## Why is this an issue?

By default case insensitivity only affects letters in the ASCII range. This can be changed by either passing `Pattern.UNICODE_CASE` or `Pattern.UNICODE_CHARACTER_CLASS` as an argument to `Pattern.compile` or using `(?u)` or `(?U)` within the regex.

If not done, regular expressions involving non-ASCII letters will still handle those letters as being case sensitive.

### Noncompliant code example

    Pattern.compile("söme pättern", Pattern.CASE_INSENSITIVE);
    str.matches("(?i)söme pättern");
    str.matches("(?i:söme) pättern");

### Compliant solution

    Pattern.compile("söme pättern", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    str.matches("(?iu)söme pättern");
    str.matches("(?iu:söme) pättern");

    // UNICODE_CHARACTER_CLASS implies UNICODE_CASE
    Pattern.compile("söme pättern", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CHARACTER_CLASS);
    str.matches("(?iU)söme pättern");
    str.matches("(?iU:söme) pättern");