1 files changed, 7 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
index 77af540c3e..66a0c83c41 100644
--- a/activerecord/lib/active_record/coders/yaml_column.rb
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -15,7 +15,13 @@ module ActiveRecord
       end
 
       def dump(obj)
-        YAML.dump(obj) unless obj.nil?
+        return if obj.nil?
+
+        unless obj.is_a?(object_class)
+          raise SerializationTypeMismatch,
+            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
+        end
+        YAML.dump obj
       end
 
       def load(yaml)