@noreturn property

[Iain Buclaw]

A few standard library functions, such as 'abort' and 'exit', cannot return.
However there is no way in DMD to let the compiler know about this.
Currently in D2, you must either have a 'return' or 'assert(0)' statement at
the end of a function body. It would be nice however if you can give hints to
the compiler to let it know that a function is never going to return.

Example:

@noreturn void fatal()
{
    print("Error");
    exit(1);
}

The 'noreturn' keyword would tell the compiler that 'fatal' cannot return, and
can then optimise without regard to what would happen if 'fatal' ever did
return. This should also allow fatal to be used instead of a return or assert
statement.

Example:

int mycheck(int x)
{
    if (x > 1)
        return OK;
    fatal();
}


Thoughts?