Section OneType.
Variable T : choiceType.
Implicit Types P Q : pred T.
Definition xchoose P exP := sval (@xchoose_subproof T P exP).

Lemma sig2_eqW (vT : eqType) (P : pred T) (lhs rhs : T -> vT) :
(exists2 x, P x & lhs x = rhs x) -> {x | P x & lhs x = rhs x}.