[project @ 1998-08-14 11:47:29 by sof]

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

diff --git a/ghc/compiler/rename/RnBinds.lhs b/ghc/compiler/rename/RnBinds.lhs
index 3c27d75..de84f39 100644 (file)
--- a/ghc/compiler/rename/RnBinds.lhs
+++ b/ghc/compiler/rename/RnBinds.lhs
@@ -9,36 +9,39 @@ 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,
-       rnBinds,
-       FreeVars(..),
-       DefinedVars(..)
+       rnTopBinds, rnTopMonoBinds,
+       rnMethodBinds, renameSigs,
+       rnBinds, rnMonoBinds

    ) where
 
    ) where
 

-import Ubiq
-import 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 RnExpr          ( rnMatch, rnGRHSsAndBinds, rnPat, checkPrecMatch )
 import RdrHsSyn
 import RnHsSyn
 import RnMonad
 import RnExpr          ( rnMatch, rnGRHSsAndBinds, rnPat, checkPrecMatch )

-
+import RnEnv           ( bindLocatedLocalsRn, lookupBndrRn, lookupOccRn, lookupGlobalOccRn,
+                         isUnboundName, warnUnusedBinds
+                       )

 import CmdLineOpts     ( opt_SigsRequired )
 import CmdLineOpts     ( opt_SigsRequired )

-import Digraph         ( stronglyConnComp )
-import ErrUtils                ( addErrLoc, addShortErrLocLine )
-import Name            ( RdrName )
-import Maybes          ( catMaybes )
-import Pretty
-import UniqSet         ( emptyUniqSet, unitUniqSet, mkUniqSet,
-                         unionUniqSets, unionManyUniqSets,
-                         elementOfUniqSet, uniqSetToList, UniqSet(..) )
-import Util            ( thenCmp, isIn, removeDups, panic, panic#, assertPanic )
+import Digraph         ( stronglyConnComp, SCC(..) )
+import Name            ( OccName(..), Provenance, 
+                         Name, isExportedName,
+                         NameSet, emptyNameSet, mkNameSet, unionNameSets, 
+                         minusNameSet, unionManyNameSets, elemNameSet, unitNameSet, nameSetToList
+                       )
+import BasicTypes      ( RecFlag(..), TopLevelFlag(..) )
+import Util            ( thenCmp, removeDups, panic, panic#, assertPanic )
+import UniqSet         ( UniqSet )
+import ListSetOps      ( minusList )
+import Bag             ( bagToList )
+import UniqFM          ( UniqFM )
+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

@@ -63,15 +66,6 @@ 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).

@@ -87,6 +81,7 @@ 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

@@ -113,6 +108,7 @@ 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

@@ -153,239 +149,227 @@ 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])
-
-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
-
--- ********************************************************************
-
-rnMethodBinds class_name EmptyMonoBinds = returnRn EmptyMonoBinds
+%************************************************************************
+%*                                                                     *
+%*             Top-level bindings
+%*                                                                     *
+%************************************************************************

 
 

-rnMethodBinds class_name (AndMonoBinds mb1 mb2)
-  = andRn AndMonoBinds (rnMethodBinds class_name mb1)
-                      (rnMethodBinds class_name mb2)
+@rnTopBinds@ assumes that the environment already
+contains bindings for the binders of this particular binding.

 
 

-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)
+\begin{code}
+rnTopBinds    :: RdrNameHsBinds -> RnMS s RenamedHsBinds

 
 

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

 
 

--- Can't handle method pattern-bindings which bind multiple methods.
-rnMethodBinds _ mbind@(PatMonoBind other_pat _ locn)
-  = failButContinueRn EmptyMonoBinds (methodBindErr mbind locn)

 
 

--- ********************************************************************
+rnTopMonoBinds EmptyMonoBinds sigs 
+  = returnRn EmptyBinds

 
 

