diff --git a/src/main/scala/scalafix/sbt/ScalafixPlugin.scala b/src/main/scala/scalafix/sbt/ScalafixPlugin.scala
index 7ff1b462..e2ace9a0 100644
--- a/src/main/scala/scalafix/sbt/ScalafixPlugin.scala
+++ b/src/main/scala/scalafix/sbt/ScalafixPlugin.scala
@@ -140,33 +140,47 @@ object ScalafixPlugin extends AutoPlugin {
     )
   }
 
+  private def validateProject(
+      files: Seq[Path],
+      dependencies: Seq[ModuleID],
+      args: ScalafixArguments,
+      ruleNames: Seq[String]
+  ): Seq[String] = {
+    if (files.isEmpty) Nil
+    else {
+      val errors = ListBuffer.empty[String]
+      val isSemanticdb =
+        dependencies.exists(_.name.startsWith("semanticdb-scalac"))
+      if (!isSemanticdb) {
+        val names = ruleNames.mkString(", ")
+        errors +=
+          s"""|The semanticdb-scalac compiler plugin is required to run semantic rules like $names.
+              |To fix this problem for this sbt shell session, run `scalafixEnable` and try again.
+              |To fix this problem permanently for your build, add the following settings to build.sbt:
+              |  addCompilerPlugin(scalafixSemanticdb)
+              |  scalacOptions += "-Yrangepos"
+              |""".stripMargin
+      }
+      val validateError = args.validate()
+      if (validateError.isPresent) {
+        errors += validateError.get().getMessage
+      }
+      errors
+    }
+  }
+
   private def scalafixSemantic(
       ruleNames: Seq[String],
       mainArgs: ScalafixArguments,
       shellArgs: ShellArgs,
       config: Configuration
   ): Def.Initialize[Task[Unit]] = Def.taskDyn {
-    val errors = ListBuffer.empty[String]
-    val isSemanticdb =
-      libraryDependencies.value.exists(_.name.startsWith("semanticdb-scalac"))
-    if (!isSemanticdb) {
-      val names = ruleNames.mkString(", ")
-      errors +=
-        s"""|The semanticdb-scalac compiler plugin is required to run semantic rules like $names.
-            |To fix this problem for this sbt shell session, run `scalafixEnable` and try again.
-            |To fix this problem permanently for your build, add the following settings to build.sbt:
-            |  addCompilerPlugin(scalafixSemanticdb)
-            |  scalacOptions += "-Yrangepos"
-            |""".stripMargin
-    }
+    val dependencies = libraryDependencies.value
+    val files = filesToFix(shellArgs, config).value
     val withScalaArgs = mainArgs
       .withScalaVersion(scalaVersion.value)
       .withScalacOptions(scalacOptions.value.asJava)
-    val validateError = withScalaArgs.validate()
-    if (validateError.isPresent()) {
-      errors += validateError.get().getMessage
-    }
-    val files = filesToFix(shellArgs, config).value
+    val errors = validateProject(files, dependencies, withScalaArgs, ruleNames)
     if (errors.isEmpty) {
       Def.task {
         val args = withScalaArgs.withClasspath(
diff --git a/src/sbt-test/sbt-scalafix/root-validation/build.sbt b/src/sbt-test/sbt-scalafix/root-validation/build.sbt
new file mode 100644
index 00000000..52f9165e
--- /dev/null
+++ b/src/sbt-test/sbt-scalafix/root-validation/build.sbt
@@ -0,0 +1,20 @@
+inThisBuild(
+  List(
+    scalaVersion := "2.12.6",
+  )
+)
+
+lazy val root = project
+  .in(file("."))
+  .aggregate(lib)
+
+lazy val lib = project
+  .in(file("lib"))
+  .settings(
+    addCompilerPlugin(scalafixSemanticdb),
+    scalacOptions ++= List(
+      "-Ywarn-unused",
+      "-Yrangepos"
+    )
+  )
+
diff --git a/src/sbt-test/sbt-scalafix/root-validation/lib/src/main/scala/lib/App.scala b/src/sbt-test/sbt-scalafix/root-validation/lib/src/main/scala/lib/App.scala
new file mode 100644
index 00000000..be4afa42
--- /dev/null
+++ b/src/sbt-test/sbt-scalafix/root-validation/lib/src/main/scala/lib/App.scala
@@ -0,0 +1,6 @@
+package lib
+
+import scala.concurrent.Future
+import scala.util.Success
+
+object App { println(Success(1)) }
diff --git a/src/sbt-test/sbt-scalafix/root-validation/project/plugins.sbt b/src/sbt-test/sbt-scalafix/root-validation/project/plugins.sbt
new file mode 100644
index 00000000..f6f697b2
--- /dev/null
+++ b/src/sbt-test/sbt-scalafix/root-validation/project/plugins.sbt
@@ -0,0 +1,2 @@
+resolvers += Resolver.sonatypeRepo("releases")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % sys.props("plugin.version"))
diff --git a/src/sbt-test/sbt-scalafix/root-validation/project/project/plugins.sbt b/src/sbt-test/sbt-scalafix/root-validation/project/project/plugins.sbt
new file mode 100644
index 00000000..475375b5
--- /dev/null
+++ b/src/sbt-test/sbt-scalafix/root-validation/project/project/plugins.sbt
@@ -0,0 +1 @@
+addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.1.0-M6")
diff --git a/src/sbt-test/sbt-scalafix/root-validation/test b/src/sbt-test/sbt-scalafix/root-validation/test
new file mode 100644
index 00000000..55d8f8c9
--- /dev/null
+++ b/src/sbt-test/sbt-scalafix/root-validation/test
@@ -0,0 +1,3 @@
+-> root/scalafix --check RemoveUnused
+> root/scalafix RemoveUnused
+> root/scalafix --check RemoveUnused