❌Argument type 'xxx' does not conform to expected type '_FormatSpecifiable'

這看起來是一個問題，但卻產生兩個錯誤，很奇怪。

另一個錯誤訊息：

❌ Cannot convert value of type 'MyClass' to expected argument type 'String'

❌ Errors

import SwiftUI

struct MyStruct: CustomStringConvertible {
    var description: String { "hello" }
}

class MyClass: CustomStringConvertible {
    var description: String { "hi" }
}


let a = MyStruct()
let b = MyClass()
print("\(a)")        // hello
print("\(b)")        // hi

// ❌ Argument type 'MyStruct' does not conform to
//    expected type '_FormatSpecifiable'
let text1 = Text("\(a)")

// ❌ Cannot convert value of type 'MyClass' to
//    expected argument type 'String'
let text2 = Text("\(b)")

📘 參考

• StackOverflow：Argument type 'xxx' does not conform to expected type '_FormatSpecifiable' ⭐

👥 相關

• SwiftUI > Views and Controls > LocalizedStringKey

• Swift > Standard Library > Basic Behaviors > CustomStringConvertible

• 🔰 String Interpolation