Rely on ASTVisitor::visit for Decl visiting in the AST walker and provide some guidance for implementers in the file comment.
Rely on ASTVisitor::visit for Decl visiting in the
AST walker and provide some guidance for implementers
in the file comment.

Swift SVN r28790

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