Fix a source-compatibility bug in #20658.
Fix a source-compatibility bug in #20658.

Test is in #20629.

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