1 files changed, 7 insertions, 0 deletions
diff --git a/lib/psych/exception.rb b/lib/psych/exception.rb
index f473b95..04a9a90 100644
--- a/lib/psych/exception.rb
+++ b/lib/psych/exception.rb
@@ -6,6 +6,13 @@ module Psych
   class BadAlias < Exception
   end
 
+  # Subclasses `BadAlias` for backwards compatibility
+  class AliasesNotEnabled < BadAlias
+    def initialize
+      super "Alias parsing was not enabled. To enable it, pass `aliases: true` to `Psych::load` or `Psych::safe_load`."
+    end
+  end
+
   class DisallowedClass < Exception
     def initialize action, klass_name
       super "Tried to #{action} unspecified class: #{klass_name}"