> Given:
>
> int main() {
> union U { int i; char c; };
> U u{.i=1};
>
> char c1 = (char&)u;
> char c2 = (char&)u.i;
> char c3 = u.c;
> return c1 + c2 + c3;
> }
>
> c1, c2, and c3 are obviously equivalent here. If there's wording to suggest otherwise, that's a wording defect.

c1 and c2 are equivalent to c3 (and each other), which means UB due to dead object access for all 3 cases.