X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Frename%2FRnBinds.lhs;h=6c57cb2aa887f2cd73e89d3be67491a832e5ea95;hb=6cec61d14a324285dbb8ce73d4c7215f1f8d6766;hp=4899adb07773e2c7c2c51649af3b2fdb51c30ef8;hpb=92267aa26adb1ab5a6d8004a80fdf6aa06ea4e44;p=ghc-hetmet.git

diff --git a/compiler/rename/RnBinds.lhs b/compiler/rename/RnBinds.lhs
index 4899adb..6c57cb2 100644
--- a/compiler/rename/RnBinds.lhs
+++ b/compiler/rename/RnBinds.lhs
@@ -357,7 +357,9 @@ 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: 
@@ -773,7 +775,7 @@ 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')