void main returning int - why compiles?

[bearophile]

Manfred Nowak:

> _and_ foo() is not marked to have no side effects.

You are right, thank you for the quotation. So I have updated this, because it's not a bug:
http://d.puremagic.com/issues/show_bug.cgi?id=5399

I'm sure there's a rationale behind that special case in the D specs. Is someone able to explain? It looks like an unsafe corner case.

Bye,
bearophile