如何获取有关“功能”标志警告的更多信息？ [英] How to get more information about 'feature' flag warning?

问题描述

使用Play2编译应用程序时，有时这些消息会出现在我的终端上：

When compiling an application with Play2, sometimes these kind of message appears on my terminal :

[info]编译1个Scala源代码到〜/ target / scala-2.10 / classes ...

[警告]有1个功能警告;重新运行-feature以获取详细信息

[警告]发现一个警告

[成功]编译为1s

[info] Compiling 1 Scala source to ~/target/scala-2.10/classes...
[warn] there were 1 feature warnings; re-run with -feature for details
[warn] one warning found
[success] Compiled in 1s

如何获得有关这些警告的更多信息？它必须是sbt的选项，但我不知道在哪里搜索...

How can I get more information about those warning? It must be an option of sbt but I have no idea where to search...

推荐答案

要查看您需要的确切消息在你的sbt构建定义文件中添加feature标志：

To see the exact message you need to add "feature" flag in your sbt build definition file:

scalacOptions ++= Seq("-feature")

为什么？ Scala 2.10不仅引入了新功能，而且还重新调整了旧功能 - 一些最强大的scala功能是隐藏的，因为它们应该被用尽：有时它们被误用了。这就是出现 SIP-18 的原因。从现在开始，要访问动态，更高种类，存在类型以及其他一些必须明确启用它们的东西。

Why? Scala 2.10 not only introduced new features, but also reshuffled older ones -- some of the most powerful scala features were hidden because they should be used with great responsibility: sometimes they were used mistakingly. That is why SIP-18 has arised. From now on, to access dynamics, higher kinds, existential types and some other things you have to explicitly enable them.

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