omg.diff

diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
index e948314..a24b35a 100644
--- a/activesupport/lib/active_support/callbacks.rb
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -321,7 +321,13 @@ module ActiveSupport
 
           _normalize_legacy_filter(kind, filter)
           scopes = Array(chain.config[:scope])
-          method_to_call = scopes.map{ |s| s.is_a?(Symbol) ? send(s) : s }.join("_")
+          method_to_call = scopes.map { |s|
+            if s.is_a?(Symbol)
+              send(s)
+            else
+              raise("I am glad that this code was totally test driven")
+            end
+          }.join("_")
 
           @klass.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
             def #{method_name}(&blk)

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