X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnBinds.lhs;h=286e3f28158f7bf619121a65cfec9abc80d0a15f;hp=4899adb07773e2c7c2c51649af3b2fdb51c30ef8;hb=224ef3094189bc9a33f23285b5dccbffdd8d7de0;hpb=92267aa26adb1ab5a6d8004a80fdf6aa06ea4e44

diff --git a/compiler/rename/RnBinds.lhs b/compiler/rename/RnBinds.lhs
index 4899adb..286e3f2 100644
--- a/compiler/rename/RnBinds.lhs
+++ b/compiler/rename/RnBinds.lhs
@@ -306,7 +306,10 @@ rnValBindsRHS trim mb_bound_names (ValBindsIn mbinds sigs)
            (anal_binds, anal_dus) -> return (valbind', valbind'_dus)
               where
                 valbind' = ValBindsOut anal_binds sigs'
-                valbind'_dus = usesOnly (hsSigsFVs sigs') `plusDU` anal_dus
+                valbind'_dus = anal_dus `plusDU` usesOnly (hsSigsFVs sigs')
+			       -- Put the sig uses *after* the bindings
+			       -- so that the binders are removed from 
+			       -- the uses in the sigs
        }
 
 rnValBindsRHS _ _ b = pprPanic "rnValBindsRHS" (ppr b)
@@ -357,7 +360,9 @@ rnLocalValBindsAndThen binds@(ValBindsIn _ sigs) thing_inside
 		-- 	let x = x in 3
 		-- should report 'x' unused
 	; let real_uses = findUses dus result_fvs
-	; warnUnusedLocalBinds bound_names real_uses
+	      -- Insert fake uses for variables introduced implicitly by wildcards (#4404)
+	      implicit_uses = hsValBindsImplicits binds'
+	; warnUnusedLocalBinds bound_names (real_uses `unionNameSets` implicit_uses)
 
 	; let
             -- The variables "used" in the val binds are: 
@@ -453,7 +458,7 @@ rnBind :: (Name -> [Name])		-- Signature tyvar function
 rnBind _ trim (L loc bind@(PatBind { pat_lhs = pat
                                    , pat_rhs = grhss 
                                       -- pat fvs were stored in bind_fvs
-                                      -- after processing the LHS          
+                                      -- after processing the LHS
                                    , bind_fvs = pat_fvs }))
   = setSrcSpan loc $ 
     do	{ let bndrs = collectPatBinders pat
@@ -473,7 +478,7 @@ rnBind sig_fn trim
                             , fun_infix = is_infix 
                             , fun_matches = matches })) 
        -- invariant: no free vars here when it's a FunBind
-  = setSrcSpan loc $ 
+  = setSrcSpan loc $
     do	{ let plain_name = unLoc name
 
 	; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $
@@ -697,7 +702,7 @@ renameSig _ (SpecInstSig ty)
 -- {-# SPECIALISE #-} pragmas can refer to imported Ids
 -- so, in the top-level case (when mb_names is Nothing)
 -- we use lookupOccRn.  If there's both an imported and a local 'f'
--- then the SPECIALISE pragma is ambiguous, unlike alll other signatures
+-- then the SPECIALISE pragma is ambiguous, unlike all other signatures
 renameSig mb_names sig@(SpecSig v ty inl)
   = do	{ new_v <- case mb_names of
                      Just {} -> lookupSigOccRn mb_names sig v
@@ -773,7 +778,7 @@ rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt)
 rnGRHS' :: HsMatchContext Name -> GRHS RdrName -> RnM (GRHS Name, FreeVars)
 rnGRHS' ctxt (GRHS guards rhs)
   = do	{ pattern_guards_allowed <- xoptM Opt_PatternGuards
-	; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $
+        ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $ \ _ ->
 				    rnLExpr rhs
 
 	; unless (pattern_guards_allowed || is_standard_guard guards')