When is it valid to access a pointer to a “dead” object?

Question

First, to clarify, I am not talking about dereferencing invalid pointers!

Consider the following two examples.

Example 1

Answer 1

Example 2 is invalid. The analysis in your question is correct.

Example 1 is valid. A structure type never holds a trap representation, even if one of its members does. This means that structure assignment, on a system where trap representations would cause problems, must be implemented as a bytewise copy, rather than a member-by-member copy.

6.2.6 Representations of types

6.2.6.1 General

6 [...] The value of a structure or union object is never a t rap representation, even though the value of a member of the structure or union object may be a trap representation.