Worksheet error on import statement Follow

With following worksheet content

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import scala.concurrent.Future
import scala.concurrent.Await
import scala.concurrent.duration._

import scala.concurrent.ExecutionContext.Implicits.global

val f = Future { "Hello!"}
println(Await.ready(f, 1.minute))

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I get import errors. Not sure why the unused import error is being reported

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/home/user/.IntelliJIdea2017.3/config/scratches/scratch_15.scala
Error:Error:line (13)Unused import
println(MacroPrinter211.printImportInfo({import scala.concurrent.Future;}))
^
Error:Error:line (15)Unused import
println(MacroPrinter211.printImportInfo({import scala.concurrent.Await;}))
^
Error:Error:line (17)Unused import
println(MacroPrinter211.printImportInfo({import scala.concurrent.duration._;}))
^
Error:Error:line (20)Unused import
println(MacroPrinter211.printImportInfo({import scala.concurrent.ExecutionContext.Implicits.global;}))
^

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This project uses Scala 2.11, 

IntelliJ IDEA 2017.3.4 (Ultimate Edition)
Build #IU-173.4548.28, built on January 30, 2018
JRE: 1.8.0_152-release-1024-b11 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Linux 3.13.0-135-generic