title: Type of expression is ambiguous without more context Swift
body: <p>I am getting a '<strong>Type of expression is ambiguous without more context</strong> ' on this part of code from a project I am trying to upgrade to latest Swift version. I can't seem to figure it out. I tried different things but can't get it to work.</p>
  
  <p>The problem is on the syntax of this line </p>
  
  <pre><code>let imageToDeleteParameters  = imagesToDelete.map { ["id": $0.id, "url": $0.url.absoluteString, "_destroy": true] }
  </code></pre>
  
  <p>Full code:</p>
  
  <pre><code>extension TutorialCreationRequest: WebserviceParametrable {
      func toParameters() -&gt; [String: AnyObject] {
          let imageParameters = images.map { ["url": $0] }
          let imageToDeleteParameters  = imagesToDelete.map { ["id": $0.id, "url": $0.url.absoluteString, "_destroy": true] }
          return [
              "title": title,
              "is_draft": isDraft,
              "difficulty": difficulty,
              "duration": duration,
              "cost": cost,
              "user_id": userId,
              "description": description,
              "to_sell": toSell,
              "images": [imageParameters, imageToDeleteParameters].flatMap { $0 }
          ]
      }
  }
  </code></pre>