Fix some issues handling rewalks of the same expression when something was found to be invalid.
Fix some issues handling rewalks of the same expression when something was found to be invalid.

Swift SVN r270

IngmarStein/swift,gregomni/swift,airspeedswift/swift,roambotics/swift,milseman/swift,lorentey/swift,MukeshKumarS/Swift,JaSpa/swift,return/swift,tardieu/swift,gmilos/swift,frootloops/swift,devincoughlin/swift,sschiau/swift,JGiola/swift,adrfer/swift,jckarter/swift,natecook1000/swift,calebd/swift,gottesmm/swift,shajrawi/swift,calebd/swift,jtbandes/swift,atrick/swift,brentdax/swift,hughbe/swift,alblue/swift,kusl/swift,harlanhaskins/swift,deyton/swift,kstaring/swift,kstaring/swift,amraboelela/swift,frootloops/swift,djwbrown/swift,tjw/swift,ken0nek/swift,codestergit/swift,Jnosh/swift,nathawes/swift,apple/swift,cbrentharris/swift,kusl/swift,sdulal/swift,frootloops/swift,mightydeveloper/swift,felix91gr/swift,JGiola/swift,return/swift,nathawes/swift,ken0nek/swift,Jnosh/swift,alblue/swift,modocache/swift,calebd/swift,atrick/swift,JGiola/swift,cbrentharris/swift,shajrawi/swift,manavgabhawala/swift,gmilos/swift,hooman/swift,hughbe/swift,tardieu/swift,practicalswift/swift,tjw/swift,jckarter/swift,SwiftAndroid/swift,gottesmm/swift,lorentey/swift,mightydeveloper/swift,glessard/swift,SwiftAndroid/swift,sschiau/swift,danielmartin/swift,kperryua/swift,practicalswift/swift,tjw/swift,danielmartin/swift,KrishMunot/swift,adrfer/swift,hughbe/swift,devincoughlin/swift,emilstahl/swift,lorentey/swift,mightydeveloper/swift,airspeedswift/swift,huonw/swift,Ivacker/swift,ben-ng/swift,amraboelela/swift,IngmarStein/swift,ben-ng/swift,LeoShimonaka/swift,tjw/swift,return/swift,milseman/swift,huonw/swift,xwu/swift,danielmartin/swift,modocache/swift,hughbe/swift,LeoShimonaka/swift,emilstahl/swift,stephentyrone/swift,milseman/swift,parkera/swift,KrishMunot/swift,hooman/swift,jopamer/swift,sdulal/swift,hughbe/swift,ben-ng/swift,jopamer/swift,deyton/swift,swiftix/swift,amraboelela/swift,russbishop/swift,SwiftAndroid/swift,apple/swift,codestergit/swift,CodaFi/swift,gottesmm/swift,dduan/swift,amraboelela/swift,gmilos/swift,hooman/swift,karwa/swift,slavapestov/swift,jopamer/swift,austinzheng/swift,LeoShimonaka/swift,deyton/swift,devincoughlin/swift,harlanhaskins/swift,gribozavr/swift,kperryua/swift,felix91gr/swift,devincoughlin/swift,karwa/swift,MukeshKumarS/Swift,slavapestov/swift,atrick/swift,allevato/swift,kusl/swift,return/swift,johnno1962d/swift,parkera/swift,aschwaighofer/swift,amraboelela/swift,jopamer/swift,uasys/swift,kperryua/swift,brentdax/swift,bitjammer/swift,sschiau/swift,slavapestov/swift,xwu/swift,tinysun212/swift-windows,felix91gr/swift,zisko/swift,xedin/swift,tkremenek/swift,xwu/swift,tardieu/swift,IngmarStein/swift,CodaFi/swift,karwa/swift,SwiftAndroid/swift,shahmishal/swift,xedin/swift,lorentey/swift,kperryua/swift,apple/swift,felix91gr/swift,dduan/swift,tkremenek/swift,deyton/swift,uasys/swift,swiftix/swift,shajrawi/swift,ahoppen/swift,sdulal/swift,nathawes/swift,austinzheng/swift,danielmartin/swift,dduan/swift,jtbandes/swift,zisko/swift,swiftix/swift.old,lorentey/swift,shahmishal/swift,milseman/swift,austinzheng/swift,parkera/swift,adrfer/swift,kstaring/swift,parkera/swift,SwiftAndroid/swift,jmgc/swift,tinysun212/swift-windows,aschwaighofer/swift,sschiau/swift,glessard/swift,khizkhiz/