title: Laravel Passport API call code parameter null
body: <p>I'm trying to call a Laravel API using a Laravel Client. </p>
  
  <p><strong>Here is the code:</strong></p>
  
  <pre><code>Route::get('/callback', function (Request $request) {
      $http = new GuzzleHttp\Client;
  
      $response = $http-&gt;post('http://galaxy.dev/oauth/token', [
          'form_params' =&gt; [
              'grant_type' =&gt; 'authorization_code',
              'client_id' =&gt; '3',
              'client_secret' =&gt; 'rrhaEv0B6NAFLyMFqvZrY87gkquFF2UwhAHPtd8L',
              'redirect_uri' =&gt; 'http://galaxy-game.dev/callback',
              'code' =&gt; $request-&gt;code,
          ],
      ]);
      return json_decode((string) $response-&gt;getBody(), true);
  });
  </code></pre>
  
  <p><strong>I get this response from the API:</strong></p>
  
  <blockquote>
    <p>Client error: POST <a href="http://galaxy.dev/oauth/token" rel="nofollow noreferrer">http://galaxy.dev/oauth/token</a> resulted in a 400
    Bad Request response: {"error":"invalid_request","message":"The
    request is missing a required parameter, includes an invalid parameter
    value, (truncated...)</p>
  </blockquote>
  
  <p><strong>I have noticed in the API error log this:</strong></p>
  
  <blockquote>
    <p>Client->request('post', '<a href="http://galaxy.dev/oauth/token" rel="nofollow noreferrer">http://galaxy.dev/oauth/token</a>',
    array('form_params' => array('grant_type' => 'authorization_code',
    'client_id' => '3', 'client_secret' =>
    'rrhaEv0B6NAFLyMFqvZrY87gkquFF2UwhAHPtd8L', 'redirect_uri' =>
    '<a href="http://galaxy-game.dev/callback" rel="nofollow noreferrer">http://galaxy-game.dev/callback</a>', 'code' => null), 'synchronous' =>
    true)) in Client.php line 87</p>
  </blockquote>
  
  <p><strong>It says that</strong> </p>
  
  <blockquote>
    <p>$request->code = null</p>
  </blockquote>
  
  <p>Does anyone have any ideas why this might be? This seems to be the reason why it is failing. I have followed the Laravel docs exactly. Any help would be greatly appreciated! </p>