`po` 给出 `error: <EXPR>:1:1: error: use of unresolved identifier` [英] `po` gives `error: <EXPR>:1:1: error: use of unresolved identifier`

问题描述

我在控制台中的 po 遇到了这个问题，其中尝试输出函数本身可以工作，但输出变量或常量却不行.

I have this problem with po in the console where trying to output a function works in itself, but outputting a variable or constant doesn't.

正如您在此处看到的，虽然您认为 var/let 包含 bar.boy() 的内容，但 Swift 不知何故找不到它...

As you can see here, although you'd think the var/let holds the content of bar.boy(), Swift somehow can't find it...

推荐答案

所以事实证明，过去可能存在一个错误，即当您添加 Swift 文件时，它会添加/询问桥接头，但它不会t 将该行添加到您的项目中

So it turns out there was probably a bug in the past that when you were adding a Swift file it would add/ask a Bridging header, but it wouldn't add that line to your project

SWIFT_OPTIMIZATION_LEVEL = "-Onone";

这意味着你会保持这种状态

which means you'd stay in this state

导致错误:<EXPR>:1:1: error: use of unresolved identifier！

我只能找到它，因为我在项目中移动了文件，当我将 ObjC 文件添加到项目中时，它询问了我关于桥接头的问题(虽然我已经有了一个！)并且幸运地添加了 SWIFT_OPTIMIZATION_LEVEL.人们可以认为这是一个错误，因为默认值是 fastest，但我想这只是过去的一个错误，现在已经修复.

I could only find that out because I moved around files in my project and when I added ObjC files to the project, it asked me about a Bridging header (although I had one already!) and luckily added that SWIFT_OPTIMIZATION_LEVEL. One could consider this is a bug to consider the default value is fastest, but then again I guess this was only a bug in the past and got fixed now.

不过，我现在修复了它可能是一个错误，如果它在发布版本中添加 none.我现在无法测试这个，因为为了测试这个我只有一个 Debug 构建.我将把它作为练习 :) 留给 Apple 的工程师.

Still, I fixed now it might be a bug the other way around, if it add none in the release build. I can't test this right now because for testing this I only had a Debug build. I'll leave that as an exercise :) for Apple's Engineers.

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