[TypeJoin] Use isExistentialType() and inheritsFrom() as appropriate.
[TypeJoin] Use isExistentialType() and inheritsFrom() as appropriate.

gribozavr/swift,devincoughlin/swift,practicalswift/swift,CodaFi/swift,sschiau/swift,lorentey/swift,nathawes/swift,danielmartin/swift,practicalswift/swift,devincoughlin/swift,sschiau/swift,CodaFi/swift,alblue/swift,shahmishal/swift,jmgc/swift,gregomni/swift,ahoppen/swift,allevato/swift,alblue/swift,benlangmuir/swift,gregomni/swift,brentdax/swift,CodaFi/swift,danielmartin/swift,devincoughlin/swift,shajrawi/swift,sschiau/swift,austinzheng/swift,atrick/swift,roambotics/swift,lorentey/swift,parkera/swift,stephentyrone/swift,brentdax/swift,parkera/swift,ahoppen/swift,karwa/swift,practicalswift/swift,devincoughlin/swift,atrick/swift,shahmishal/swift,gregomni/swift,xwu/swift,rudkx/swift,jckarter/swift,aschwaighofer/swift,allevato/swift,practicalswift/swift,nathawes/swift,tkremenek/swift,jmgc/swift,shajrawi/swift,CodaFi/swift,jmgc/swift,harlanhaskins/swift,xwu/swift,brentdax/swift,amraboelela/swift,lorentey/swift,roambotics/swift,stephentyrone/swift,apple/swift,sschiau/swift,JGiola/swift,shajrawi/swift,shajrawi/swift,atrick/swift,practicalswift/swift,airspeedswift/swift,karwa/swift,karwa/swift,roambotics/swift,danielmartin/swift,devincoughlin/swift,xedin/swift,airspeedswift/swift,shajrawi/swift,jckarter/swift,amraboelela/swift,JGiola/swift,stephentyrone/swift,jmgc/swift,glessard/swift,gregomni/swift,gribozavr/swift,brentdax/swift,gribozavr/swift,benlangmuir/swift,karwa/swift,parkera/swift,atrick/swift,JGiola/swift,apple/swift,gribozavr/swift,shahmishal/swift,austinzheng/swift,karwa/swift,sschiau/swift,stephentyrone/swift,karwa/swift,tkremenek/swift,lorentey/swift,xwu/swift,lorentey/swift,hooman/swift,shahmishal/swift,alblue/swift,brentdax/swift,harlanhaskins/swift,brentdax/swift,practicalswift/swift,xedin/swift,benlangmuir/swift,danielmartin/swift,alblue/swift,tkremenek/swift,sschiau/swift,hooman/swift,rudkx/swift,JGiola/swift,lorentey/swift,glessard/swift,glessard/swift,practicalswift/swift,gribozavr/swift,rudkx/swift,harlanhaskins/swift,atrick/swift,allevato/swift,aschwaighofer/swift,hooman/swift,danielmartin/swift,jckarter/swift,xwu/swift,allevato/swift,nathawes/swift,tkremenek/swift,brentdax/swift,jmgc/swift,shahmishal/swift,rudkx/swift,stephentyrone/swift,aschwaighofer/swift,devincoughlin/swift,glessard/swift,benlangmuir/swift,jckarter/swift,jmgc/swift,stephentyrone/swift,austinzheng/swift,alblue/swift,jmgc/swift,benlangmuir/swift,hooman/swift,apple/swift,amraboelela/swift,xwu/swift,austinzheng/swift,austinzheng/swift,airspeedswift/swift,harlanhaskins/swift,ahoppen/swift,gribozavr/swift,glessard/swift,parkera/swift,lorentey/swift,parkera/swift,stephentyrone/swift,shajrawi/swift,parkera/swift,benlangmuir/swift,hooman/swift,xedin/swift,rudkx/swift,roambotics/swift,roambotics/swift,gregomni/swift,karwa/swift,parkera/swift,airspeedswift/swift,xedin/swift,lorentey/swift,shahmishal/swift,xedin/swift,xedin/swift,xwu/swift,jckarter/swift,devincoughlin/swift,sschiau/swift,parkera/swift,gregomni/swift,austinzheng/swift,shajrawi/swift,tkremenek/swift,aschwaighofer/swift,hooman/swift,amraboelela/swift,atrick/swift,tkremenek/swift,austinzheng/swift,hooman/swift,apple/swift,CodaFi/swift,xwu/swift,danielmartin/swift,allevato/swift,tkremenek/swift,CodaFi/swift,ahoppen/swift,CodaFi/swift,practicalswift/swift,aschwaighofer/swift,JGiola/swift,harlanhaskins/swift,devincoughlin/swift,apple/swift,airspeedswift/swift,gribozavr/swift,roambotics/swift,alblue/swift,allevato/swift,harlanhaskins/swift,allevato/swift,xedin/swift,aschwaighofer/swift,alblue/swift,gribozavr/swift,apple/swift,danielmartin/swift,airspeedswift/swift,shahmishal/swift,karwa/swift,ahoppen/swift,JGiola/swift,xedin/swift,ahoppen/swift,jckarter/swift,nathawes/swift,nathawes/swift,harlanhaskins/swift,jckarter/swift,amraboelela/swift,glessard/swift,nathawes/swift,amraboelela/swift,airspeedswift/swift,shajrawi/swift,shahmishal/swift,amraboelela/swift,nathawes/swift,sschiau/swift,rudkx/swift,aschwaighofer/swift