title: How to fix `Implementation of 'Protocol' cannot be automatically synthesized in an extension`?
body: <p>I'm getting a compiler error while adding new protocol conformance to an extension.</p>
  <pre><code>struct EquatableStruct { }
  
  extension EquatableStruct: Equatable {
    static func == (lhs: EquatableStruct, rhs: EquatableStruct) -&gt; Bool {
      return true
    }
  }
  </code></pre>
  <p>Here I'm getting the compiler error:</p>
  <blockquote>
  <p><code>Implementation of 'Equatable' cannot be automatically synthesized in an extension</code></p>
  </blockquote>
  <p>How do I fix this issue?</p>