-emit-sil で
 %17 = function_ref @_TFs15_arrayForceCastu0_rFGSax_GSaq__ : $@convention(thin) <τ_0_0, τ_0_1> (@owned Array<τ_0_0>) -> @owned Array<τ_0_1>, loc "test.swift":7:27, scope 21 // user: %18 %18 = apply %17<Cat, Animal>(%14) : $@convention(thin) <τ_0_0, τ_0_1> (@owned Array<τ_0_0>) -> @owned Array<τ_0_1>, loc "test.swift":7:27, scope 21 // user: %19