I want to check whether an received item of type any implements encoding.TextUnmarshaller. The problem is, it’s method must be a pointer receiver, and this seems to be the source of quite some trouble.

type MyStruct struct{ value string }

var _ encoding.TextMarshaler = (*MyStruct)(nil)

func (id MyStruct) MarshalText() (text []byte, err error) {
    return []byte(id.value), nil
}

var _ encoding.TextUnmarshaler = (*MyStruct)(nil)

func (id *MyStruct) UnmarshalText(data []byte) error {
    *id = MyStruct{value: string(data)}
    return nil
}

func TestMyStruct(t *testing.T) {
    var ms any = MyStruct{value: "hello"} // ms comes from elsewhere
    _, ok := (ms).(encoding.TextMarshaler) // this will work b/c MyStruct is no pointer receiver here
    assert.True(t, ok)
    //_, ok = (ms).(encoding.TextUnmarshaler)
    //assert.True(t, ok) // this will fail b/c MyStruct is is a pointer receiver here
    v := reflect.ValueOf(ms)
    if assert.True(t, v.Type().NumMethod() > 0 && v.CanInterface()) {
        if v.CanAddr() { // it cannot
            _, ok := v.Addr().Interface().(encoding.TextUnmarshaler)
            assert.True(t, ok)
        } else {
            t.FailNow() // this is where I end up
        }
    }
}

Is there any (idiomatic) way to achieve that?