title: Flutter - How to enable control-flow-collection?
body: <p>I'm trying use control-flow-collections in Flutter(Google's UI toolkit) to enable the use of inline <code>for</code> loop, i.e:</p>
  
  <pre><code>for (int i = 0; i &lt; globals.currentScaleList.scales.length; i++)
                Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: &lt;Widget&gt;[
                    Text(
                      globals.currentScaleList.scales[i].scaleType.toString(),
                      style: TextStyle(fontSize: 20.0),
                    ),
                  ],
                ),
            ], itemExtent: 23.0, onSelectedItemChanged: (index) {}),
  </code></pre>
  
  <p>I have seen the other questions on the topics in SO and followed all of the instructions that seem to work for others.</p>
  
  <ol>
  <li>I am running Flutter 1.15.4-pre.248 on the Master channel and Dart 2.8.0</li>
  </ol>
  
  <pre><code>Flutter 1.15.4-pre.248 • channel master • https://github.com/flutter/flutter.git
  Framework • revision 686d163420 (2 hours ago) • 2020-03-02 16:25:22 -0500
  Engine • revision 5e474ee860
  Tools • Dart 2.8.0 (build 2.8.0-dev.10.0 fbe9f6115d)
  </code></pre>
  
  <ol start="2">
  <li>I have created a analysis_options.yaml file in my root app folder and added the following:</li>
  </ol>
  
  <pre><code>analyzer:
    enable-experiment:
      - control-flow-collections
  </code></pre>
  
  <ol start="3">
  <li>I have also updated the min version of Dart in my pubspec.yaml, i.e.:</li>
  </ol>
  
  <pre><code>environment:
    sdk: "&gt;=2.5.0 &lt;3.0.0"
  </code></pre>
  
  <p>However, I still get the error against my 'for' loop stating:</p>
  
  <p>"This requires the 'control-flow-collections' experiment to be enabled.
  Try enabling this experiment by adding it to the command line when compiling and running."</p>
  
  <p>When I do enable the 3 lines in my analysis_options.yaml file, I get the warning:</p>
  
  <p>"The option 'control-flow-collection' isn't supported by 'enable-experiment'."</p>
  
  <p>What am I missing? Thanks</p>