-rnBinds EmptyBinds                     = returnRn (EmptyBinds,emptyUniqSet,[])
-rnBinds (SingleBind (RecBind bind))    = rnNestedMonoBinds bind []
-rnBinds (BindWith (RecBind bind) sigs) = rnNestedMonoBinds bind sigs
-  -- the parser doesn't produce other forms
+rnTopMonoBinds mbinds sigs
+ =  mapRn lookupBndrRn binder_rdr_names        `thenRn` \ binder_names ->
+    let
+       binder_set       = mkNameSet binder_names
+       exported_binders = mkNameSet (filter isExportedName binder_names)
+    in
+    rn_mono_binds TopLevel
+                 binder_set mbinds sigs                `thenRn` \ (new_binds, fv_set) ->
+    let
+       unused_binders = binder_set `minusNameSet` (fv_set `unionNameSets` exported_binders)
+    in
+    warnUnusedBinds unused_binders     `thenRn_`
+    returnRn new_binds
+  where
+    binder_rdr_names = map fst (bagToList (collectMonoBinders mbinds))

 \end{code}
 
 \end{code}
 

-@rnNestedMonoBinds@
+%************************************************************************
+%*                                                                     *
+%*             Nested binds
+%*                                                                     *
+%************************************************************************
+
+@rnMonoBinds@

        - collects up the binders for this declaration group,
        - collects up the binders for this declaration group,

-       - checkes that they form a set
+       - checks that they form a set

        - extends the environment to bind them to new local names
        - calls @rnMonoBinds@ to do the real work
 
        - 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.
-

 \begin{code}
 \begin{code}

-rnTopMonoBinds :: RdrNameMonoBinds -> [RdrNameSig] -> RnM_Fixes s RenamedHsBinds
-
-rnTopMonoBinds EmptyMonoBinds sigs = returnRn EmptyBinds
+rnBinds              :: RdrNameHsBinds 
+             -> (RenamedHsBinds -> RnMS s (result, FreeVars))
+             -> RnMS s (result, FreeVars)

 
 

-rnTopMonoBinds mbs sigs
- = rnBindSigs True{-top-level-} (collectMonoBinders mbs) sigs `thenRn` \ siglist ->
-   rnMonoBinds mbs siglist `thenRn` \ (new_binds, fv_set) ->
-   returnRn new_binds
+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

 
 
 
 

-rnNestedMonoBinds :: RdrNameMonoBinds -> [RdrNameSig]
-                 -> RnM_Fixes s (RenamedHsBinds, FreeVars, [RnName])
+rnMonoBinds :: RdrNameMonoBinds -> [RdrNameSig]
+           -> (RenamedHsBinds -> RnMS s (result, FreeVars))
+           -> RnMS s (result, FreeVars)

 
 

-rnNestedMonoBinds EmptyMonoBinds sigs
-  = returnRn (EmptyBinds, emptyUniqSet, [])
+rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds

 
 

-rnNestedMonoBinds mbinds sigs  -- Non-empty monobinds
-  =
-       -- Extract all the binders in this group,
+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
        -- and extend current scope, inventing new names for the new binders
        -- This also checks that the names form a set

+    bindLocatedLocalsRn (text "binding group") mbinders_w_srclocs              $ \ new_mbinders ->
+    let
+       binder_set = mkNameSet new_mbinders
+    in
+    rn_mono_binds NotTopLevel
+                 binder_set mbinds sigs        `thenRn` \ (binds,bind_fvs) ->
+
+       -- 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  `unionNameSets` bind_fvs
+       net_fvs        = all_fvs `minusNameSet` binder_set
+       unused_binders = 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)
+    warnUnusedBinds unused_binders     `thenRn_`
+    returnRn (result, net_fvs)
+  where
+    mbinders_w_srclocs = bagToList (collectMonoBinders mbinds)

 \end{code}
 
 \end{code}
 

+
+%************************************************************************
+%*                                                                     *
+%*             MonoBinds -- the main work is done here
+%*                                                                     *
+%************************************************************************
+

 @rnMonoBinds@ is used by *both* top-level and nested bindings.  It
 assumes that all variables bound in this group are already in scope.
 @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).
+This is done *either* by pass 3 (for the top-level bindings), *or* by
+@rnNestedMonoBinds@ (for the nested ones).

