#63 Constraint error navigating n:1 from (null)

[Simon Wright]

If navigating a *:1 association starting from a null handle, null is returned. Trying the same with a 1:n association results in a constraint error, rather than an empty collection.

[Simon Wright]

This report is the wrong way round! Going from a null single to the many results in an empty collection, while going from a null many to the single results in Constraint_Error.

[Simon Wright]

Fixed in Mercurial r0e4361e85c1a.