为什么将`const`修饰符应用于保存结构值的变量会使结构值不可变？

Question

struct S { string s; }

void method() 
{
    const S s = { "s" };
    s.s = "l"; // Error
}

I can't understand why a compile-error is being generated here. From my understanding, making a struct-referencing variable const should make the variable itself immutable (only s = { "m" } after s initialization should generate error), not the structure itself (so ss = "l" should pass OK). Why const makes both the variable and the struct immutable?

Answer 1

It's not "a variable referencing a struct instance". There's no indirection. The value of s is a struct S , which includes all of its fields.