diff --git a/vendor/github.com/modern-go/reflect2/safe_slice.go b/vendor/github.com/modern-go/reflect2/safe_slice.go
new file mode 100644
index 0000000..bcce6fd
--- /dev/null
+++ b/vendor/github.com/modern-go/reflect2/safe_slice.go
@@ -0,0 +1,92 @@
+package reflect2
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+type safeSliceType struct {
+	safeType
+}
+
+func (type2 *safeSliceType) SetIndex(obj interface{}, index int, value interface{}) {
+	val := reflect.ValueOf(obj).Elem()
+	elem := reflect.ValueOf(value).Elem()
+	val.Index(index).Set(elem)
+}
+
+func (type2 *safeSliceType) UnsafeSetIndex(obj unsafe.Pointer, index int, value unsafe.Pointer) {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) GetIndex(obj interface{}, index int) interface{} {
+	val := reflect.ValueOf(obj).Elem()
+	elem := val.Index(index)
+	ptr := reflect.New(elem.Type())
+	ptr.Elem().Set(elem)
+	return ptr.Interface()
+}
+
+func (type2 *safeSliceType) UnsafeGetIndex(obj unsafe.Pointer, index int) unsafe.Pointer {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) MakeSlice(length int, cap int) interface{} {
+	val := reflect.MakeSlice(type2.Type, length, cap)
+	ptr := reflect.New(val.Type())
+	ptr.Elem().Set(val)
+	return ptr.Interface()
+}
+
+func (type2 *safeSliceType) UnsafeMakeSlice(length int, cap int) unsafe.Pointer {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) Grow(obj interface{}, newLength int) {
+	oldCap := type2.Cap(obj)
+	oldSlice := reflect.ValueOf(obj).Elem()
+	delta := newLength - oldCap
+	deltaVals := make([]reflect.Value, delta)
+	newSlice := reflect.Append(oldSlice, deltaVals...)
+	oldSlice.Set(newSlice)
+}
+
+func (type2 *safeSliceType) UnsafeGrow(ptr unsafe.Pointer, newLength int) {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) Append(obj interface{}, elem interface{}) {
+	val := reflect.ValueOf(obj).Elem()
+	elemVal := reflect.ValueOf(elem).Elem()
+	newVal := reflect.Append(val, elemVal)
+	val.Set(newVal)
+}
+
+func (type2 *safeSliceType) UnsafeAppend(obj unsafe.Pointer, elem unsafe.Pointer) {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) SetNil(obj interface{}) {
+	val := reflect.ValueOf(obj).Elem()
+	val.Set(reflect.Zero(val.Type()))
+}
+
+func (type2 *safeSliceType) UnsafeSetNil(ptr unsafe.Pointer) {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) LengthOf(obj interface{}) int {
+	return reflect.ValueOf(obj).Elem().Len()
+}
+
+func (type2 *safeSliceType) UnsafeLengthOf(ptr unsafe.Pointer) int {
+	panic("does not support unsafe operation")
+}
+
+func (type2 *safeSliceType) Cap(obj interface{}) int {
+	return reflect.ValueOf(obj).Elem().Cap()
+}
+
+func (type2 *safeSliceType) UnsafeCap(ptr unsafe.Pointer) int {
+	panic("does not support unsafe operation")
+}