diff --git a/examples/_tests/multi/copygen.go b/examples/_tests/multi/copygen.go
index 4c2f978..2d3160b 100644
--- a/examples/_tests/multi/copygen.go
+++ b/examples/_tests/multi/copygen.go
@@ -330,6 +330,7 @@ func FuncExternalComplex(tC *complex.ComplexCollection, ff func(external.Collect
 // EmptyStruct copies a struct{} to a copygen.empty.
 func EmptyStruct(te copygen.empty, fs struct{}) {
 	// copygen.empty fields
+	te.e = fs
 }
 
 // Struct copies a copygen.Collection to a copygen.Collection.
diff --git a/examples/_tests/multi/setup/setup.go b/examples/_tests/multi/setup/setup.go
index e8a1577..8ae31ce 100644
--- a/examples/_tests/multi/setup/setup.go
+++ b/examples/_tests/multi/setup/setup.go
@@ -70,7 +70,7 @@ type Copygen interface {
 	FuncComplex(F func([]string, uint64) *byte) *complex.Collection
 	FuncExternalComplex(F func(external.Collection) []string) *complex.ComplexCollection
 
-	EmptyStruct(struct{}) empty
+	EmptyStruct(e struct{}) empty
 	Struct(Collection) Collection
 	StructExternal(external.Collection) *Collection
 }