Style/StringLiterals does not work for Strings interpolated into a Regex

[vinnydiehl]

To reproduce

With default settings, run RuboCop on:

/foo#{"sar".sub("s", "b")}/

Expected behavior

A Style/StringLiterals warning, or maybe Style/StringLiteralsInInterpolation.

Actual behavior

No warnings.

RuboCop version

1.54.2 (using Parser 3.2.2.3, rubocop-ast 1.29.0, running on ruby 3.2.2) [x86_64-linux]

Other thoughts

Would it be better to use Style/StringLiteralsInInterpolation here, rather than Style/StringLiterals? This would be consistent with other interpolations, however, the rule isn't quite as important in this case since there are no external " to cause confusion, as there would be with a String or Symbol.

[jonas054]

Yes, this seems to be a bug. We've overlooked interpolations inside regular expressions.

Since Style/StringLiteralsInInterpolation currently covers interpolations inside string literals and inside symbol literals, it seems obvious that it should handle regexp literals too.

however, the rule isn't quite as important in this case since there are no external " to cause confusion

Agreed, but up until now we have not cared about this distinction. Style/StringLiteralsInInterpolation reports when the wrong kind of quotes are used even when there are no outer quotes to cause confusion, e.g. in heredocs. So I say we should just add regexp literals to the duties of Style/StringLiteralsInInterpolation and not worry about which delimiters those outer literals use.