Guards͕͋͛ΒΕΔ w ͲͪΒίϯύΠϥʹܕΛ໌ࣔ͢Δͷ w Assert Signaturesɺ੍ޚϑϩʔղੳͷͨΊʹܕΛද໌͢ΔͷͰɺUser defined Type Guardsɺܕਪͷ֦ு w ࡶʹݴ͏ͱΓͷҧ͍ User defined Type GuardsBooleanɺAssert Signaturesܕද໌·ͨྫ֎ͷεϩʔ 16
Level AwaitͳͲͷศར༷৽ نͪΖΜɺطଘͷίʔυΛ͘ॻ͖͢͜ͱ͕Ͱ͖ͦ͏Ͱ͢ w Assert SignaturesType Guardͱಉ͘͡ܕड़ޠͳͷͰॊೈੑͱҾ͖͑ʹܕ ҆શΛࣗͨͪͰ୲อ͢Δ͜ͱʹͳΓ·͢ w Recursive Type ReferencesͲ͏Ͱ͠ΐ͏ʢඞཁͳ໘ʹૺ۰ͨ͜͠ͱ͕ͳ ͍ʣ 17