Test code 1:
---------------------------
class K {}
auto f(bool b) {
    if (b)
        return new K;
    else
        return null;
}
---------------------------
x.d(6): Error: mismatched function return type inference of void* and x.K
---------------------------



Test code 2:
---------------------------
auto f(bool b) {
    if (b)
        return new int;
    else
        return null;
}
---------------------------
x.d(5): Error: mismatched function return type inference of void* and int*
---------------------------



DMD should know that 'null' is a valid value for any reference types.

A workaround is to give an exact type, e.g.
---------------------------
auto f(bool b) {
    if (b)
        return new int; // or new K;
    else {
        typeof(return) n = null;
        return n;
    }
}
---------------------------
but this should not be necessary.


(Perhaps the D spec should give a specific type e.g. 'nullptr_t' for 'null'?)