diff --git a/spec/regexp-examples_spec.rb b/spec/regexp-examples_spec.rb
index a0f4d2d..6ad3acd 100644
--- a/spec/regexp-examples_spec.rb
+++ b/spec/regexp-examples_spec.rb
@@ -80,6 +80,8 @@ def self.examples_are_empty(*regexps)
         /[\\\]]/,
         /[\n-\r]/,
         /[\-]/,
+        /[-abc]/,
+        /[abc-]/,
         /[%-+]/, # This regex is "supposed to" match some surprising things!!!
         /['-.]/, # Test to ensure no "infinite loop" on character set expansion
         /[[abc]]/, # Nested groups