Revert "alias_attribute: handle user defined source methods"

Author: byroot

activemodel/lib/active_model/attribute_methods.rb

@@ -215,17 +215,7 @@ def eagerly_generate_alias_attribute_methods(new_name, old_name) # :nodoc:
       end
 
       def generate_alias_attribute_methods(code_generator, new_name, old_name)
-        ActiveSupport::CodeGenerator.batch(code_generator, __FILE__, __LINE__) do |owner|
-          attribute_method_patterns.each do |pattern|
-            old_attribute_method = pattern.method_name(old_name)
-            if method_defined?(old_attribute_method, false)
-              alias_method(pattern.method_name(new_name), old_attribute_method)
-            else
-              define_attribute_method_pattern(pattern, old_name, owner: owner, as: new_name)
-            end
-          end
-          attribute_method_patterns_cache.clear
-        end
+        define_attribute_method(old_name, _owner: code_generator, as: new_name)
       end
 
       def alias_attribute_method_definition(code_generator, pattern, new_name, old_name) # :nodoc: