[ruby-dev:52076] [Ruby master Bug#16297] calling undefined allocator by `Class.instance_method(:allocate)`

Issue #16297 has been updated by jhawthorn (John Hawthorn). I'm not sure if there's a deeper problem this causes, but it is still possible after this patch to call the allocator on a Rational through defining an arbitrary `allocate` method. ``` ruby => :allocate => (0/1) ``` ---------------------------------------- Bug #16297: calling undefined allocator by `Class.instance_method(:allocate)` https://bugs.ruby-lang.org/issues/16297#change-107083 * Author: nobu (Nobuyoshi Nakada) * Status: Closed * Backport: 2.5: REQUIRED, 2.6: DONE ---------------------------------------- For instance, `Rational.allocate` is undefined. ```ruby Rational.allocate #=> undefined method `allocate' for Rational:Class (NoMethodError) ``` But it can be called by `Class.instance_method(:allocate)`. ```ruby Class.instance_method(:allocate).bind_call(Rational) #=> (0/1) Class.instance_method(:allocate).bind(Rational).call #=> (0/1) ``` These allocators are defined for Marshal, and undefined as methods. -- https://bugs.ruby-lang.org/