Allow nullptr as output of ASTGen
Allow nullptr as output of ASTGen

gribozavr/swift,benlangmuir/swift,atrick/swift,karwa/swift,hooman/swift,tkremenek/swift,sschiau/swift,parkera/swift,nathawes/swift,nathawes/swift,devincoughlin/swift,aschwaighofer/swift,nathawes/swift,hooman/swift,atrick/swift,karwa/swift,devincoughlin/swift,hooman/swift,glessard/swift,apple/swift,JGiola/swift,JGiola/swift,tkremenek/swift,roambotics/swift,karwa/swift,apple/swift,roambotics/swift,jmgc/swift,stephentyrone/swift,parkera/swift,airspeedswift/swift,gregomni/swift,rudkx/swift,stephentyrone/swift,gribozavr/swift,benlangmuir/swift,tkremenek/swift,ahoppen/swift,glessard/swift,roambotics/swift,nathawes/swift,sschiau/swift,jckarter/swift,harlanhaskins/swift,hooman/swift,lorentey/swift,jmgc/swift,ahoppen/swift,karwa/swift,apple/swift,atrick/swift,gregomni/swift,devincoughlin/swift,parkera/swift,allevato/swift,JGiola/swift,stephentyrone/swift,nathawes/swift,apple/swift,lorentey/swift,rudkx/swift,CodaFi/swift,parkera/swift,gribozavr/swift,stephentyrone/swift,karwa/swift,airspeedswift/swift,nathawes/swift,JGiola/swift,apple/swift,JGiola/swift,devincoughlin/swift,aschwaighofer/swift,stephentyrone/swift,benlangmuir/swift,sschiau/swift,JGiola/swift,glessard/swift,lorentey/swift,CodaFi/swift,sschiau/swift,jckarter/swift,xwu/swift,jmgc/swift,karwa/swift,allevato/swift,lorentey/swift,jckarter/swift,allevato/swift,rudkx/swift,lorentey/swift,parkera/swift,stephentyrone/swift,rudkx/swift,aschwaighofer/swift,xwu/swift,gregomni/swift,gribozavr/swift,CodaFi/swift,gregomni/swift,airspeedswift/swift,aschwaighofer/swift,glessard/swift,jckarter/swift,airspeedswift/swift,sschiau/swift,hooman/swift,jckarter/swift,allevato/swift,lorentey/swift,xwu/swift,harlanhaskins/swift,parkera/swift,CodaFi/swift,rudkx/swift,atrick/swift,harlanhaskins/swift,gribozavr/swift,roambotics/swift,lorentey/swift,tkremenek/swift,allevato/swift,jckarter/swift,gribozavr/swift,airspeedswift/swift,ahoppen/swift,sschiau/swift,xwu/swift,harlanhaskins/swift,xwu/swift,xwu/swift,atrick/swift,jmgc/swift,jmgc/swift,harlanhaskins/swift,hooman/swift,sschiau/swift,gribozavr/swift,benlangmuir/swift,roambotics/swift,CodaFi/swift,jckarter/swift,aschwaighofer/swift,gregomni/swift,stephentyrone/swift,benlangmuir/swift,devincoughlin/swift,gregomni/swift,nathawes/swift,rudkx/swift,airspeedswift/swift,atrick/swift,karwa/swift,glessard/swift,devincoughlin/swift,tkremenek/swift,devincoughlin/swift,aschwaighofer/swift,allevato/swift,CodaFi/swift,jmgc/swift,harlanhaskins/swift,tkremenek/swift,gribozavr/swift,allevato/swift,sschiau/swift,jmgc/swift,ahoppen/swift,lorentey/swift,CodaFi/swift,apple/swift,roambotics/swift,xwu/swift,ahoppen/swift,harlanhaskins/swift,aschwaighofer/swift,karwa/swift,glessard/swift,devincoughlin/swift,tkremenek/swift,ahoppen/swift,hooman/swift,parkera/swift,parkera/swift,airspeedswift/swift,benlangmuir/swift