[Fix rubocop#11549] Fix an error for third party cops

Fixes rubocop#11549.

This PR fixes an error for third party cops when inheriting `RuboCop::Cop::Cop`.
It makes the same changes to `RuboCop::Cop::Cop` as `RuboCop::Cop::Base` in rubocop#10839.
Confirmed that rubocop-i18n tests pass again.

changelog/fix_an_error_for_third_party_cops.md

@@ -0,0 +1 @@
+* [#11549](https://github.com/rubocop/rubocop/issues/11549): Fix an error for third party cops when inheriting `RuboCop::Cop::Cop`. ([@koic][])

lib/rubocop/cop/cop.rb

@@ -53,6 +53,11 @@ def self.qualified_cop_name(name, origin)
       def add_offense(node_or_range, location: :expression, message: nil, severity: nil, &block)
         @v0_argument = node_or_range
         range = find_location(node_or_range, location)
+
+        # Since this range may be generated from Ruby code embedded in some
+        # template file, we convert it to location info in the original file.
+        range = range_for_original(range)
+
         if block.nil? && !support_autocorrect?
           super(range, message: message, severity: severity)
         else
@@ -93,14 +98,21 @@ def on_investigation_end
         super
       end
 
-      private
-
-      def begin_investigation(processed_source)
+      # Called before any investigation
+      # @api private
+      def begin_investigation(processed_source, offset: 0, original: processed_source)
         super
         @offenses = current_offenses
         @last_corrector = @current_corrector
+
+        # We need to keep track of the original source and offset,
+        # because `processed_source` here may be an embedded code in it.
+        @current_offset = offset
+        @current_original = original
       end
 
+      private
+
       # Override Base
       def callback_argument(_range)
         @v0_argument
@@ -141,6 +153,14 @@ def suppress_clobbering
       rescue ::Parser::ClobberingError
         # ignore Clobbering errors
       end
+
+      def range_for_original(range)
+        ::Parser::Source::Range.new(
+          @current_original.buffer,
+          range.begin_pos + @current_offset,
+          range.end_pos + @current_offset
+        )
+      end
     end
   end
 end