Issue #19708 has been updated by AMomchilov (Alexander Momchilov). You can workaround this by using `attr_reader` to create the optimized method, `alias_method` to give it the nice `active?` name, and then `remove_method` to delete the original non-`?` name: ```ruby module PredicateHelper # Or just monkey-patch Module, I won't sue :D def define_predicate(predicate_name) ivar_name = predicate_name.to_s.delete_suffix("?") attr_reader(ivar_name) alias_method(predicate_name, ivar_name) remove_method(ivar_name) end end ``` Usage: ```ruby class Person extend PredicateHelper attr_reader :name, :age define_predicate :active? def initialize @name = "Bob" @age = 30 @active = true end end bob = Person.new p [bob.name, bob.age, bob.active?] # ["Bob", 30, true] # Shows that `#active?` is just aliasing the now-deleted `#active` p Person.instance_method(active?) # => #<UnboundMethod: Person#active?(active)() Untitled 2.rb:6> ``` ---------------------------------------- Feature #19708: Support `attr_reader :foo?` https://bugs.ruby-lang.org/issues/19708#change-103391 * Author: AMomchilov (Alexander Momchilov) * Status: Open * Priority: Normal ---------------------------------------- Creating reader methods with `attr_reader` is preferable over defining them by hand, not only because it's more convenient, but also because it hits a fast path in MRI (see `VM_METHOD_TYPE_IVAR`). Since local and instance variables can't end with `?`, you can't use `attr_reader` to define predicate-style methods for boolean values, like: ```ruby class Person attr_reader(:name, :age, :active?) # invalid attribute name `active?' (NameError) def initialize @name = "Bob" @age = 30 @active = true end end ``` It would be nice if `attr_reader` (and friends) could behave like: ```ruby def active? = @active ``` (`attr_writer` and `attr_accessor` couldn't do the same, since `def active?=(new_value)` isn't valid, so they'd probably stick with `def active=(new_value)`) -- https://bugs.ruby-lang.org/