The presence of a function prevents another function from running

[ngeiswei]

What is the problem?

The presence of a function, foo, prevents another function, bar, from running properly, apparently because one of the arguments of bar unifies with the definition of foo.

How to reproduce it?

Run the following metta file (via metta.py)

;; Define foo
(= (foo $x) $x)             ; prevents bar from running properly

;; Define bar
(: bar (-> Atom Atom Atom))
(= (bar $query $rule)
   (let* (((: $ructor (-> $premise $conclusion)) $rule)
          ((: ($ructor $proof) $conclusion) $query)
          ((: $proof $premise) (: a A)))
          $query))

;; Test bar
!(bar (: ($f a) B) (: f (-> A B)))

What should normally be expected?

[(: (f a) B)]

What is output instead?

[]

Remark

If the definition of foo is removed then the output is the expected one.

[vsbogd]

Looks like it is a duplicate of #242 , closing as now it works as expected.