おおお、ほんとだ・・・。衝突した。 struct Foo { subscript(i: Int) -> Int { return i } func `subscript`(_ i: Int) -> Int { return i + 1 } }

 9> Foo().subscript(42) error: repl.swift:9:1: error: ambiguous use of 'subscript' Foo().subscript(42) ^ repl.swift:2:5: note: found this candidate subscript(i: Int) -> Int { ^ repl.swift:5:10: note: found this candidate func `subscript`(_ i: Int) -> Int { ^

 9> Foo().`subscript`(42) error: repl.swift:9:1: error: ambiguous use of 'subscript' Foo().`subscript`(42) ^ repl.swift:2:5: note: found this candidate subscript(i: Int) -> Int { ^ repl.swift:5:10: note: found this candidate func `subscript`(_ i: Int) -> Int { ^

 9> Foo()[42] error: repl.swift:9:1: error: ambiguous use of 'subscript' Foo()[42] ^ repl.swift:2:5: note: found this candidate subscript(i: Int) -> Int { ^ repl.swift:5:10: note: found this candidate func `subscript`(_ i: Int) -> Int { ^

(edited)