[m-rev.] for review: Fix abstract equivalence types.

[Dirk Ziegemeyer]

Is the abstract type definition of term.var as

:- type var(T)
    --->    var(int).

a workaround for Mantis bug 411 and could this now be defined as

:- type var(T) == int.

instead?

Dirk


> Am 20.08.2017 um 03:21 schrieb Peter Wang <novalazy at gmail.com>:
> 
> Fix Mantis bug 411. When an abstract type that is defined as equivalent
> to another type is imported into another module, the other module would
> see through the equivalence, making the abstract type not abstract at all.