swift - 编译失败 : argument type 'Character' does not conform to expected type 'ExpressibleByStringLiteral'

Question

我有这个代码:

private func validate(text: String) -> String {
    let acceptableChar: Set<Character> = ["0", "9", "8", "7", "6", "5", "4", "3", "2", "1", "."]
//    let acceptableChar: [Character] = ["0", "9", "8", "7", "6", "5", "4", "3", "2", "1", "."]

    var clearText = text
    clearText.removeAll(where: { !acceptableChar.contains($0) })
    return clearText
}

在所有设备(iPhone、iPad 和 Mac)的 Xcode 11.3.1 (11C504) 中运行良好，但在 PreviewProvider 中，我有这个错误:

    Compiling failed: argument type 'Character' does not conform to expected type 'ExpressibleByStringLiteral'
.....


    error: argument type 'Character' does not conform to expected type 'ExpressibleByStringLiteral'
        let acceptableChar: Set<Character> = [__designTimeString("#2775.[2].[0].value.[0].[0].value", fallback: "0"), __designTimeString("#2775.[2].[0].value.[1].[0].value", fallback: "9"), __designTimeString("#2775.[2].[0].value.[2].[0].value", fallback: "8"), __designTimeString("#2775.[2].[0].value.[3].[0].value", fallback: "7"), __designTimeString("#2775.[2].[0].value.[4].[0].value", fallback: "6"), __designTimeString("#2775.[2].[0].value.[5].[0].value", fallback: "5"), __designTimeString("#2775.[2].[0].value.[6].[0].value", fallback: "4"), __designTimeString("#2775.[2].[0].value.[7].[0].value", fallback: "3"), __designTimeString("#2775.[2].[0].value.[8].[0].value", fallback: "2"), __designTimeString("#2775.[2].[0].value.[9].[0].value", fallback: "1"), __designTimeString("#2775.[2].[0].value.[10].[0].value", fallback: ".")]

有人知道如何修改 private func validate(text: String) -> String { 来消除这个错误吗？

Answer 1

使用下面的声明

let acceptableChar = Set<Character>(arrayLiteral: 
     "0", "9", "8", "7", "6", "5", "4", "3", "2", "1", ".")

测试并使用 Xcode 11.2/iOS 13.2