d的可调用

原文

import std.traits : isCallable;

struct MyStruct
{
    auto foo() { return MyStruct(); }

    static if (isCallable!foo)
        pragma(msg, "GOOD");
    else
        pragma(msg, "BAD");
}

import core.stdc.stdio;
extern(C):
void main()
{
    MyStruct a;
}