Summary: null is null cannot be evaluated at compile time
Keywords: patch, rejects-valid
static assert(null is null);
bug.d(1): Error: static assert (null is null) is not evaluatable at compile t
Whereas the code below compiles fine:
return (null is null);
This also applies to similar kinds of expressions, eg (null is typeid(int)).
The patch for this relies on my patch for 1524, otherwise you get an ICE with
"null is typeid(int)".