 
 \begin{code}
 
 \begin{code}

-rnMonoBinds :: RdrNameMonoBinds
-           -> [RenamedSig]     -- Signatures attached to this group
-           -> RnM_Fixes s (RenamedHsBinds, FreeVars)
-
-rnMonoBinds mbinds siglist
+rn_mono_binds :: TopLevelFlag
+             -> NameSet                -- Binders of this group
+             -> RdrNameMonoBinds       
+             -> [RdrNameSig]           -- Signatures attached to this group
+             -> RnMS s (RenamedHsBinds,        -- 
+                        FreeVars)      -- Free variables
+
+rn_mono_binds top_lev binders mbinds sigs

   =
         -- 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) ->
+    renameSigs top_lev False binders sigs      `thenRn` \ siglist ->
+    flattenMonoBinds siglist mbinds    `thenRn` \ mbinds_info ->

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

-    let vertices = mkVertices mbinds_info
-       edges   = mkEdges vertices 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 = unionManyNameSets [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.
 
 \begin{code}
 \end{code}
 
 @flattenMonoBinds@ is ever-so-slightly magical in that it sticks
 unique ``vertex tags'' on its output; minor plumbing required.
 
 \begin{code}

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

                 -> RdrNameMonoBinds
                 -> RdrNameMonoBinds

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

 
 

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

 
 

-flattenMonoBinds uniq sigs (AndMonoBinds mB1 mB2)
-  = flattenMonoBinds uniq sigs mB1     `thenRn` \ (uniq1, flat1) ->
-    flattenMonoBinds uniq1 sigs mB2    `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_and_binds locn)

   = pushSrcLocRn locn                  $
     rnPat pat                          `thenRn` \ pat' ->
     rnGRHSsAndBinds grhss_and_binds    `thenRn` \ (grhss_and_binds', fvs) ->
 
         -- Find which things are bound in this group
     let
   = pushSrcLocRn locn                  $
     rnPat pat                          `thenRn` \ pat' ->
     rnGRHSsAndBinds grhss_and_binds    `thenRn` \ (grhss_and_binds', fvs) ->
 
         -- 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
+       sigs_fvs         = foldr sig_fv emptyNameSet sigs_for_me

     in
     in

-    returnRn (
-       uniq + 1,
-       [(uniq,
-         mkUniqSet names_bound_here,
-          fvs `unionUniqSets` sigs_fvs,
-          PatMonoBind pat' grhss_and_binds' locn,
-          sigs_etc_for_here
+    returnRn 
+       [(names_bound_here,
+         fvs `unionNameSets` sigs_fvs,
+         PatMonoBind pat' grhss_and_binds' locn,
+         sigs_for_me

         )]
         )]

-    )

 
 

-flattenMonoBinds uniq sigs (FunMonoBind name inf matches locn)
+flattenMonoBinds sigs (FunMonoBind name inf matches locn)

   = pushSrcLocRn locn                           $
   = pushSrcLocRn locn                           $

-    lookupValue name                            `thenRn` \ name' ->
-    mapAndUnzipRn rnMatch matches               `thenRn` \ (new_matches, fv_lists) ->
-    mapRn (checkPrecMatch inf name') new_matches `thenRn_`
+    mapRn (checkPrecMatch inf name) matches    `thenRn_`
+    lookupBndrRn name                          `thenRn` \ name' ->
+    mapAndUnzipRn rnMatch matches              `thenRn` \ (new_matches, fv_lists) ->

     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
+       fvs         = unionManyNameSets fv_lists
+       sigs_for_me = sigsForMe (name' ==) sigs
+       sigs_fvs    = foldr sig_fv emptyNameSet sigs_for_me

     in
     in

-    returnRn (
-      uniq + 1,
-      [(uniq,
-       unitUniqSet name',
-       fvs `unionUniqSets` sigs_fvs,
+    returnRn
+      [(unitNameSet name',
+       fvs `unionNameSets` sigs_fvs,

        FunMonoBind name' inf new_matches locn,
        sigs_for_me
        )]
        FunMonoBind name' inf new_matches locn,
        sigs_for_me
        )]

