class RuboCop::Cop::Lint::InvalidCharacterLiteral

p(? )
@example
^
p(? )
-:1: syntax error, unexpected ‘?’, expecting ‘)’
-:1: warning: invalid character syntax; use ?s
p(? )
$ ruby -w
warning without syntax errors.
However, currently it’s unclear whether there’s a way to emit this
whitespace character (e.g. ‘? `).
This cop checks for invalid character literals with a non-escaped

def alternative_message(diagnostic) 

def alternative_message(diagnostic)
  diagnostic.message
    .capitalize
    .gsub('character syntax', 'character literal')
end

def relevant_diagnostic?(diagnostic) 

def relevant_diagnostic?(diagnostic)
  diagnostic.reason == :invalid_escape_use
end