title: SBT - Always coming up with unresolved dependency error
body: <p>I've been trying to modify the <a href="https://github.com/VirenMohindra/Fratboi" rel="nofollow noreferrer">Fratboi</a> language (which itself is based on the <a href="https://github.com/lhartikk/ArnoldC" rel="nofollow noreferrer">ArnoldC</a> language), and I can't seem to get either one to build, even when I've made no modifications to the source code. </p>
  
  <p>I've been following the instructions in the Fratboi repository, but can't seem to actually compile the language into the handy .jar file that you're supposed to use when running the language. </p>
  
  <p>This is the error:</p>
  
  <pre><code>sbt compile
  [info] Loading settings from plugins.sbt ...
  [info] Loading project definition from /home/user/workspace/Fratboi/project
  [info] Updating {file:/home/user/workspace/Fratboi/project/}fratboi-build...
  [warn]  module not found: com.github.mpeltonen#sbt-idea;1.6.0
  [warn] ==== typesafe-ivy-releases: tried
  [warn]   https://repo.typesafe.com/typesafe/ivy-releases/com.github.mpeltonen/sbt-idea/scala_2.12/sbt_1.0//1.6.0/ivys/ivy.xml
  [warn] ==== sbt-plugin-releases: tried
  [warn]   https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/com.github.mpeltonen/sbt-idea/    scala_2.12/sbt_1.0//1.6.0/ivys/ivy.xml
  [warn] ==== local: tried
  [warn]   /home/user/.ivy2/local/com.github.mpeltonen/sbt-idea/scala_2.12/sbt_1.0//1.6.0/ivys/ivy.xml
  [warn] ==== public: tried
  [warn]   https://repo1.maven.org/maven2/com/github/mpeltonen/sbt-idea_2.12_1.0/1.6.0/sbt-    idea-1.6.0.pom
  [warn] ==== local-preloaded-ivy: tried
  [warn]   /home/user/.sbt/preloaded/com.github.mpeltonen/sbt-idea/1.6.0/ivys/ivy.xml
  [warn] ==== local-preloaded: tried
  [warn]   file:////home/user/.sbt/preloaded/com/github/mpeltonen/sbt-idea_2.12_1.0/1.6.0/sbt-idea-1.6.0.pom
  [warn]  module not found: com.eed3si9n#sbt-assembly;0.14.1
  [warn] ==== typesafe-ivy-releases: tried
  [warn]   https://repo.typesafe.com/typesafe/ivy-releases/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0//0.14.1/ivys/ivy.xml
  [warn] ==== sbt-plugin-releases: tried
  [warn]   https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/com.eed3si9n/sbt-assembly/    scala_2.12/sbt_1.0//0.14.1/ivys/ivy.xml
  [warn] ==== local: tried
  [warn]   /home/user/.ivy2/local/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0//0.14.1/ivys/    ivy.xml
  [warn] ==== public: tried
  [warn]   https://repo1.maven.org/maven2/com/eed3si9n/sbt-assembly_2.12_1.0/0.14.1/sbt-    assembly-0.14.1.pom
  [warn] ==== local-preloaded-ivy: tried
  [warn]   /home/user/.sbt/preloaded/com.eed3si9n/sbt-assembly/0.14.1/ivys/ivy.xml
  [warn] ==== local-preloaded: tried
  [warn]   file:////home/user/.sbt/preloaded/com/eed3si9n/sbt-assembly_2.12_1.0/0.14.1/sbt-    assembly-0.14.1.pom
  [warn]  ::::::::::::::::::::::::::::::::::::::::::::::
  [warn]  ::          UNRESOLVED DEPENDENCIES         ::
  [warn]  ::::::::::::::::::::::::::::::::::::::::::::::
  [warn]  :: com.github.mpeltonen#sbt-idea;1.6.0: not found
  [warn]  :: com.eed3si9n#sbt-assembly;0.14.1: not found
  [warn]  ::::::::::::::::::::::::::::::::::::::::::::::
  [warn] 
  [warn]  Note: Some unresolved dependencies have extra attributes.  Check that these     dependencies exist with the requested attributes.
  [warn]      com.github.mpeltonen:sbt-idea:1.6.0 (scalaVersion=2.12, sbtVersion=1.0)
  [warn]      com.eed3si9n:sbt-assembly:0.14.1 (scalaVersion=2.12, sbtVersion=1.0)
  [warn] 
  [warn]  Note: Unresolved dependencies path:
  [warn]      com.github.mpeltonen:sbt-idea:1.6.0 (scalaVersion=2.12, sbtVersion=1.0) (/    home/user/workspace/Fratboi/project/plugins.sbt#L1-2)
  [warn]        +- default:fratboi-build:0.1-SNAPSHOT (scalaVersion=2.12, sbtVersion=1.0)
  [warn]      com.eed3si9n:sbt-assembly:0.14.1 (scalaVersion=2.12, sbtVersion=1.0) (/home/user/workspace/Fratboi/project/plugins.sbt#L3-4)
  [warn]        +- default:fratboi-build:0.1-SNAPSHOT (scalaVersion=2.12, sbtVersion=1.0)
  [error] sbt.librarymanagement.ResolveException: unresolved dependency: com.github.mpeltonen#sbt-idea;1.6.0: not found
  [error] unresolved dependency: com.eed3si9n#sbt-assembly;0.14.1: not found
