1 files changed, 4 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 2677fade18..baeb653c61 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -8,6 +8,10 @@ module ActiveRecord
           raise ArgumentError, "#{options[:conditions]} was passed as :conditions but is not callable. " \
                                "Pass a callable instead: `conditions: -> { where(approved: true) }`"
         end
+        unless Array(options[:scope]).all? { |scope| scope.respond_to?(:to_sym) }
+          raise ArgumentError, "#{options[:scope]} is not supported format for :scope option. " \
+            "Pass a symbol or an array of symbols instead: `scope: :user_id`"
+        end
         super({ case_sensitive: true }.merge!(options))
         @klass = options[:class]
       end