bind e'' = exprToWeakExpr χ' e (snd evars_ite)
; return [(sac_altcon sac, vec2list (fst evars_ite), nil, (map (@snd _ _) exprvars), e'')]
| T_Branch b1 b2 => bind b1' = caseBranches b1
bind e'' = exprToWeakExpr χ' e (snd evars_ite)
; return [(sac_altcon sac, vec2list (fst evars_ite), nil, (map (@snd _ _) exprvars), e'')]
| T_Branch b1 b2 => bind b1' = caseBranches b1