diff --git a/core/block/meta/pubsub.go b/core/block/meta/pubsub.go
index e54db16a2..cd1cbcdc7 100644
--- a/core/block/meta/pubsub.go
+++ b/core/block/meta/pubsub.go
@@ -367,9 +367,9 @@ func (c *collector) close() {
 }
 
 func copyMeta(m Meta) Meta {
-	var d *types.Struct
+	d := m.Details
 	if d != nil {
-		d = pbtypes.CopyStruct(m.SmartBlockMeta.Details)
+		d = pbtypes.CopyStruct(m.Details)
 	}
 	return Meta{
 		BlockId:
diff --git a/util/pbtypes/copy.go b/util/pbtypes/copy.go
index 91a29b476..536b0fbab 100644
--- a/util/pbtypes/copy.go
+++ b/util/pbtypes/copy.go
@@ -13,11 +13,6 @@ var bytesPool = &sync.Pool{
 	},
 }
 
-type Type interface {
-	Size() int
-	MarshalToSizedBuffer(data []byte) (int, error)
-}
-
 func CopyBlock(in *model.Block) (out *model.Block) {
 	buf := bytesPool.Get().([]byte)
 	size := in.Size()
diff --git a/util/pbtypes/copy_test.go b/util/pbtypes/copy_test.go
new file mode 100644
index 000000000..8dbd2987a
--- /dev/null
+++ b/util/pbtypes/copy_test.go
@@ -0,0 +1,19 @@
+package pbtypes
+
+import (
+	"testing"
+
+	"github.com/gogo/protobuf/types"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCopyStruct(t *testing.T) {
+	s := &types.Struct{
+		Fields: map[string]*types.Value{
+			"string": String("string"),
+			"bool":   Bool(true),
+		},
+	}
+	c := CopyStruct(s)
+	assert.True(t, s.Equal(c))
+}