      where
-       rn_using Nothing  = returnRn Nothing
-       rn_using (Just x) = lookupValue x `thenRn` \ new_x ->
-                           returnRn (Just new_x)
-
-    rename_sig (InlineSig v src_loc)
-      = pushSrcLocRn src_loc $
-       if not (v `elem` binder_occnames) then
-          addErrRn (unknownSigDeclErr "INLINE pragma" v src_loc) `thenRn_`
-          returnRn Nothing
-       else
-          lookupValue v        `thenRn` \ new_v ->
-          returnRn (Just (InlineSig new_v src_loc))
-
-    rename_sig (DeforestSig v src_loc)
-      = pushSrcLocRn src_loc $
-       if not (v `elem` binder_occnames) then
-          addErrRn (unknownSigDeclErr "DEFOREST pragma" v src_loc) `thenRn_`
-          returnRn Nothing
-       else
-          lookupValue v        `thenRn` \ new_v ->
-          returnRn (Just (DeforestSig new_v src_loc))
-
-    rename_sig (MagicUnfoldingSig v str src_loc)
-      = pushSrcLocRn src_loc $
-       if not (v `elem` binder_occnames) then
-          addErrRn (unknownSigDeclErr "MAGIC_UNFOLDING pragma" v src_loc) `thenRn_`
-          returnRn Nothing
-       else
-          lookupValue v        `thenRn` \ new_v ->
-          returnRn (Just (MagicUnfoldingSig new_v str src_loc))
-
-    not_unbound :: RenamedSig -> Bool
-
-    not_unbound (Sig n _ _ _)            = not (isRnUnbound n)
-    not_unbound (SpecSig n _ _ _)        = not (isRnUnbound n)
-    not_unbound (InlineSig n _)                  = not (isRnUnbound n)
-    not_unbound (DeforestSig n _)        = not (isRnUnbound n)
-    not_unbound (MagicUnfoldingSig n _ _) = not (isRnUnbound n)
-
-    -------------------------------------
-    sig_free :: [RdrNameSig] -> RdrName -> Maybe RdrName
-       -- Return "Just x" if "x" has no type signature in
-       -- sigs.  Nothing, otherwise.
-
-    sig_free [] ny = Just ny
-    sig_free (Sig nx _ _ _ : rest) ny
-      = if (nx == ny) then Nothing else sig_free rest ny
-    sig_free (_ : rest) ny = sig_free rest ny
-
-    -------------------------------------
-    compare :: RenamedSig -> RenamedSig -> TAG_
-    compare (Sig n1 _ _ _)            (Sig n2 _ _ _)             = n1 `cmp` n2
-    compare (InlineSig n1 _)          (InlineSig n2 _)           = n1 `cmp` n2
-    compare (MagicUnfoldingSig n1 _ _) (MagicUnfoldingSig n2 _ _) = n1 `cmp` n2
-    compare (SpecSig n1 ty1 _ _)       (SpecSig n2 ty2 _ _)
-      = -- may have many specialisations for one value;
-       -- but not ones that are exactly the same...
-       thenCmp (n1 `cmp` n2) (cmpPolyType cmp ty1 ty2)
-
-    compare other_1 other_2    -- tags *must* be different
-      = let tag1 = tag other_1
-           tag2 = tag other_2
-       in
-       if tag1 _LT_ tag2 then LT_ else GT_
-
-    tag (Sig n1 _ _ _)            = (ILIT(1) :: FAST_INT)
-    tag (SpecSig n1 _ _ _)        = ILIT(2)
-    tag (InlineSig n1 _)          = ILIT(3)
-    tag (MagicUnfoldingSig n1 _ _) = ILIT(4)
-    tag (DeforestSig n1 _)         = ILIT(5)
-    tag _ = panic# "tag(RnBinds)"
+\begin{code}
+cmp_sig :: RenamedSig -> RenamedSig -> Ordering
+cmp_sig (Sig n1 _ _)        (Sig n2 _ _)            = n1 `compare` n2
+cmp_sig (InlineSig n1 _ _)     (InlineSig n2 _ _)    = n1 `compare` n2
+cmp_sig (NoInlineSig n1 _ _)   (NoInlineSig n2 _ _)  = n1 `compare` n2
+cmp_sig (SpecInstSig ty1 _)  (SpecInstSig ty2 _)     = cmpHsType compare ty1 ty2
+cmp_sig (SpecSig n1 ty1 _)   (SpecSig n2 ty2 _) 
+  = -- may have many specialisations for one value;
+    -- but not ones that are exactly the same...
+       thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2)
+
+cmp_sig other_1 other_2                                        -- Tags *must* be different
+  | (sig_tag other_1) _LT_ (sig_tag other_2) = LT 
+  | otherwise                               = GT
+
+sig_tag (Sig n1 _ _)              = (ILIT(1) :: FAST_INT)
+sig_tag (SpecSig n1 _ _)          = ILIT(2)
+sig_tag (InlineSig n1 _ _)        = ILIT(3)
+sig_tag (NoInlineSig n1 _ _)      = ILIT(4)
+sig_tag (SpecInstSig _ _)         = ILIT(5)
+sig_tag (FixSig _)                = ILIT(6)
+sig_tag _                         = panic# "tag(RnBinds)"

