title: .Contains closure: 'Bool' is ambiguous without more context [Solution: Optional String issue]
body: <p>Using this <a href="https://stackoverflow.com/a/31330465/7327018">code</a>, I tried to do an insensitive-case search to find companies for a certain major, but I get the error "Expression 'Bool' is ambiguous without more context" at <code>let isFound =</code>. </p>
  
  <p><strong>Why? How do I solve this?</strong></p>
  
  <p><code>company.majors</code> is a <code>String</code> array. <code>searchValue</code> is a lowercase <code>String</code></p>
  
  <pre><code>let searchValue = filterOptItem.searchValue?.lowercased()
  for company in allCompanies {
       //Insensitive case search
       let isFound = company.majors.contains({ $0.caseInsensitiveCompare(searchValue) == ComparisonResult.orderedSame })
       if (isFound) {
          filteredCompanies.insert(company)
       }
  }
  </code></pre>