Suppress Object#=~ deprecation warning

[koic]

This PR suppresses the following warning.

/Users/koic/src/github.com/rubocop-hq/rubocop-performance/lib/rubocop/cop/performance/string_replacement.rb:89:
warning: deprecated Object#=~ is called on RuboCop::AST::Node; it always
returns nil

Object#=~ has been deprecated from Ruby 2.6.
ruby/ruby@ebff9dc

Related commit: ruby/ruby@f7e94df

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[walf443]

I think it's better to use Regexp#match

DETERMINISTIC_REGEX.match(first_source)

Regexp#match? does not implemented on jruby

[koic]

Hmm, It looks like there is no advantage to replacing it with Regexp#match.

% git diff
diff --git a/lib/rubocop/cop/performance/string_replacement.rb b/lib/rubocop/cop/performance/string_replacement.rb
index 848180ec0..1ca8e9fe8 100644
--- a/lib/rubocop/cop/performance/string_replacement.rb
+++ b/lib/rubocop/cop/performance/string_replacement.rb
@@ -86,8 +86,7 @@ module RuboCop

           unless first_param.str_type?
             return true if options
-            return true unless first_source.is_a?(String) &&
-                               first_source =~ DETERMINISTIC_REGEX
+            return true unless DETERMINISTIC_REGEX.match(first_source)

             # This must be done after checking DETERMINISTIC_REGEX
             # Otherwise things like \s will trip us up

This change will cause the following TypeError.

% bundle exec rspec spec/rubocop/cop/performance/string_replacement_spec.rb

(snip)

Failures:

  1) RuboCop::Cop::Performance::StringReplacement non deterministic regex allows regex literal containing interpolations
     Failure/Error: return true unless DETERMINISTIC_REGEX.match(first_source)

     TypeError:
       no implicit conversion of RuboCop::AST::Node into String
     # ./lib/rubocop/cop/performance/string_replacement.rb:89:in `match'
     # ./lib/rubocop/cop/performance/string_replacement.rb:89:in `accept_first_param?'
     # ./lib/rubocop/cop/performance/string_replacement.rb:40:in `block in on_send'
     # ./lib/rubocop/cop/performance/string_replacement.rb:47:in `string_replacement?'
     # ./lib/rubocop/cop/performance/string_replacement.rb:38:in `on_send'
     # ./spec/rubocop/cop/performance/string_replacement_spec.rb:214:in `block (3 levels) in <top (required)>'

  2) RuboCop::Cop::Performance::StringReplacement non deterministic regex allows regex constructor containing regex with interpolations
     Failure/Error: return true unless DETERMINISTIC_REGEX.match(first_source)

     TypeError:
       no implicit conversion of RuboCop::AST::Node into String
     # ./lib/rubocop/cop/performance/string_replacement.rb:89:in `match'
     # ./lib/rubocop/cop/performance/string_replacement.rb:89:in `accept_first_param?'
     # ./lib/rubocop/cop/performance/string_replacement.rb:40:in `block in on_send'
     # ./lib/rubocop/cop/performance/string_replacement.rb:47:in `string_replacement?'
     # ./lib/rubocop/cop/performance/string_replacement.rb:38:in `on_send'
     # ./spec/rubocop/cop/performance/string_replacement_spec.rb:228:in `block (3 levels) in <top (required)>'

Finished in 0.14404 seconds (files took 1.53 seconds to load)
133 examples, 2 failures

I think it would be better to follow upstream changes.
ruby/ruby@f7e94df

[walf443]

I see. Thanks to consider it.