-    )

 \end{code}
 
 \end{code}
 

-Grab type-signatures/user-pragmas of interest:
+
+@rnMethodBinds@ is used for the method bindings of an instance
+declaration.   like @rnMonoBinds@ but without dependency analysis.
+

 \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
+rnMethodBinds :: RdrNameMonoBinds -> RnMS s RenamedMonoBinds
+
+rnMethodBinds EmptyMonoBinds = returnRn EmptyMonoBinds

 
 

+rnMethodBinds (AndMonoBinds mb1 mb2)
+  = andRn AndMonoBinds (rnMethodBinds mb1)
+                      (rnMethodBinds mb2)
+
+rnMethodBinds (FunMonoBind name inf matches locn)
+  = pushSrcLocRn locn                             $
+    mapRn (checkPrecMatch inf name) matches    `thenRn_`
+
+    lookupGlobalOccRn name                     `thenRn` \ sel_name -> 
+       -- We use the selector name as the binder
+
+    mapAndUnzipRn rnMatch matches              `thenRn` \ (new_matches, _) ->
+    returnRn (FunMonoBind sel_name inf new_matches locn)
+
+rnMethodBinds (PatMonoBind (VarPatIn name) grhss_and_binds locn)
+  = pushSrcLocRn locn                  $
+    lookupGlobalOccRn name                     `thenRn` \ sel_name -> 
+    rnGRHSsAndBinds grhss_and_binds    `thenRn` \ (grhss_and_binds', _) ->
+    returnRn (PatMonoBind (VarPatIn sel_name) grhss_and_binds' locn)
+
+-- Can't handle method pattern-bindings which bind multiple methods.
+rnMethodBinds mbind@(PatMonoBind other_pat _ locn)
+  = pushSrcLocRn locn  $
+    failWithRn EmptyMonoBinds (methodBindErr mbind)
+\end{code}
+
+\begin{code}

 -- 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
 
 -- 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 (SpecSig _ _ (Just blah) _) acc = acc `unionNameSets` (unitNameSet blah)

 sig_fv _                          acc = acc
 \end{code}
 
 sig_fv _                          acc = acc
 \end{code}
 

@@ -399,55 +383,17 @@ 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

 
 

-reconstructRec cycles edges mbi
-  = foldr1 ThenBinds (map (reconstructCycle mbi) cycles)
+reconstructCycle (AcyclicSCC (_, _, binds, sigs))
+  = MonoBind binds sigs NonRecursive
+
+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}
 
 %************************************************************************

@@ -463,35 +409,24 @@ 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
-    ]
+  = (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 :: FlatMonoBindsInfo -> [VertexTag]
-mkVertices info = [ vertex | (vertex,_,_,_,_) <- info]
-
-mkEdges :: [VertexTag] -> FlatMonoBindsInfo -> [Edge]
-
-mkEdges vertices flat_info
- -- An edge (v,v') indicates that v depends on v'
- = [ (source_vertex, target_vertex)
-   | (source_vertex, _, used_names, _, _) <- flat_info,
-     target_name   <- uniqSetToList used_names,
-     target_vertex <- vertices_defining target_name 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
-      ]
+mkEdges :: [(FlatMonoBindsInfo, VertexTag)] -> [(FlatMonoBindsInfo, VertexTag, [VertexTag])]
+
+mkEdges flat_info
+  = [ (info, tag, dest_vertices (nameSetToList names_used))
+    | (info@(names_defined, names_used, mbind, sigs), tag) <- flat_info
+    ]
+  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}
 
 

@@ -501,141 +436,103 @@ mkEdges vertices flat_info
 %*                                                                     *
 %************************************************************************
 
 %*                                                                     *
 %************************************************************************
 

-@rnBindSigs@ checks for: (a)~more than one sig for one thing;
+@renameSigs@ 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.
 
 \begin{code}
 (b)~signatures given for things not bound here; (c)~with suitably
 flaggery, that all top-level things have type signatures.
 
