## Why is this an issue?

A regex should never include a repetitive pattern whose body would match the empty string. This is usually a sign that a part of the regex is redundant or does not do what the author intended.

### Noncompliant code example

    "/(?:)*/"      // same as the empty regex, the '*' accomplishes nothing
    "/(?:|x)*/"    // same as the empty regex, the alternative has no effect
    "/(?:x|)*/"    // same as 'x*', the empty alternative has no effect
    "/(?:x*|y*)*/" // same as 'x*', the first alternative would always match, y* is never tried
    "/(?:x?)*/"    // same as 'x*'
    "/(?:x?)+/"    // same as 'x*'

### Compliant solution

    "/x*/"