Regular expressions

Element in class is already covered  

Reports the elements in regular expression character classes that are already covered by another element in the same class.

Invalid delimiter  

Reports invalid delimiters in regular expressions in two cases: 1.

Ranges in class can be merged  

Reports the alphabetic ranges or characters in regular expression character classes that only adjust the already existing ranges.

Redundant modifier  

Reports the i (case insensitivity) modifiers that are used in regular expression patterns containing no letters.

Unsupported modifier  

Reports the usages of the e modifier in regular expression patterns.