Why can't I use a param called “action”?

Question

Is \"action\" as a input field name forbidden? Because everything works except the assignment of the \"action\" param.

Answer 1

I don't see why this would be invalid. You'd want to avoid conflicting with existing class or method names (e.g. not a good idea to define a method called action on a controller).

everything works except the assignment of the "action" param.

Does this generate an error? If so, what exactly?