From @AlexDaniel

Code​:
class C { method defined { True } }; say ?C

Result (2015.12,2016.02)​:
True

Result (2016.03,HEAD)​:
False

Bisectable points to rakudo/rakudo@24b4b23

The commit message did not indicate that �defined� method should no longer work, so my best guess is that the change is not intentional.

However, if this is not supposed to work, then what about throwing an error when the user attempts to create a �defined� method?

From @smls

A custom `.defined` method actually still works fine​:

  â�� class C { method defined { True } }; say C.defined
  True

But the `?` operator doesn't call `.defined`, it calls `.Bool`​:

  â�� class C { method Bool { True } }; say ?C
  True

Before the cited commit, class `Any` provided a default implementation for `.Bool` that delegated to `.defined`, and your custom class inherited that.

Now, the default implementation of `.Bool` checks `.DEFINITE` (via the `​:D` / `​:U` syntax) instead of `.defined`.

I don't know whether that subtle change was intentional, but it seems reasonable. Overriding `.defined` for a custom class is something that should only be necessary in rare situations, so it's not a great burden to ask users to also override method `.Bool` in those situations.

The RT System itself - Status changed from 'new' to 'open'

From @zoffixznet

On Mon, 23 Jan 2017 01​:37​:16 -0800, alex.jakimenko@​gmail.com wrote​:

Code​:
class C { method defined { True } }; say ?C

Result (2015.12,2016.02)​:
True

Result (2016.03,HEAD)​:
False

Bisectable points to
rakudo/rakudo@24b4b23

The commit message did not indicate that �defined� method should no
longer work, so my best guess is that the change is not intentional.

However, if this is not supposed to work, then what about throwing an
error when the user attempts to create a �defined� method?

+1 to smsl's and lizmat's response (on mailing list).

Custom `defined` method still works; the Bool method�which is what your operator calls�simply got decoupled from it.

The new behaviour is less surprising​: only what the user actually overrides is affected. And I agree with lizmat that is isn't a bug.

@zoffixznet - Status changed from 'open' to 'rejected'