import core.memory;
import core.stdc.stdlib : malloc, free;
import core.lifetime : emplace;

T NEW(T, Args...)(auto ref Args args) /*@nogc*/ if (is(T == class)) {
    enum size = __traits(classInstanceSize, T);
    void* mem = malloc(size);
    scope(failure) free(mem);
    return mem !is null ? emplace!T(mem[0..size], args) : null;
}
void FREE(T)(ref T obj) @nogc if (is(T == class)) {
    auto mem = cast(void*) obj;
    scope(exit) free(mem);
    destroy(obj);//这里不行,总是说有问题.
    obj = null;
}

extern(C++) class Foo {//加上这个extern(C++)同样如此.
    ~this() @nogc {}
}//仍有编译问题

void main() {
    auto foo = NEW!Foo;
    FREE(foo);
}