  [error]     at sbt.internal.librarymanagement.IvyActions$.resolveAndRetrieve        (IvyActions.scala:331)
  [error]     at sbt.internal.librarymanagement.IvyActions$.$anonfun$updateEither$1    (IvyActions.scala:205)
  [error]     at sbt.internal.librarymanagement.IvySbt$Module.$anonfun$withModule$1    (Ivy.scala:229)
  [error]     at sbt.internal.librarymanagement.IvySbt.$anonfun$withIvy$1(Ivy.scala:190)
  [error]     at sbt.internal.librarymanagement.IvySbt.sbt$internal$librarymanagement$IvySbt$    $action$1(Ivy.scala:70)
  [error]     at sbt.internal.librarymanagement.IvySbt$$anon$3.call(Ivy.scala:77)
  [error]     at xsbt.boot.Locks$GlobalLock.withChannel$1(Locks.scala:93)
  [error]     at xsbt.boot.Locks$GlobalLock.xsbt$boot$Locks$GlobalLock$$withChannelRetries$1    (Locks.scala:78)
  [error]     at xsbt.boot.Locks$GlobalLock$$anonfun$withFileLock$1.apply(Locks.scala:97)
  [error]     at xsbt.boot.Using$.withResource(Using.scala:10)
  [error]     at xsbt.boot.Using$.apply(Using.scala:9)
  [error]     at xsbt.boot.Locks$GlobalLock.ignoringDeadlockAvoided(Locks.scala:58)
  [error]     at xsbt.boot.Locks$GlobalLock.withLock(Locks.scala:48)
  [error]     at xsbt.boot.Locks$.apply0(Locks.scala:31)
  [error]     at xsbt.boot.Locks$.apply(Locks.scala:28)
  [error]     at sbt.internal.librarymanagement.IvySbt.withDefaultLogger(Ivy.scala:77)
  [error]     at sbt.internal.librarymanagement.IvySbt.withIvy(Ivy.scala:185)
  [error]     at sbt.internal.librarymanagement.IvySbt.withIvy(Ivy.scala:182)
  [error]     at sbt.internal.librarymanagement.IvySbt$Module.withModule(Ivy.scala:228)
  [error]     at sbt.internal.librarymanagement.IvyActions$.updateEither(IvyActions.scala:190)
  [error]     at sbt.librarymanagement.ivy.IvyDependencyResolution.update    (IvyDependencyResolution.scala:20)
  [error]     at sbt.librarymanagement.DependencyResolution.update(DependencyResolution.scala:56)
  [error]     at sbt.internal.LibraryManagement$.resolve$1(LibraryManagement.scala:38)
  [error]     at sbt.internal.LibraryManagement$.$anonfun$cachedUpdate$12    (LibraryManagement.scala:91)
  [error]     at sbt.util.Tracked$.$anonfun$lastOutput$1(Tracked.scala:64)
  [error]     at sbt.internal.LibraryManagement$.$anonfun$cachedUpdate$19    (LibraryManagement.scala:104)
  [error]     at scala.util.control.Exception$Catch.apply(Exception.scala:224)
  [error]     at sbt.internal.LibraryManagement$.$anonfun$cachedUpdate$11    (LibraryManagement.scala:104)
  [error]     at sbt.internal.LibraryManagement$.$anonfun$cachedUpdate$11$adapted    (LibraryManagement.scala:87)
  [error]     at sbt.util.Tracked$.$anonfun$inputChanged$1(Tracked.scala:141)
  [error]     at sbt.internal.LibraryManagement$.cachedUpdate(LibraryManagement.scala:118)
  [error]     at sbt.Classpaths$.$anonfun$updateTask$5(Defaults.scala:2313)
  [error]     at scala.Function1.$anonfun$compose$1(Function1.scala:44)
  [error]     at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:42)
  [error]     at sbt.std.Transform$$anon$4.work(System.scala:64)
  [error]     at sbt.Execute.$anonfun$submit$2(Execute.scala:257)
  [error]     at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
  [error]     at sbt.Execute.work(Execute.scala:266)    
  [error]     at sbt.Execute.$anonfun$submit$1(Execute.s    cala:257)
  [error]     at sbt.ConcurrentRestrictions$$anon$4.$ano    nfun$submitValid$1    (ConcurrentRestrictions.scala:167)    
  [error]     at sbt.CompletionService$$anon$2.call(CompletionService.scala:32)
  [error]     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
  [error]     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
  [error]     at java.util.concurrent.FutureTask.run(FutureTask.java:266)    
  [error]     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPool        Executor.java:1149)
  [error]     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
  [error]     at java.lang.Thread.run(Thread.java:748)
  [error] (*:update) sbt.librarymanagement.ResolveException: unresolved dependency:     com.github.mpeltonen#sbt-idea;1.6.0: not found
  [error] unresolved dependency: com.eed3si9n#sbt-assembly;0.14.1: not found
  Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? q
  </code></pre>
  
  <p>Thanks for any help. </p>