Anonymous shapes are considered empty shapes

[labra]

Given the following schema:

PREFIX :       <http://example.org/>

:S { :p { :q . } }

and data:

@prefix :      <http://example.org/> .

:a      :p      :b .
:b      :q      1 , 2 .

The shapes map: :a@:S should fail but it passes with the message:

Node <http://example.org/b> matched empty shape

Example: https://tinyurl.com/y2frpzyh