Fix for breaking ref.null

Author: iainsmith

Sources/WAT/Parser/WastParser.swift

@@ -63,9 +63,9 @@ struct WastParser {
         mutating func visitRefFunc(functionIndex: UInt32) throws {
             addValue(.ref(.function(FunctionAddress(functionIndex))))
         }
-        mutating func visitRefNull(type: HeapType) throws {
+        mutating func visitRefNull(type: ReferenceType) throws {
             let value: Reference
-            switch type {
+            switch type.heapType {
             case .externRef: value = .extern(nil)
             case .funcRef: value = .function(nil)
             }

Sources/WasmKit/Execution/Instructions/InstructionSupport.swift

@@ -105,11 +105,11 @@ extension Int32: InstructionImmediate {
 
 extension Instruction.RefNullOperand {
     init(result: VReg, type: ReferenceType) {
-        self.init(result: result, rawType: 0) // need to figure out rawType here
+        self.init(result: result, rawType: type.heapType.rawValue) // need to figure out rawType here
     }
 
     var type: ReferenceType {
-        ReferenceType(isNullable: true, heapType: .funcRef) // is this still a valid conversion?
+        ReferenceType(isNullable: true, heapType: HeapType(rawValue: rawType)!) // is this still a valid conversion?
     }
 }
 

Sources/WasmTypes/WasmTypes.swift

@@ -14,7 +14,7 @@ public struct FunctionType: Equatable, Hashable {
     public let results: [ValueType]
 }
 
-public enum HeapType: Equatable, Hashable {
+public enum HeapType: UInt8, Equatable, Hashable {
     /// A reference to any kind of function.
     case funcRef // -> to be renamed func