The ZILCH compiler contains the following function:
The line <==? .Y '<>> <PUT .X 1 0> replaces an empty arg <> with 0.
ZILF evals <==? .Y '<>> to #FALSE () what the original MDL interpreter evals to T.
New test method:
Note that '<> should not be considered ==? to '()... ZilListBase.ExactlyEquals is where this is implemented for type LIST, so I think the fix here will be to have ZilForm.ExactlyEquals fall back to calling that.
Fixed in 371aefe7edccda9229212ef95a007122baaa9d44.