title: Golang cannot use as type struct array or slice literal
body: <p>I'm trying to write a function in Go that takes a JSON with URLs of a directory and perform BFS to find files in that directory. When I find a JSON that is a directory, the code makes a URL and should enqueue that URL. When I try to create the struct in the <code>append()</code> in the loop, I get errors.</p>
  
  <pre><code>type ContentResp []struct {
      Name string `json:"name"`
      ContentType string `json:"type"`
      DownloadURL string `json:"download_url"`
  }
  ...
  
  var contentResp ContentResp
  search(contentQuery, &amp;contentResp)
  
  for _, cont := range contentResp {
          append(contentResp, ContentResp{Name:cont.Name, ContentType:"dir", DownloadURL:cont.contentDir.String()})
  }
  
  ./bfs.go:129: undefined: Name
  ./bfs.go:129: cannot use cont.Name (type string) as type struct { Name string "json:\"name\""; ContentType string "json:\"type\""; DownloadURL string "json:\"download_url\"" } in array or slice literal
  ./bfs.go:129: undefined: ContentType
  ./bfs.go:129: cannot use "dir" (type string) as type struct { Name string "json:\"name\""; ContentType string "json:\"type\""; DownloadURL string "json:\"download_url\"" } in array or slice literal
  ./bfs.go:129: undefined: DownloadURL
  ./bfs.go:129: cannot use cont.contentDir.String() (type string) as type struct { Name string "json:\"name\""; ContentType string "json:\"type\""; DownloadURL string "json:\"download_url\"" } in array or slice literal  
  </code></pre>