Xcode - Virus BitCoinMiner-AS [Trj]

Hello,

I use Avast antivirus and it finds a virus "MacOS:BitCoinMiner-AS [Trj]"

The virus was detected in Xcode application ("Application/Xcode.app/contents/Framework/libSwiftDispatch/dylib")

and a scan finds it in several systems libraries.

Is this virus dangerous for Mac?

Is it possible that it comes from Xcode download in App Store?

How to prevent from this?

Thank you,

Jean

MacBook Pro (15-inch, 2016)

macOS High Sierra version 10.13.3

Xcode