title: Getting error: unknown field in struct literal
body: <p>I am trying to run this code:</p>
  
  <pre><code>type NullInt64 struct {
      sql.NullInt64
  }
  
  func ToNullInt64(s string) NullInt64 {
      i, err := strconv.Atoi(s)
      return NullInt64{Int64: int64(i), Valid: err == nil}
  }
  </code></pre>
  
  <p>but I get this error:</p>
  
  <pre><code>..\sql\sql.go:27: unknown NullInt64 field 'Int64' in struct literal
  ..\sql\sql.go:27: unknown NullInt64 field 'Valid' in struct literal
  </code></pre>