rails/rails — comment on commit 36253916b0b788d6ded56669d37c96ed05c92c5c
File:  line 0
By josevalim:

Memoizable implementation:

https://github.com/rails/rails/blob/36253916b0b788d6ded56669d37c96ed05c92c5c/activesupport/lib/active_support/memoizable.rb

Concern implementation:

https://github.com/rails/rails/blob/36253916b0b788d6ded56669d37c96ed05c92c5c/activesupport/lib/active_support/concern.rb#L107

They are very different things in terms of software complexity and how they
affect your code. The reason why Memoization is being removed is exactly
because it is **too complex** for something you can easily achieve in Ruby.