 \begin{code}

-rnBindSigs :: Bool                     -- True <=> top-level binders
-           -> [RdrName]                -- Binders for this decl group
+renameSigs :: TopLevelFlag
+           -> Bool                     -- True <-> sigs for an instance decl
+                                       -- hence SPECIALISE instance prags ok
+           -> NameSet                  -- Set of names bound in this group

            -> [RdrNameSig]
            -> [RdrNameSig]

-           -> RnM_Fixes s [RenamedSig] -- List of Sig constructors
+           -> RnMS s [RenamedSig]               -- 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
+renameSigs top_lev inst_decl binders sigs
+  =     -- Rename the signatures
+    mapRn renameSig sigs       `thenRn` \ sigs' ->

 
 

-        -- Discard unbound ones we've already complained about, so we
-        -- complain about duplicate ones.
-
-       (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
+       spec_inst_sigs  = [s | s@(SpecInstSig _ _) <- goodies]
+       type_sig_vars   = [n | Sig n _ _ <- goodies]
+       sigs_required   = case top_lev of {TopLevel -> opt_SigsRequired; NotTopLevel -> False}
+       un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars
+                       | otherwise     = []

     in
     in

-    mapRn (addErrRn . dupSigDeclErr) dups `thenRn_`
-
-    getSrcLocRn                        `thenRn` \ locn ->
-
-    (if (is_toplev && opt_SigsRequired) then
-       let
-           sig_frees = catMaybes (map (sig_free sigs) binder_occnames)
-       in
-       mapRn (addErrRn . missingSigErr locn) sig_frees
+    mapRn dupSigDeclErr dups                           `thenRn_`
+    mapRn unknownSigErr not_this_group                 `thenRn_`
+    (if not inst_decl then
+       mapRn unknownSigErr spec_inst_sigs

      else
        returnRn []
      else
        returnRn []

-    )                          `thenRn_`
+    )                                                  `thenRn_`
+    mapRn (addErrRn.missingSigErr) un_sigd_binders     `thenRn_`

 
     returnRn sigs' -- bad ones and all:
                   -- we need bindings of *some* sort for every name
 
     returnRn sigs' -- bad ones and all:
                   -- we need bindings of *some* sort for every name

+
+
+renameSig (Sig v ty src_loc)
+  = pushSrcLocRn src_loc $
+    lookupBndrRn v                             `thenRn` \ new_v ->
+    rnHsSigType (quotes (ppr v)) ty            `thenRn` \ new_ty ->
+    returnRn (Sig new_v new_ty src_loc)
+
+renameSig (SpecInstSig ty src_loc)
+  = pushSrcLocRn src_loc $
+    rnHsSigType (text "A SPECIALISE instance pragma") ty               `thenRn` \ new_ty ->
+    returnRn (SpecInstSig new_ty src_loc)
+
+renameSig (SpecSig v ty using src_loc)
+  = pushSrcLocRn src_loc $
+    lookupBndrRn v                     `thenRn` \ new_v ->
+    rnHsSigType (quotes (ppr v)) ty    `thenRn` \ new_ty ->
+    rn_using using                     `thenRn` \ new_using ->
+    returnRn (SpecSig new_v new_ty new_using src_loc)

   where
   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;
+    rn_using Nothing  = returnRn Nothing
+    rn_using (Just x) = lookupOccRn x `thenRn` \ new_x ->
+                       returnRn (Just new_x)
+
+renameSig (InlineSig v src_loc)
+  = pushSrcLocRn src_loc $
+    lookupBndrRn v             `thenRn` \ new_v ->
+    returnRn (InlineSig new_v src_loc)
+
+renameSig (NoInlineSig v src_loc)
+  = pushSrcLocRn src_loc $
+    lookupBndrRn v             `thenRn` \ new_v ->
+    returnRn (NoInlineSig new_v src_loc)
+\end{code}
+
+Checking for distinct signatures; oh, so boring
+
+\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...
        -- 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)"
+       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 _                         = panic# "tag(RnBinds)"

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

@@ -645,46 +542,33 @@ 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)
+
+missingSigErr 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}