Reports calls like s.substring(0, s.indexOf(x)) replaceable with s.substringBefore(x).

Using a corresponding functions makes your code simpler.

The quick-fix replaces a substring call with substringBefore.

Example:


  fun foo(s: String) {
      s.substring(0, s.indexOf('x'))
  }

After the quick-fix is applied:


  fun foo(s: String) {
      s.substringBefore('x')
  }