[AST] Adopt Type::transformRec() in Type::subst().
[AST] Adopt Type::transformRec() in Type::subst().

Type substitution is a special transform with semantics that require
the explicit recursion control provided by transformRec(), i.e., a
transform might correctly produce the *same* type but must not
recurse.

huonw/swift,calebd/swift,lorentey/swift,stephentyrone/swift,zisko/swift,Jnosh/swift,practicalswift/swift,glessard/swift,return/swift,hughbe/swift,jtbandes/swift,ahoppen/swift,jckarter/swift,djwbrown/swift,manavgabhawala/swift,allevato/swift,milseman/swift,tinysun212/swift-windows,jopamer/swift,atrick/swift,hughbe/swift,jmgc/swift,parkera/swift,karwa/swift,stephentyrone/swift,gottesmm/swift,JGiola/swift,tkremenek/swift,parkera/swift,swiftix/swift,glessard/swift,tjw/swift,aschwaighofer/swift,sschiau/swift,aschwaighofer/swift,atrick/swift,natecook1000/swift,arvedviehweger/swift,gregomni/swift,rudkx/swift,manavgabhawala/swift,milseman/swift,parkera/swift,JaSpa/swift,tjw/swift,zisko/swift,shahmishal/swift,zisko/swift,ahoppen/swift,practicalswift/swift,swiftix/swift,jtbandes/swift,practicalswift/swift,brentdax/swift,CodaFi/swift,nathawes/swift,hooman/swift,xwu/swift,djwbrown/swift,danielmartin/swift,gregomni/swift,xedin/swift,CodaFi/swift,frootloops/swift,shajrawi/swift,danielmartin/swift,shajrawi/swift,xwu/swift,shahmishal/swift,milseman/swift,gmilos/swift,hughbe/swift,xwu/swift,benlangmuir/swift,gribozavr/swift,xedin/swift,uasys/swift,parkera/swift,calebd/swift,tkremenek/swift,milseman/swift,stephentyrone/swift,atrick/swift,gottesmm/swift,airspeedswift/swift,nathawes/swift,huonw/swift,nathawes/swift,zisko/swift,harlanhaskins/swift,uasys/swift,tardieu/swift,tkremenek/swift,lorentey/swift,practicalswift/swift,tkremenek/swift,austinzheng/swift,alblue/swift,calebd/swift,harlanhaskins/swift,alblue/swift,deyton/swift,brentdax/swift,jopamer/swift,huonw/swift,karwa/swift,calebd/swift,felix91gr/swift,airspeedswift/swift,danielmartin/swift,benlangmuir/swift,Jnosh/swift,devincoughlin/swift,uasys/swift,jmgc/swift,Jnosh/swift,JaSpa/swift,amraboelela/swift,airspeedswift/swift,jmgc/swift,felix91gr/swift,arvedviehweger/swift,allevato/swift,hooman/swift,rudkx/swift,tardieu/swift,OscarSwanros/swift,CodaFi/swift,swiftix/swift,jmgc/swift,felix91gr/swift,harlanhaskins/swift,aschwaighofer/swift,JGiola/swift,arvedviehweger/swift,alblue/swift,stephentyrone/swift,codestergit/swift,gmilos/swift,ahoppen/swift,sschiau/swift,deyton/swift,brentdax/swift,shahmishal/swift,sschiau/swift,glessard/swift,danielmartin/swift,JaSpa/swift,alblue/swift,natecook1000/swift,glessard/swift,xedin/swift,amraboelela/swift,alblue/swift,JaSpa/swift,austinzheng/swift,djwbrown/swift,tkremenek/swift,roambotics/swift,OscarSwanros/swift,karwa/swift,brentdax/swift,alblue/swift,shahmishal/swift,nathawes/swift,return/swift,gottesmm/swift,return/swift,calebd/swift,roambotics/swift,parkera/swift,practicalswift/swift,natecook1000/swift,Jnosh/swift,swiftix/swift,karwa/swift,zisko/swift,jopamer/swift,bitjammer/swift,jtbandes/swift,deyton/swift,frootloops/swift,tjw/swift,jtbandes/swift,gribozavr/swift,bitjammer/swift,xedin/swift,frootloops/swift,allevato/swift,amraboelela/swift,natecook1000/swift,gregomni/swift,return/swift,gribozavr/swift,gribozavr/swift,brentdax/swift,tjw/swift,djwbrown/swift,glessard/swift,JaSpa/swift,tjw/swift,tardieu/swift,huonw/swift,CodaFi/swift,tardieu/swift,huonw/swift,return/swift,tardieu/swift,apple/swift,jckarter/swift,shajrawi/swift,xedin/swift,austinzheng/swift,roambotics/swift,aschwaighofer/swift,return/swift,devincoughlin/swift,manavgabhawala/swift,codestergit/swift,codestergit/swift,amraboelela/swift,arvedviehweger/swift,amraboelela/swift,OscarSwanros/swift,calebd/swift,gmilos/swift,hooman/swift,shajrawi/swift,rudkx/swift,hooman/swift,natecook1000/swift,jmgc/swift,aschwaighofer/swift,atrick/swift,CodaFi/swift,milseman/swift,JaSpa/swift,felix91gr/swift,xedin/swift,OscarSwanros/swift,jmgc/swift,felix91gr/swift,shahmishal/swift,brentdax/swift,jopamer/swift,brentdax/swift,nathawes/swift,gmilos/swift,deyton/swift,arvedviehweger/swift,allevato/swift,manavgabhawala/swift,apple/swift,gregomni/swift,devincoughlin/swift,JGiola/swift,arvedviehweger/swift,uasys/swift,uasys/swift,shahmishal/swift,djwbrown/swift,zisko/swift,devincoughlin/swift,OscarSwanros/swift,jtbandes/swift,xwu/swift,tinysun212/swift-windows,karwa/swift,zisko/swift,gmilos/swift,apple/swift,danielmartin/swift,benlangmuir/swift,lorentey/swift,amraboelela/swift,xedin/swift,apple/swift,shajrawi/swift,gregomni/swift,milseman/swift,gmilos/swift,xwu/swift,hooman/swift,codestergit/swift,xwu/swift,CodaFi/swift,austinzheng/swift,parkera/swift,parkera/swift,practicalswift/swift,codestergit/swift,huonw/swift,tinysun212/swift-windows,gottesmm/swift,bitjammer/swift,jopamer/swift,benlangmuir/swift,jtbandes/swift,arvedviehweger/swift,harlanhaskins/swift,lorentey/swift,gribozavr/swift,devincoughlin/swift,lorentey/swift,Jnosh/swift,jopamer/swift,glessard/swift,danielmartin/swift,hughbe/swift,jckarter/swift,benlangmuir/swift,aschwaighofer/swift,JGiola/swift,sschiau/swift,nathawes/swift,devincoughlin/swift,practicalswift/swift,lorentey/swift,tardieu/swift,uasys/swift,tinysun212/swift-windows,airspeedswift/swift,tkremenek/swift,frootloops/swift,sschiau/swift,nathawes/swift,swiftix/swift,hughbe/swift,hooman/swift,karwa/swift,frootloops/swift,jckarter/swift,gmilos/swift,natecook1000/swift,jmgc/swift,frootloops/swift,sschiau/swift,parkera/swift,djwbrown/swift,lorentey/swift,gottesmm/swift,jopamer/swift,manavgabhawala/swift,djwbrown/swift,rudkx/swift,aschwaighofer/swift,JGiola/swift,ahoppen/swift,harlanhaskins/swift,shajrawi/swift,hughbe/swift,gottesmm/swift,stephentyrone/swift,deyton/swift,karwa/swift,karwa/swift,apple/swift,practicalswift/swift,ahoppen/swift,natecook1000/swift,stephentyrone/swift,tkremenek/swift,jckarter/swift,frootloops/swift,airspeedswift/swift,austinzheng/swift,tjw/swift,shajrawi/swift,tinysun212/swift-windows,shahmishal/swift,swiftix/swift,Jnosh/swift,jckarter/swift,gribozavr/swift,ahoppen/swift,swiftix/swift,amraboelela/swift,roambotics/swift,felix91gr/swift,gribozavr/swift,manavgabhawala/swift,apple/swift,OscarSwanros/swift,deyton/swift,CodaFi/swift,allevato/swift,JaSpa/swift,huonw/swift,danielmartin/swift,rudkx/swift,sschiau/swift,rudkx/swift,bitjammer/swift,bitjammer/swift,xwu/swift,tinysun212/swift-windows,atrick/swift,roambotics/swift,atrick/swift,harlanhaskins/swift,tardieu/swift,gregomni/swift,roambotics/swift,codestergit/swift,devincoughlin/swift,manavgabhawala/swift,austinzheng/swift,devincoughlin/swift,allevato/swift,bitjammer/swift,bitjammer/swift,return/swift,milseman/swift,austinzheng/swift,tjw/swift,jtbandes/swift,xedin/swift,allevato/swift,tinysun212/swift-windows,airspeedswift/swift,calebd/swift,alblue/swift,airspeedswift/swift,gribozavr/swift,jckarter/swift,gottesmm/swift,stephentyrone/swift,JGiola/swift,uasys/swift,shahmishal/swift,deyton/swift,Jnosh/swift,hooman/swift,shajrawi/swift,benlangmuir/swift,sschiau/swift,lorentey/swift,codestergit/swift,harlanhaskins/swift,OscarSwanros/swift,felix91gr/swift,hughbe/swift