title: Dart: Target of URI does not exist
body: <p>My Dart app project structure:</p>
  
  <pre><code>myapp/
      pubspec.yaml
      pubspec.lock
      asset/
          ...assets
      build/
      packages/
      web/
          lookups/
              AjaxLookups.dart
          requests/
              RESTClient.dart
              AjaxRESTClient.dart
  </code></pre>
  
  <p>The <strong>AjaxLookups</strong> file:</p>
  
  <pre><code>library myapp;
  
  abstract class AjaxLookups {
      static final String BASE_URL = "/myapp";
      static final String DO_S0METHING_SERVICE_URL = BASE_URL + "/doSomething";
  }
  </code></pre>
  
  <p>The <strong>RESTClient</strong> file:</p>
  
  <pre><code>library myapp;
  
  typedef void Callback(String json);
  
  abstract class RESTClient {
      void get(String url, Callback onFail, Callback onSuccess);
  
      void post(String url, String dataJSON, Callback onFail, Callback onSuccess);
  }
  </code></pre>
  
  <p>The <strong>AjaxRESTClient</strong> file:</p>
  
  <pre><code>library myapp;
  
  import "RESTClient.dart";
  import "../lookups/AjaxLookups.dart";
  import "dart:html";
  import "dart:convert" show JSON;
  
  class AjaxRESTClient implements RESTClient, AjaxLookups {
      // ...
  }
  </code></pre>
  
  <p>Above, the import statement for <code>AjaxLookups</code> is causing a compiler error:</p>
  
  <blockquote>
    <p>Target of URI does not exist: '../request/AjaxLookups.dart'</p>
  </blockquote>
  
  <p>Why am I getting this? Why can't Dart find <code>../request/AjaxLookups.dart</code>? What do I need to do to fix it?</p>