swift,arvedviehweger/swift,emilstahl/swift,IngmarStein/swift,nathawes/swift,apple/swift,milseman/swift,shajrawi/swift,adrfer/swift,harlanhaskins/swift,ben-ng/swift,Ivacker/swift,lorentey/swift,russbishop/swift,manavgabhawala/swift,gribozavr/swift,huonw/swift,frootloops/swift,tardieu/swift,gmilos/swift,felix91gr/swift,swiftix/swift.old,kentya6/swift,tinysun212/swift-windows,benlangmuir/swift,kstaring/swift,karwa/swift,Jnosh/swift,nathawes/swift,kusl/swift,khizkhiz/swift,ken0nek/swift,hughbe/swift,shajrawi/swift,arvedviehweger/swift,gmilos/swift,kentya6/swift,cbrentharris/swift,KrishMunot/swift,russbishop/swift,stephentyrone/swift,russbishop/swift,swiftix/swift.old,deyton/swift,dduan/swift,ahoppen/swift,CodaFi/swift,LeoShimonaka/swift,MukeshKumarS/Swift,return/swift,khizkhiz/swift,austinzheng/swift,KrishMunot/swift,harlanhaskins/swift,practicalswift/swift,alblue/swift,dduan/swift,shahmishal/swift,emilstahl/swift,alblue/swift,bitjammer/swift,shahmishal/swift,arvedviehweger/swift,Jnosh/swift,aschwaighofer/swift,tjw/swift,cbrentharris/swift,KrishMunot/swift,hooman/swift,JGiola/swift,huonw/swift,jtbandes/swift,jmgc/swift,practicalswift/swift,brentdax/swift,xwu/swift,calebd/swift,rudkx/swift,sschiau/swift,swiftix/swift,dreamsxin/swift,johnno1962d/swift,tjw/swift,airspeedswift/swift,cbrentharris/swift,glessard/swift,IngmarStein/swift,swiftix/swift,amraboelela/swift,gmilos/swift,shajrawi/swift,tinysun212/swift-windows,lorentey/swift,tkremenek/swift,gregomni/swift,ben-ng/swift,codestergit/swift,gmilos/swift,glessard/swift,gribozavr/swift,CodaFi/swift,JaSpa/swift,bitjammer/swift,jckarter/swift,JaSpa/swift,mightydeveloper/swift,danielmartin/swift,benlangmuir/swift,alblue/swift,manavgabhawala/swift,johnno1962d/swift,return/swift,huonw/swift,roambotics/swift,xedin/swift,stephentyrone/swift,shahmishal/swift,jopamer/swift,gribozavr/swift,kusl/swift,glessard/swift,frootloops/swift,frootloops/swift,hughbe/swift,allevato/swift,tjw/swift,Ivacker/swift,shajrawi/swift,kusl/swift,OscarSwanros/swift,deyton/swift,shahmishal/swift,rudkx/swift,uasys/swift,ben-ng/swift,bitjammer/swift,Ivacker/swift,cbrentharris/swift,therealbnut/swift,benlangmuir/swift,khizkhiz/swift,huonw/swift,emilstahl/swift,ken0nek/swift,slavapestov/swift,kstaring/swift,nathawes/swift,alblue/swift,xwu/swift,modocache/swift,austinzheng/swift,alblue/swift,gribozavr/swift,OscarSwanros/swift,therealbnut/swift,natecook1000/swift,sdulal/swift,manavgabhawala/swift,emilstahl/swift,khizkhiz/swift,apple/swift,benlangmuir/swift,johnno1962d/swift,kusl/swift,danielmartin/swift,therealbnut/swift,Ivacker/swift,mightydeveloper/swift,ahoppen/swift,stephentyrone/swift,kperryua/swift,gregomni/swift,aschwaighofer/swift,atrick/swift,roambotics/swift,lorentey/swift,milseman/swift,natecook1000/swift,Ivacker/swift,MukeshKumarS/Swift,xedin/swift,OscarSwanros/swift,amraboelela/swift,zisko/swift,rudkx/swift,gregomni/swift,mightydeveloper/swift,cbrentharris/swift,brentdax/swift,uasys/swift,kentya6/swift,arvedviehweger/swift,swiftix/swift.old,slavapestov/swift,gregomni/swift,jckarter/swift,JaSpa/swift,swiftix/swift.old,austinzheng/swift,djwbrown/swift,parkera/swift,devincoughlin/swift,modocache/swift,gottesmm/swift,CodaFi/swift,bitjammer/swift,tinysun212/swift-windows,KrishMunot/swift,practicalswift/swift,russbishop/swift,arvedviehweger/swift,aschwaighofer/swift,swiftix/swift.old,danielmartin/swift,emilstahl/swift,gregomni/swift,tardieu/swift,djwbrown/swift,CodaFi/swift,tardieu/swift,atrick/swift,swiftix/swift.old,tinysun212/swift-windows,devincoughlin/swift,kperryua/swift,russbishop/swift,brentdax/swift,codestergit/swift,hooman/swift,karwa/swift,tkremenek/swift,arvedviehweger/swift,SwiftAndroid/swift,apple/swift,natecook1000/swift,jmgc/swift,xedin/swift,OscarSwanros/swift,kperryua/swift,therealbnut/swift,JGiola/swift,tardieu/swift,milseman/swift,swiftix/swift,therealbnut/swift,gottesmm/swift,jtbandes/swift,djwbrown/swift,calebd/swift,atrick/swift,arvedviehweger/swift,xedin/swift,ken0nek/swift,swiftix/swift.old,LeoShimonaka/swift,stephentyrone/swift,KrishMunot/swift,zisko/swift,JaSpa/swift,felix91gr/swift,practicalswift/swift,dduan/swift,ahoppen/swift,aschwaighofer/swift,airspeedswift/swift,gottesmm/swift,djwbrown/swift,jtbandes/swift,airspeedswift/swift,huonw/swift,shahmishal/swift,MukeshKumarS/Swift,jmgc/swift,slavapestov/swift,harlanhaskins/swift,tkremenek/swift,return/swift,bitjammer/swift,parkera/swift,Jnosh/swift,mightydeveloper/swift,shajrawi/swift,johnno1962d/swift,jmgc/swift,brentdax/swift,parkera/swift,adrfer/swift,tinysun212/swift-windows,Jnosh/swift,kstaring/swift,johnno1962d/swift,dduan/swift,therealbnut/swift,sdulal/swift,dreamsxin/swift,khizkhiz/swift,IngmarStein/swift,codestergit/swift,JaSpa/swift,sdulal/swift,kstaring/swift,roambotics/swift,benlangmuir/swift,ahoppen/swift,manavgabhawala/swift,SwiftAndroid/swift,adrfer/swift,swiftix/swift,nathawes/swift,calebd/swift,jmgc/swift,Ivacker/swift,OscarSwanros/swift,modocache/swift,sschiau/swift,JaSpa/swift,allevato/swift,tkremenek/swift,jmgc/swift,jtbandes/swift,modocache/swift,manavgabhawala/swift,mightydeveloper/swift,jopamer/swift,brentdax/swift,LeoShimonaka/swift,harlanhaskins/swift,practicalswift/swift,ken0nek/swift,uasys/swift,LeoShimonaka/swift,xedin/swift,frootloops/swift,glessard/swift,jtbandes/swift,therealbnut/swift,johnno1962d/swift,allevato/swift,rudkx/swift,kentya6/swift,karwa/swift,deyton/swift,devincoughlin/swift,khizkhiz/swift,sschiau/swift,gribozavr/swift,cbrentharris/swift,kentya6/swift,MukeshKumarS/Swift,natecook1000/swift,sdulal/swift,codestergit/swift,xedin/swift,Ivacker/swift,sdulal/swift,codestergit/swift,kentya6/swift,uasys/swift,jckarter/swift,uasys/swift,modocache/swift,gribozavr/swift,austinzheng/swift,roambotics/swift,ahoppen/swift,stephentyrone/swift,JGiola/swift,jopamer/swift,rudkx/swift,emilstahl/swift,allevato/swift,allevato/swift,tkremenek/swift,airspeedswift/swift,kusl/swift,jckarter/swift,karwa/swift,OscarSwanros/swift,hooman/swift,zisko/swift,stephentyrone/swift,allevato/swift,swiftix/swift,slavapestov/swift,bitjammer/swift,practicalswift/swift,ben-ng/swift,MukeshKumarS/Swift,devincoughlin/swift,hooman/swift,harlanhaskins/swift,karwa/swift,adrfer/swift,gottesmm/swift,roambotics/swift,parkera/swift,benlangmuir/swift,LeoShimonaka/swift,xwu/swift,zisko/swift,calebd/swift,kentya6/swift,rudkx/swift,zisko/swift,natecook1000/swift,IngmarStein/swift,ken0nek/swift,felix91gr/swift,shahmishal/swift,Jnosh/swift,sschiau/swift,xwu/swift,CodaFi/swift,jckarter/swift,djwbrown/swift,russbishop/swift,gribozavr/swift,manavgabhawala/swift,airspeedswift/swift,aschwaighofer/swift,kentya6/swift,OscarSwanros/swift,djwbrown/swift,natecook1000/swift