Expect T2723 to fail in 6.10

testsuite/tests/ghc-regress/rename/should_fail/all.T

@@ -69,5 +69,7 @@ test('rnfail055',
 test('rn_dup', normal, compile_fail, [''])
 test('T2310', normal, compile_fail, [''])
 test('T2490', normal, compile_fail, [''])
-test('T2723', normal, compile, [''])  # Warnings only
+test('T2723',
+     if_compiler_lt('ghc', '6.11', expect_fail),
+     compile, [''])  # Warnings only