self.can_coerce(arm_ty, ret_ty)
&& prior_arm.map_or(true, |(_, ty, _)| self.can_coerce(ty, ret_ty))
// The match arms need to unify for the case of `impl Trait`.
self.can_coerce(arm_ty, ret_ty)
&& prior_arm.map_or(true, |(_, ty, _)| self.can_coerce(ty, ret_ty))
// The match arms need to unify for the case of `impl Trait`.