[Fix rubocop#848] Fix a false positive for Rails/FreezeTime

Fixes rubocop#848.

This PR fixes a false positive for `Rails/FreezeTime`
when using `travel_to` with an argument of `Time.new(...).in_time_zone`.

Author: koic

changelog/fix_false_positive_for_rails_freeze_time.md

@@ -0,0 +1 @@
+* [#848](https://github.com/rubocop/rubocop-rails/issues/848): Fix a false positive for `Rails/FreezeTime` when using `travel_to` with an argument of `Time.new(...).in_time_zone`. ([@koic][])

lib/rubocop/cop/rails/freeze_time.rb

@@ -29,7 +29,7 @@ class FreezeTime < Base
 
         MSG = 'Use `freeze_time` instead of `travel_to`.'
         NOW_METHODS = %i[now new current].freeze
-        CONV_METHODS = %i[to_time in_time_zone].freeze
+        CONVERT_METHODS = %i[to_time in_time_zone].freeze
         RESTRICT_ON_SEND = %i[travel_to].freeze
 
         # @!method time_now?(node)
@@ -63,9 +63,11 @@ def current_time?(node, method_name)
         end
 
         def current_time_with_convert?(node, method_name)
-          return false unless CONV_METHODS.include?(method_name)
+          return false unless CONVERT_METHODS.include?(method_name)
+
+          child_node, child_method_name, time_argument = *node.children
+          return if time_argument
 
-          child_node, child_method_name = *node.children
           current_time?(child_node, child_method_name)
         end
       end

spec/rubocop/cop/rails/freeze_time_spec.rb

@@ -98,6 +98,12 @@
     RUBY
   end
 
+  it 'does not register an offense when using `travel_to` with an argument of `Time.new(...).in_time_zone`' do
+    expect_no_offenses(<<~RUBY)
+      travel_to(Time.new(2019, 4, 3, 12, 30).in_time_zone)
+    RUBY
+  end
+
   it 'does not register an offense when using `travel_to` without argument' do
     expect_no_offenses(<<~RUBY)
       travel_to