should we support Cilk's function-call spawn in addition to statement spawn?

[nelsc]

Presumably we could support this when "_Task_parallel _Spawn" is not immediately followed by a left brace -- a little subtle, but perhaps not too subtle.

[nelsc]

The nice things about spawning the execution of a called function is that there are built-in rules for "capturing" (a.k.a. passing parameters), and without access to the local variables of the calling function, opportunities for writing racy code are less.