use NodeMutation to fetch file line

lib/synvert/core/rewriter/instance.rb

@@ -436,7 +436,8 @@ def add_action(action)
     #   end
     # @param message [String] warning message.
     def warn(message)
-      @rewriter.add_warning Rewriter::Warning.new(self, message)
+      line = @current_mutation.adapter.get_start_loc(@current_node).line
+      @rewriter.add_warning Rewriter::Warning.new(@file_path, line, message)
     end
 
     # It adds a callback when visiting an ast node.

lib/synvert/core/rewriter/warning.rb

@@ -5,11 +5,12 @@ module Synvert::Core
   class Rewriter::Warning
     # Initialize a Warning.
     #
-    # @param instance [Synvert::Core::Rewriter::Instance]
+    # @param file_path [String] file path.
+    # @param line [Integer] file line.
     # @param message [String] warning message.
-    def initialize(instance, message)
-      @file_path = instance.file_path
-      @line = instance.current_node.loc.expression.line
+    def initialize(file_path, line, message)
+      @file_path = file_path
+      @line = line
       @message = message
     end
 

spec/synvert/core/rewriter/instance_spec.rb

@@ -260,7 +260,9 @@ module Synvert::Core
     end
 
     it 'parses warn' do
-      expect(Rewriter::Warning).to receive(:new).with(instance, 'foobar')
+      instance.instance_variable_set(:@file_path, 'app/test.rb')
+      expect(@current_mutation).to receive_message_chain(:adapter, :get_start_loc, :line).and_return(2)
+      expect(Rewriter::Warning).to receive(:new).with('app/test.rb', 2, 'foobar')
       instance.warn 'foobar'
     end
 

spec/synvert/core/rewriter/warning_spec.rb

@@ -5,10 +5,7 @@
 module Synvert::Core
   describe Rewriter::Warning do
     subject {
-      source = "def test\n  debugger\nend"
-      send_node = Parser::CurrentRuby.parse(source).body.first
-      instance = double(current_node: send_node, file_path: 'app/test.rb')
-      Rewriter::Warning.new(instance, 'remove debugger')
+      Rewriter::Warning.new('app/test.rb', 2, 'remove debugger')
     }
 
     it 'gets message with filename and line number' do