Q: Why a regular expression `[A-z]` is considered suspicious I'm using PHPStorm with PHP Inspections. To validate a given value is in Base64 format I'm testing against the regular expression
^[A-z0-9/\+]+=*$

PHP Inspections mentions
'A-z' range in '[A-z0-9/\+]' is looking rather suspicious, please check.

I know A range of A-z means from character with code #65 to character with code #122. There is no other character than standard-latin characters in that range.
So I can't see anything suspicious with this regular expression. The only thing maybe, if there's any charset I don't know with any non-standard-latin characters in that mentioned range.
