diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 08ff5caa882..ff614e30eed 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2005-05-19  Jonathan Wakely  <redi@gcc.gnu.org>
+
+	* include/bits/basic_string.h (operator[]): Allow s[s.size()] in
+	debug mode, but not pedantic mode.
+
 2005-05-19  Jan Beulich  <jbeulich@novell.com>
 
 	* libsupc++/unwind-cxx.h: Include cstdlib.
diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index b1fbaaac4d0..35dd364d969 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -695,7 +695,10 @@ namespace std
       reference
       operator[](size_type __pos)
       {
-	_GLIBCXX_DEBUG_ASSERT(__pos < size());
+        // allow pos == size() as v3 extension:
+	_GLIBCXX_DEBUG_ASSERT(__pos <= size());
+        // but be strict in pedantic mode:
+	_GLIBCXX_DEBUG_PEDASSERT(__pos < size());
 	_M_leak();
 	return _M_data()[__pos];
       }