X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreUtils.lhs;h=ffbdb50422760f73e770f16f7bf1df8ce70dcc58;hp=b0de6f294dd59b81a69b40d5aef38b94987f82f5;hb=ac704fcac946590eef0ec91ae19f3b47d779a75f;hpb=28d732c362e13e58d653b3dc15fd376c3f0c54c2

diff --git a/compiler/coreSyn/CoreUtils.lhs b/compiler/coreSyn/CoreUtils.lhs
index b0de6f2..ffbdb50 100644
--- a/compiler/coreSyn/CoreUtils.lhs
+++ b/compiler/coreSyn/CoreUtils.lhs
@@ -1120,7 +1120,8 @@ eta_expand n us expr ty
 
               Lam lam_tv (eta_expand n us2 (App expr (Type (mkTyVarTy lam_tv))) (substTyWith [tv] [mkTyVarTy lam_tv] ty'))
                   where 
-                    lam_tv = mkTyVar (mkSysTvName uniq FSLIT("etaT")) (tyVarKind tv)
+                    lam_tv = setVarName tv (mkSysTvName uniq FSLIT("etaT"))
+			-- Using tv as a base retains its tyvar/covar-ness
                     (uniq:us2) = us 
  	; Nothing ->