How to mixin and call link_to from controller in Rails?

This doesn't really answer your question but there is an easier way

For Rails 5, use the helpers proxy

helpers.link_to '...', '...'

For Rails 3 and 4, since you are using the helper from a controller you can use the view_context

# in the controller code
view_context.link_to '...', '...'

# instead of using your mixin code 
link_to '...', '...'

For Rails 2, since you are using the helper from a controller you can actually access the @template member variable of the controller, the @template is the view and already has the UrlHelper mixed in

# in the controller code
@template.link_to '...', '...'

# instead of using your mixin code 
link_to '...', '...'

if you need to use the urlhelper from code other than the controller, your solution is probably the way to go

Compatible with Rails 3,4 and 5:

view_context.link_to