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== Noncompliant Code Example

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/(?:)*/      // 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*'
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== Compliant Solution

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/x*/
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