title: Code in directory expects import
body: <p>I have a package which is forked from a repository <code>myproject</code>. Inside the project, I want to use some functions from <code>sha3</code> package, however, I need to first add a <code>go</code> file to <code>sha3</code> package which contains some extra functionalities. I want to include this custom <code>sha3</code> package inside my project. I copied and pasted the <code>sha3</code> directory into <code>myproject</code> directory, and inside my <code>go</code> codes, I imported <code>sha3</code> package as:
  <code>import . "github.com/myproject/sha3"</code>. Now, when I try to build <code>myproject</code> package, I am getting:
  <code>code in directory /src/github.com/myproject/sha3 expects import "golang.org/x/crypto/sha3"</code>. I cannot understand what the problem is. I checked all the <code>go</code> files inside <code>sha3</code> directory and none of them requires any import! </p>