diff --git a/src/Defun.ml b/src/Defun.ml
index 1441922..6d634be 100644
--- a/src/Defun.ml
+++ b/src/Defun.ml
@@ -66,7 +66,6 @@ let rec walk_term fs t =
             let fs, nNext = walk_term fs next in
             fs, T.LetVal(var, value, nNext)
     | S.LetBlo (var, S.Lam(self, vars, body), next) ->
-            (* FIXME is handling of recursive functions correct? *)
             let fs, nNext = walk_term fs next in
             let fs, nBody = walk_term fs body in
             let arity = List.length vars + 1 in
@@ -77,18 +76,24 @@ let rec walk_term fs t =
                 vars
                 (S.vvars (List.tl args)) in
             let thisTag = freshTag () in
-            let selfVars = (match self with
-                | S.Self self -> Atom.Set.singleton self
-                | S.NoSelf -> Atom.Set.empty) in
-            let freeVars = Atom.Set.elements @@
+            let freeVars =
                 Atom.Set.diff
                     (S.fv_term body)
-                    (Atom.Set.union (Atom.Set.of_list vars) selfVars)
+                    (Atom.Set.of_list vars)
                 in
+            let freeVarsBranch, freeVarsCon = (match self with
+                | S.Self self ->
+                        let freeVars = Atom.Set.elements @@
+                            Atom.Set.diff freeVars
+                                (Atom.Set.singleton self) in
+                        self :: freeVars, var :: freeVars
+                | S.NoSelf ->
+                        let freeVars = Atom.Set.elements freeVars in
+                        freeVars, freeVars) in
             let thisFunc =
-                T.Branch(thisTag, freeVars, nBody) in
+                T.Branch(thisTag, freeVarsBranch, nBody) in
             let fs = add_func fs arity thisFunc in
-            fs, T.LetBlo (var, T.Con(thisTag, T.vvars freeVars), nNext)
+            fs, T.LetBlo (var, T.Con(thisTag, T.vvars freeVarsCon), nNext)
     | S.IfZero (value, tIf, tElse) ->
             let fs, tIf = walk_term fs tIf in
             let fs, tElse = walk_term fs tElse in