The problem is that the new test itself fails with:

  ERROR: compiler.test: case-lambda: zero clauses - arguments: ((wrong-number-of-args "eval" "Wrong number of arguments" () #f))

and then a number of tests in tree-il.test fail because they were
assuming the previous behavior for zero-clause ‘case-lambda’.

In addition, this patch uses the Guilish ‘wrong-number-of-args’
exception, not the R6RS one.  This is consistent, but it means that the
R6RS layer would have to convert exceptions again.

Thoughts?

Thanks,
Ludo’.