#620 "APPLY [ [] [unknown] ] []" leaks memory

[David Costanzo]

If APPLY attempts to run a "named slot template" instruction list and it has an unknown procedure, FMSLogo leaks memory.

I have reproduced this as far back as FMSLogo 6.11.0. In FMSLogo 6.10.1, the leak is not reproducible. A leak is reproducible in MSWLogo 6.5b, but I suspect that's a different memory leak that was fixed before FMSLogo 6.10.0.

How Reproducible:
Every Time

Steps to Reproduce:

SHOW NODES
REPEAT 1000 [ CATCH "error (LIST "APPLY (LIST [] (LIST "unknown) ) [] ) ]
SHOW NODES

What Happens:
The first item in the second NODES printout is several thousand larger than the first item in the first NODES printout

Expected Result:
The first item in the second NODES printout is about the same (within a hundred) of the first item in the first NODES printout.

[David Costanzo]

The bug is not limited to an unknown procedure, it seems like any "named slot template" instruction will cause it. For example, this also reproduces the leak:

SHOW NODES
REPEAT 1000 [ APPLY (LIST [] (LIST "IGNORE 1) ) [] ]
SHOW NODES

At first glance of the leaked nodes, it looks the node representing the anonymous function is leaked because the "treeification" creates a circular reference that is only broken if the node is explicitly untreeified.

In looking at CHANGELOG.TXT for version 6.11.0, I don't see anything that could have introduced this.