Currently product filters provide information on overriding them here:

    # THIS FILE SHOULD BE OVER-RIDDEN IN YOUR SITE EXTENSION!
    #   the exact code probably won't be useful, though you're welcome to modify and reuse
    #   the current contents are mainly for testing and documentation

    # To override this file...
    #   1) Make a copy of it in your sites local /lib/spree folder
    #   2) Add it to the config load path, or require it in an initializer, e.g...
    #
    #      # config/initializers/spree.rb
    #      require 'spree/product_filters'

Note: It is also unnecessarily required in a couple of tests.

However, the version that exists in core is being required in the Taxon model, here.

On a new Rails/Solidus app, you have to remove lib/spree from the autoloads (as lib is autoloaded by default now), and then make lib/spree/core/product_filters.rb file, stopping the version in core from being loaded. You need the version in core not be loaded if you want to define your own price_range_any or brand_any search scopes.

We should remove the require in the Taxon model. The Starter Frontend (which depends on the stock product filters) already explicitly requires the module.