为什么我无法将地址运算符（＆）应用于函数直接返回值[重复]

Question

This question already has an answer here:

• How to get the pointer of return value from function call? 2 answers

I don't get why the following code snippet isn't compiling. The compiler states:

cannot take the address of getAString()

The code:

func getAStringPointer() *string {
    return &getAString()
}

func getAString() string {
    return ""
}

But, storing the results of the function in auxliary variable and return the address of that variable the compiler behaves OK.

func getAStringPointer() *string {
    var aString = getAString()
    return &aString
}

func getAString() string {
    return ""
}

</div>

Answer 1

You can't apply & to a value like that (unless it's a composite literal). From the spec:

For an operand x of type T, the address operation &x generates a pointer of type *T to x. The operand must be addressable, that is, either a variable, pointer indirection, or slice indexing operation; or a field selector of an addressable struct operand; or an array indexing operation of an addressable array. As an exception to the addressability requirement, x may also be a (possibly parenthesized) composite literal. If the evaluation of x would cause a run-time panic, then the evaluation of &x does too.