Solutionunvalidated
it turns out that "synthesized three-way comparison" is used to compare each individual class member in a `=default`ed `operator`. Tension: And `T` is shared across all members. Outcome: the synthesized three-way comparison happens twice: first for `a = m.x, b = n.x`, then for `a = m.y, b = n.y`.
afa9881a-1ab2-4e41-9622-5dc899d2cc77
it turns out that "synthesized three-way comparison" is used to compare each individual class member in a =defaulted operator. Tension: And T is shared across all members. Outcome: the synthesized three-way comparison happens twice: first for a = m.x, b = n.x, then for a = m.y, b = n.y.