False positive for Style/RedundantRegexpCharacterClass

[viraptor]

When using an escaped square bracket in a character class, rubocop suggests incorrect fix.

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Expected behavior

[(\[]TM[\])] passes the RedundantRegexpCharacterClass check.

Actual behavior

C: Style/RedundantRegexpCharacterClass: Redundant single-element character class, [\] can be replaced with \.

Steps to reproduce the problem

Run the check on a line with:

/\b ?[(\[]TM[\])]/i

RuboCop version

0.86.0 (using Parser 2.7.1.4, rubocop-ast 0.0.3, running on ruby 2.6.6 x86_64-darwin18)