From @gfldex

sub niler{Nil}; my Int​:D $i where .defined = niler(); say $i; say $i.WHAT;
# OUTPUT«(<anon>)␤(<anon>)␤»
# expected​: well, I don't know since I explicitely asked for a defined
# value _twice_ but Nil is supposed to revert a container to it's default.
# That default is undefined, what can't work with $_.defined and should
# work (by design, not my opinion) with :D.
# Either way, I would like to get a type object when asking for WHAT.
# may be related to RT#​127958

From @zoffixznet

On Sat, 23 Jul 2016 15​:57​:33 -0700, gfldex wrote​:

sub niler{Nil}; my Int​:D $i where .defined = niler(); say $i; say $i.WHAT;
# OUTPUT«(<anon>)␤(<anon>)␤»
# expected​: well, I don't know since I explicitely asked for a defined
# value _twice_ but Nil is supposed to revert a container to it's default.
# That default is undefined, what can't work with $_.defined and should
# work (by design, not my opinion) with :D.
# Either way, I would like to get a type object when asking for WHAT.
# may be related to RT#​127958

Thanks for the report.

It's not empty. In both cases it says "<anon>", because you've used a `where` clause, thus creating an anonymous (nameless) subset.

If you prefer it to have a name, you can define a named subset instead​:

  <Zoffix__> m​: my Int $i where 42; say $i;
  <camelia> rakudo-moar bfb5279aa​: OUTPUT​: «(<anon>)␤»
  <Zoffix__> m​: subset Foo of Int where 42; my Foo $i ; say $i;
  <camelia> rakudo-moar bfb5279aa​: OUTPUT​: «(Foo)␤»

I made a patch that makes it say "<Int-based anon subset>" instead, but in the end decided against it,
because we use '<anon>' in many other places and this breaks that consistency, without adding much of extra information.

[1] https://gist.github.com/zoffixznet/198403153020a20b427bb2088b118ecc

Closing this as wontfix.

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

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