Play framework route file compilation warning: local val in method at is never used

Question

On my play app, I have a routes file with routes for public files. Recently I added the -Ywarn-unused compiler flag, and I'm getting some unexpected warnings.

Steps:

activator new testingScalac (choose play-scala from the template list)
Add to build.sbt the flag with scalacOptions ++= Seq("-Ywarn-unused")
Add to the routes file:

GET /favicon.ico controllers.Assets.at(path="/public",file="/images/favicon.ico")

GET /favicon.png controllers.Assets.at(path="/public",file="/images/favicon.png")

GET /robots.txt controllers.Assets.at(path="/public",file="robots.txt")

Now, running sbt compile returns:

$ sbt compile
[info] Loading project definition from /Users/pedrorijo/git/testRepos/testingScalac/project
[info] Set current project to testingScalac (in build file:/Users/pedrorijo/git/testRepos/testingScalac/)
[info] Compiling 4 Scala sources and 1 Java source to /Users/pedrorijo/git/testRepos/testingScalac/target/scala-2.11/classes...
[warn] /Users/pedrorijo/git/testRepos/testingScalac/conf/routes:15: local val in method at is never used
[warn] GET        /favicon.ico            controllers.Assets.at(path="/public",file="/images/favicon.ico")
[warn] /Users/pedrorijo/git/testRepos/testingScalac/conf/routes:16: local val in method at is never used
[warn] GET        /favicon.png            controllers.Assets.at(path="/public",file="/images/favicon.png")
[warn] /Users/pedrorijo/git/testRepos/testingScalac/conf/routes:17: local val in method at is never used
[warn] GET        /robots.txt             controllers.Assets.at(path="/public",file="robots.txt")
[warn] three warnings found
[success] Total time: 10 s, completed Jul 5, 2016 3:11:28 PM

Am I doing something wrong on the routes file, or is it a playframework/compiler bug (I looked in github and couldn't find anything related to this)?

Note: it uses play 2.5.4 but it also happens on play 2.4.x

probably, even if I won't call it a bug, as it "just" raise warning — cchantep, Jul 05 '16 at 14:56
but I do use the fatal-warnings flag, which makes compilation fail with any warning. — pedrorijo91, Jul 05 '16 at 14:57
Anyway, I suggest you to open an issue with a small project that shows the problem. — marcospereira, Jul 06 '16 at 02:14
I have the same warning with play 2.5.15. Do you already have a solutions for this? And what about opening an issue on github? — Gabor, Jun 30 '17 at 08:45
@Gábor I created a bug at the time. just posted an answer with the details — pedrorijo91, Jun 30 '17 at 08:52

score 0 · Accepted Answer · answered Jun 30 '17 at 08:52

0

Created an issue, it seems to be a Play framework problem: https://github.com/playframework/playframework/issues/6302

In the meanwhile a PR has been done that may fix: https://github.com/playframework/playframework/pull/7538

answered Jun 30 '17 at 08:52

pedrorijo91

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Play framework route file compilation warning: local val in method at is never used

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