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c++rvalue-referencevalue-categories

Why is a named rvalue reference an lvalue expression?

I know that a named reference is an lvalue:

int x = 1;
int& ref1 = x;
int&& ref2 = std::move(x);

I've read the explanation — that is because we can take the address of those ref1 and ref2.

But when we take the address of a reference we actually take the address of the referenced object, don't we? So this explanation doesn't seem to be correct.

So why a named reference is an lvalue?

Solution

  • Per [expr.prim.id.unqual] (8.1.4.1 Unqualified names):

    [...] The expression is an lvalue if the entity is a function, variable, or data member and a prvalue otherwise; it is a bit-field if the identifier designates a bit-field ([dcl.struct.bind]).

    Per [basic]/6:

    A variable is introduced by the declaration of a reference other than a non-static data member or of an object. The variable's name, if any, denotes the reference or object.

    The declaration

    int&& ref2 = std::move(x);

    is a "declaration of a reference other than a non-static data member." Therefore, the entity denoted by ref2 is a variable. So the expression ref2 is an lvalue.