reflect; SetLen() requires an addressable value

src/reflect/value.go

@@ -999,7 +999,7 @@ func (v Value) SetLen(n int) {
 	if v.typecode.Kind() != Slice {
 		panic(&ValueError{Method: "reflect.Value.SetLen", Kind: v.Kind()})
 	}
-
+	v.checkAddressable()
 	hdr := (*sliceHeader)(v.value)
 	if int(uintptr(n)) != n || uintptr(n) > hdr.cap {
 		panic("reflect.Value.SetLen: slice length out of range")

src/reflect/value_test.go

@@ -180,6 +180,8 @@ func TestSlice(t *testing.T) {
 	}
 
 	// should be equivalent to s28 now, except for the capacity which doesn't change
+
+	s268ref = ValueOf(&s268).Elem()
 	s268ref.SetLen(6)
 	if len(s28) != s268ref.Len() || cap(s268) != s268ref.Cap() {
 		t.Errorf("SetLen: len(s268)=%d s268ref.Len()=%d cap(s268)=%d s268ref.Cap()=%d\n", len(s28), s268ref.Len(), cap(s268), s268ref.Cap())