Fix a bad forward declaration.
Fix a bad forward declaration.

CastConsumptionKind today has a uint8_t as an underlying type. I just think we
got lucky and this patch stream exposed the problem.

apple/swift,tkremenek/swift,ahoppen/swift,hooman/swift,roambotics/swift,atrick/swift,parkera/swift,ahoppen/swift,tkremenek/swift,atrick/swift,tkremenek/swift,roambotics/swift,benlangmuir/swift,hooman/swift,JGiola/swift,rudkx/swift,xwu/swift,JGiola/swift,xwu/swift,parkera/swift,ahoppen/swift,tkremenek/swift,ahoppen/swift,parkera/swift,parkera/swift,tkremenek/swift,xwu/swift,xwu/swift,benlangmuir/swift,JGiola/swift,apple/swift,apple/swift,atrick/swift,glessard/swift,rudkx/swift,tkremenek/swift,xwu/swift,parkera/swift,JGiola/swift,ahoppen/swift,JGiola/swift,gregomni/swift,xwu/swift,roambotics/swift,rudkx/swift,atrick/swift,parkera/swift,hooman/swift,atrick/swift,hooman/swift,benlangmuir/swift,rudkx/swift,rudkx/swift,parkera/swift,glessard/swift,gregomni/swift,glessard/swift,apple/swift,roambotics/swift,atrick/swift,roambotics/swift,tkremenek/swift,gregomni/swift,hooman/swift,glessard/swift,benlangmuir/swift,JGiola/swift,apple/swift,rudkx/swift,gregomni/swift,xwu/swift,gregomni/swift,ahoppen/swift,apple/swift,roambotics/swift,parkera/swift,glessard/swift,hooman/swift,gregomni/swift,glessard/swift,benlangmuir/swift,hooman/swift,benlangmuir/swift