From @masak

<masak> r​: use MONKEY_TYPING; enum Weekday <Mon Tue Wed Thu Fri Sat
Sun>; augment class Weekday { multi method succ($ where Sun​:) { Mon }
}; say "alive"
<p6eval> rakudo f69e58​: OUTPUT«===SORRY!===␤Cannot auto-generate a
proto method in the setting␤»
<masak> why am I getting this error message?
<jnthn> masak​: Because it failed to detect the meta-object mismatch at
the point you started augmenting.
<jnthn> masak​: And then EnumHOW ain't set up to support multi-methods
being added.
<masak> where does the setting enter into the picture?
<jnthn> masak​: The code path that issues that is the one that you hit
if you don't explicitly write a proto when declaring a multi in the
setting.
<masak> so it tries to figure out what went wrong, and arrives at a
common cause which isn't applicable in this case?
<jnthn> Right.
* masak submits LTA rakudobug
<jnthn> Well, what's really LTA is it let you get that far.
<masak> aye.
<jnthn> Which I do want to fix. So yes, please file.

From @jnthn

On Tue May 15 14​:23​:56 2012, masak wrote​:

<masak> r​: use MONKEY_TYPING; enum Weekday <Mon Tue Wed Thu Fri Sat
Sun>; augment class Weekday { multi method succ($ where Sun​:) { Mon }
}; say "alive"
<p6eval> rakudo f69e58​: OUTPUT«===SORRY!===␤Cannot auto-generate a
proto method in the setting␤»
<masak> why am I getting this error message?
<jnthn> masak​: Because it failed to detect the meta-object mismatch at
the point you started augmenting.
<jnthn> masak​: And then EnumHOW ain't set up to support multi-methods
being added.
<masak> where does the setting enter into the picture?
<jnthn> masak​: The code path that issues that is the one that you hit
if you don't explicitly write a proto when declaring a multi in the
setting.
<masak> so it tries to figure out what went wrong, and arrives at a
common cause which isn't applicable in this case?
<jnthn> Right.
* masak submits LTA rakudobug
<jnthn> Well, what's really LTA is it let you get that far.
<masak> aye.
<jnthn> Which I do want to fix. So yes, please file.

Now gives a much gooder error​:

use MONKEY_TYPING; enum Weekday <Mon Tue Wed Thu Fri Sat Sun>; augment
class Weekday { multi method succ($ where Sun​:) { Mon } }; say "alive"
===SORRY!===
Cannot augment Weekday because it is closed
at <unknown file>​:1
------> Thu Fri Sat Sun>; augment class Weekday <HERE>{ multi method
succ($ where Sun​:) { Mon

I added a test that it threw the correct typed exception, so resolving.

/jnthn

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

@jnthn - Status changed from 'open' to 'resolved'