t a/lib/rdoc/ruby_lex.rb b/lib/rdoc/ruby_lex.rb

index e6e0b41..da17cd5 100644

--- a/lib/rdoc/ruby_lex.rb

+++ b/lib/rdoc/ruby_lex.rb

@@ -1028,6 +1028,8 @@ def identify_here_document

     end

     if output_heredoc then

+      raise Error, "Missing terminating #{quoted} for string" unless l

+

       doc << l.chomp

     else

       doc << '"'

diff --git a/test/rdoc/test_rdoc_ruby_lex.rb b/test/rdoc/test_rdoc_ruby_lex.rb

index 0dcb425..56ddf60 100644

--- a/test/rdoc/test_rdoc_ruby_lex.rb

+++ b/test/rdoc/test_rdoc_ruby_lex.rb

@@ -162,6 +162,18 @@ def test_class_tokenize_heredoc_indent

     assert_equal expected, tokens

   end

+  def test_class_tokenize_heredoc_missing_end

+    e = assert_raises RDoc::RubyLex::Error do

+      RDoc::RubyLex.tokenize <<-'RUBY', nil

+>> string1 = <<-TXT

+>" That's swell

+>" TXT

+      RUBY

+    end

+

+    assert_equal 'Missing terminating TXT for string', e.message

+  end

+

   def test_class_tokenize_heredoc_percent_N

     tokens = RDoc::RubyLex.tokenize <<-'RUBY', nil

 a b <<-U

-- 

1.8.4