[CodeCompletion] Cleanup typeCheckContextAt()
[CodeCompletion] Cleanup typeCheckContextAt()

There's no need of separate 'Impl' function

allevato/swift,glessard/swift,CodaFi/swift,parkera/swift,gregomni/swift,tkremenek/swift,JGiola/swift,xwu/swift,glessard/swift,gregomni/swift,atrick/swift,ahoppen/swift,benlangmuir/swift,tkremenek/swift,benlangmuir/swift,parkera/swift,jmgc/swift,hooman/swift,xwu/swift,rudkx/swift,jmgc/swift,roambotics/swift,JGiola/swift,glessard/swift,allevato/swift,JGiola/swift,atrick/swift,nathawes/swift,roambotics/swift,hooman/swift,roambotics/swift,roambotics/swift,jmgc/swift,glessard/swift,nathawes/swift,roambotics/swift,parkera/swift,nathawes/swift,rudkx/swift,tkremenek/swift,ahoppen/swift,JGiola/swift,allevato/swift,glessard/swift,jmgc/swift,gregomni/swift,allevato/swift,apple/swift,atrick/swift,CodaFi/swift,parkera/swift,apple/swift,JGiola/swift,apple/swift,apple/swift,benlangmuir/swift,nathawes/swift,benlangmuir/swift,atrick/swift,JGiola/swift,nathawes/swift,ahoppen/swift,hooman/swift,parkera/swift,CodaFi/swift,roambotics/swift,ahoppen/swift,hooman/swift,parkera/swift,nathawes/swift,rudkx/swift,allevato/swift,parkera/swift,gregomni/swift,jmgc/swift,glessard/swift,ahoppen/swift,xwu/swift,tkremenek/swift,tkremenek/swift,CodaFi/swift,ahoppen/swift,CodaFi/swift,gregomni/swift,allevato/swift,benlangmuir/swift,xwu/swift,hooman/swift,nathawes/swift,apple/swift,allevato/swift,atrick/swift,CodaFi/swift,CodaFi/swift,atrick/swift,tkremenek/swift,hooman/swift,xwu/swift,rudkx/swift,hooman/swift,apple/swift,benlangmuir/swift,jmgc/swift,tkremenek/swift,xwu/swift,jmgc/swift,gregomni/swift,parkera/swift,xwu/swift,rudkx/swift,rudkx/swift