[ruby/irb] follow up the actual line number

https://github.com/ruby/irb/commit/7aed8fe3b1

lib/irb/ruby-lex.rb

@@ -223,7 +223,10 @@ class RubyLex
             throw :TERM_INPUT if @line == ''
           else
             @line_no += l.count("\n")
-            next if l == "\n"
+            if l == "\n"
+              @exp_line_no += 1
+              next
+            end
             @line.concat l
             if @code_block_open or @ltype or @continue or @indent > 0
               next

test/irb/test_context.rb

@@ -572,5 +572,26 @@ module TestIRB
     ensure
       $VERBOSE = verbose
     end
+
+    def test_lineno
+      input = TestInputMethod.new([
+        "\n",
+        "__LINE__\n",
+        "__LINE__\n",
+        "\n",
+        "\n",
+        "__LINE__\n",
+      ])
+      irb = IRB::Irb.new(IRB::WorkSpace.new(Object.new), input)
+      out, err = capture_output do
+        irb.eval_input
+      end
+      assert_empty err
+      assert_pattern_list([
+          :*, /\b2\n/,
+          :*, /\b3\n/,
+          :*, /\b6\n/,
+        ], out)
+    end
   end
 end