diff --git a/lang/core/iter/filter.go b/lang/core/iter/filter.go
index 17c72365..6e81662a 100644
--- a/lang/core/iter/filter.go
+++ b/lang/core/iter/filter.go
@@ -314,7 +314,7 @@ func (obj *FilterFunc) replaceSubGraph(subgraphInput interfaces.Func) error {
 	//	"filterCombineList0" -> "outputListFunc"
 	//	"filterCombineList1" -> "outputListFunc"
 	//	"filterCombineList2" -> "outputListFunc"
-	//	"outputListFunc" -> "subgraphOutput"
+	//	"outputListFunc" -> "filterSubgraphOutput"
 	// }
 	const channelBasedSinkFuncArgNameEdgeName = structs.ChannelBasedSinkFuncArgName // XXX: not sure if the specific name matters.
 
@@ -333,7 +333,7 @@ func (obj *FilterFunc) replaceSubGraph(subgraphInput interfaces.Func) error {
 	// create the new subgraph
 	obj.outputChan = make(chan types.Value)
 	subgraphOutput := &structs.ChannelBasedSinkFunc{
-		Name:     "subgraphOutput",
+		Name:     "filterSubgraphOutput",
 		Target:   obj,
 		EdgeName: channelBasedSinkFuncArgNameEdgeName,
 		Chan:     obj.outputChan,
diff --git a/lang/core/iter/map.go b/lang/core/iter/map.go
index 62d015d7..a9f96f4c 100644
--- a/lang/core/iter/map.go
+++ b/lang/core/iter/map.go
@@ -363,7 +363,7 @@ func (obj *MapFunc) replaceSubGraph(subgraphInput interfaces.Func) error {
 	//	"outputElem1" -> "outputListFunc"
 	//	"outputElem2" -> "outputListFunc"
 	//
-	//	"outputListFunc" -> "subgraphOutput"
+	//	"outputListFunc" -> "mapSubgraphOutput"
 	// }
 
 	const channelBasedSinkFuncArgNameEdgeName = structs.ChannelBasedSinkFuncArgName // XXX: not sure if the specific name matters.
@@ -377,7 +377,7 @@ func (obj *MapFunc) replaceSubGraph(subgraphInput interfaces.Func) error {
 
 	obj.outputChan = make(chan types.Value)
 	subgraphOutput := &structs.ChannelBasedSinkFunc{
-		Name:     "subgraphOutput",
+		Name:     "mapSubgraphOutput",
 		Target:   obj,
 		EdgeName: channelBasedSinkFuncArgNameEdgeName,
 		Chan:     obj.outputChan,
diff --git a/lang/funcs/structs/call.go b/lang/funcs/structs/call.go
index e841f171..a2cbde69 100644
--- a/lang/funcs/structs/call.go
+++ b/lang/funcs/structs/call.go
@@ -212,7 +212,7 @@ func (obj *CallFunc) replaceSubGraph(newFuncValue *full.FuncValue) error {
 	//   ArgVertices[1] -> ...
 	//   ArgVertices[2] -> ...
 	//
-	//   outputFunc -> "subgraphOutput"
+	//   outputFunc -> "callSubgraphOutput"
 	// }
 
 	// delete the old subgraph
@@ -233,7 +233,7 @@ func (obj *CallFunc) replaceSubGraph(newFuncValue *full.FuncValue) error {
 	obj.outputChan = make(chan types.Value)
 	edgeName := ChannelBasedSinkFuncArgName
 	subgraphOutput := &ChannelBasedSinkFunc{
-		Name:     "subgraphOutput",
+		Name:     "callSubgraphOutput",
 		Target:   obj,
 		EdgeName: edgeName,
 		Chan:     obj.outputChan,