Another shot at fixing the issues with (constant) struct literals and their addresses. See DMD2682, #218, #324. The idea is to separate the notion of const from 'this variable can always be replaced with its initializer' in the frontend. To do that, I introduced Declaration::isSameAsInitializer, which is overridden in VarDeclaration to return false for constants that have a struct literal initializer. So {{{ const S s = S(5); void foo() { auto ps = &s; } // is no longer replaced by void foo() { auto ps = &(S(5)); } }}} To make taking the address of a struct constant with a struct-initializer outside of function scope possible, I made sure that AddrExp::optimize doesn't try to run the argument's optimization with WANTinterpret - that'd again replace the constant with a struct literal temporary.

module vararg1;

import tango.stdc.stdarg;

extern(C) int add(int n, ...)
{
    va_list ap=void;
    va_start(ap, n);
    int r;
    for (int i=0; i<n; i++)
        r += va_arg!(int)(ap);
    va_end(ap);
    return r;
}

void main()
{
    int i = add(4, 1,2,3,4);
    assert(i == 10);
}