`try` expressions in paren-free tests

[wcjohnson]

lscdiag

This is probably why try without the colon was allowed in the first place.

It's probably possible to fix this using the same general outline I used to fix the early whiteblock termination problem, but the syntax with the double colons is a bit ugly.

[rattrayalex]

hmm, it also fails with a catch though, as well as with curly braces, so I think it seems like a problem with match parsing, not try?

[wcjohnson]

Those two links aren't set to compiler version 4; it looks like it works with curly braces but not with colons.

[wcjohnson]

Possible fix for this one is live in alpha.13 but it could be a bit sketchy, leaving open for some more testing.