C＃

Question

代码阻止

string c = "Hello", d = "Hello";

Console.WriteLine("c is of Type : {0}, d is of Type : {1} ", c.GetType(),d.GetType());
Console.WriteLine("c==d {0}", object.ReferenceEquals(c, d));
Console.WriteLine("c and d hashCode are equal {0}", 
c.GetHashCode() == d.GetHashCode());

输出

  

c的类型为：System.String，d的类型为：System.String

     

c == d True

     

c和d hashCode等于True

代码阻止

string e = "Hello", f = "Hello";

e += " world";
f += " world";

Console.WriteLine("e is of Type : {0}, f is of Type : {1} ", c.GetType(),d.GetType());
Console.WriteLine("e==f {0}", object.ReferenceEquals(e, f));
Console.WriteLine("e and d hashCode are equal {0}", e.GetHashCode() == f.GetHashCode());

输出

  

e的类型为：System.String，f的类型为：System.String

     

e == f False

     

e和f hashCode等于True

问题

Two different “strings” are the same object instance?

提到编译器已经过优化，它会自动引用相同的string，这与变量c和d相关。

但是对于变量e和f，它应该指向相同的string，因为e和f会重新分配给新+=我们尝试对string进行stings操作时的参考（f是不可变的），

但是根据上面的答案链接，变量e应该已经分配给/opt/gitlab/embedded/service/gitlab-shell/hooks/的引用，但根据输出，这两个变量被赋予了新的引用。为什么这样？