 \end{code}
 
 %************************************************************************
 \end{code}
 
 %************************************************************************

@@ -647,46 +585,33 @@ rnBindSigs is_toplev binder_occnames sigs
 %************************************************************************
 
 \begin{code}
 %************************************************************************
 
 \begin{code}

-dupSigDeclErr sigs
-  = let
-       undup_sigs = fst (removeDups cmp_sig sigs)
-    in
-    addErrLoc locn1
-       ("more than one "++what_it_is++"\n\thas been given for these variables") ( \ sty ->
-    ppAboves (map (ppr sty) undup_sigs) )
+dupSigDeclErr (sig:sigs)
+  = pushSrcLocRn loc $
+    addErrRn (sep [ptext SLIT("Duplicate") <+> ptext what_it_is <> colon,
+                  ppr sig])
+  where
+    (what_it_is, loc) = sig_doc sig
+
+unknownSigErr sig
+  = pushSrcLocRn loc $
+    addErrRn (sep [ptext SLIT("Misplaced"),
+                  ptext what_it_is <> colon,
+                  ppr sig])

   where
   where

-    (what_it_is, locn1)
-      = case (head sigs) of
-         Sig        _ _ _ loc -> ("type signature",loc)
-         ClassOpSig _ _ _ loc -> ("class-method type signature", loc)
-         SpecSig    _ _ _ loc -> ("SPECIALIZE pragma",loc)
-         InlineSig  _     loc -> ("INLINE pragma",loc)
-         MagicUnfoldingSig _ _ loc -> ("MAGIC_UNFOLDING pragma",loc)
-
-    cmp_sig a b = get_name a `cmp` get_name b
-
-    get_name (Sig        n _ _ _) = n
-    get_name (ClassOpSig n _ _ _) = n
-    get_name (SpecSig    n _ _ _) = n
-    get_name (InlineSig  n     _) = n
-    get_name (MagicUnfoldingSig n _ _) = n
-
-------------------------
-methodBindErr mbind locn
- = addErrLoc locn "Can't handle multiple methods defined by one pattern binding"
-       (\ sty -> ppr sty mbind)
-
---------------------------
-missingSigErr locn var
-  = addShortErrLocLine locn ( \ sty ->
-    ppBesides [ppStr "a definition but no type signature for `",
-              ppr sty var,
-              ppStr "'."])
-
---------------------------------
-unknownSigDeclErr flavor var locn
-  = addShortErrLocLine locn ( \ sty ->
-    ppBesides [ppStr flavor, ppStr " but no definition for `",
-              ppr sty var,
-              ppStr "'."])
+    (what_it_is, loc) = sig_doc sig
+
+sig_doc (Sig        _ _ loc)        = (SLIT("type signature"),loc)
+sig_doc (ClassOpSig _ _ _ _ loc)     = (SLIT("class-method type signature"), loc)
+sig_doc (SpecSig    _ _ loc)        = (SLIT("SPECIALISE pragma"),loc)
+sig_doc (InlineSig  _ _    loc)             = (SLIT("INLINE pragma"),loc)
+sig_doc (NoInlineSig  _ _  loc)             = (SLIT("NOINLINE pragma"),loc)
+sig_doc (SpecInstSig _ loc)         = (SLIT("SPECIALISE instance pragma"),loc)
+sig_doc (FixSig (FixitySig _ _ loc)) = (SLIT("fixity declaration"), loc)
+
+missingSigWarn var
+  = sep [ptext SLIT("definition but no type signature for"), quotes (ppr var)]
+
+methodBindErr mbind
+ =  hang (ptext SLIT("Can't handle multiple methods defined by one pattern binding"))
+       4 (ppr mbind)

 \end{code}
 \end{code}