Is dereferencing invalid pointers legal if no lvalue-to-rvalue conversion occurs

Question

Try as I might, the closest answer I\'ve seen is this, with two completely opposing answers(!)

The question is simple, is this legal?

auto p = reinterpre         


        

Answer 1

[basic.compound] says:

Every value of pointer type is one of the following:

• a pointer to an object or function (the pointer is said to point to the object or function), or
• a pointer past the end of an object ([expr.add]), or
• the null pointer value ([conv.ptr]) for that type, or
• an invalid pointer value.

By the process of elimination we can deduce that p is an invalid pointer value.

[basic.stc] says:

Indirection through an invalid pointer value and passing an invalid pointer value to a deallocation function have undefined behavior. Any other use of an invalid pointer value has implementation-defined behavior.

As indirection operator is said to perform indirection by [expr.unary.op], I would say, that expression *p causes UB no matter if the result is used or not.