Accept a symbol for `:in` option on inclusion and exclusion validators

1 files changed, 10 insertions, 3 deletions

diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
index 643a6f2b7c..cf1415b6c2 100644
--- a/activemodel/lib/active_model/validations/clusivity.rb
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -3,11 +3,11 @@ require 'active_support/core_ext/range.rb'
 module ActiveModel
   module Validations
     module Clusivity #:nodoc:
-      ERROR_MESSAGE = "An object with the method #include? or a proc or lambda is required, " <<
+      ERROR_MESSAGE = "An object with the method #include? or a proc, lambda or symbol is required, " <<
                       "and must be supplied as the :in (or :within) option of the configuration hash"
 
       def check_validity!
-        unless [:include?, :call].any?{ |method| delimiter.respond_to?(method) }
+        unless delimiter.respond_to?(:include?) || delimiter.respond_to?(:call) || delimiter.respond_to?(:to_sym)
           raise ArgumentError, ERROR_MESSAGE
         end
       end
@@ -15,7 +15,14 @@ module ActiveModel
     private
 
       def include?(record, value)
-        exclusions = delimiter.respond_to?(:call) ? delimiter.call(record) : delimiter
+        exclusions = if delimiter.respond_to?(:call)
+                       delimiter.call(record)
+                     elsif delimiter.respond_to?(:to_sym)
+                       record.send(delimiter)
+                     else
+                       delimiter
+                     end
+
         exclusions.send(inclusion_method(exclusions), value)
       end