Value declarations with patterns on the left without variables

[gisellemnr]

There seems to be an inconsistency when it comes to how sml-to-coq handles value declarations without variables on the left.

The following code is parsed, and no Coq code is generated (as expected):

val (2, 3) = (2 + 0, 2 + 1);

However, the following code fails with Fail: Invalid pattern!

val 4 = 2 + 2;