in reply to
Fun with Typed Objects 1
I had to do some digging, but Larry's Apocalypses, especially Apocalypse Two have the answer, at least as phrased by The Great One in 2001.
RFC 218: my Dog $spot Is Just an Assertion
I expect that a declaration of the form:
my Dog $spot;
is merely an assertion that you will not use $spot inconsistently with it being a Dog.
Later, he says that:
This bare declaration does not call a constructor; however, there may be forms of declaration that do.
Of course, they say "The Devil can quote Scripture for his own purposes."