[AST] Don't lose the parent type in setUnderlyingType.
[AST] Don't lose the parent type in setUnderlyingType.

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