Now use if-null test

Author: Stephen Hawley

SwiftReflector/MarshalEngine.cs

@@ -1617,8 +1617,14 @@ CSBaseExpression MarshalNominal (CSParameter p)
 
 		CSLine ThrowOnNull (CSIdentifier parameterName)
 		{
-			use.AddIfNotPresent (typeof (SwiftRuntimeLibrary.Exceptions));
-			return CSFunctionCall.FunctionCallLine ("Exceptions.ThrowOnNull", parameterName, CSFunctionCall.Nameof (parameterName));
+			// code to generate:
+			// if (p == null)
+			//    throw new ArgumentNullException (nameof (p));
+
+			var ifTest = parameterName == CSConstant.Null;
+			var throwCall = CSThrow.ThrowLine (new ArgumentNullException (), CSFunctionCall.Nameof (parameterName));
+			var ifStatement = new CSIfElse (ifTest, CSCodeBlock.Create (throwCall), null);
+			return new CSLine (ifStatement, false);
 		}
 
 		CSBaseExpression MarshalClass (CSParameter p, NamedTypeSpec cl)

SwiftRuntimeLibrary.iOS/SwiftRuntimeLibrary.iOS.csproj

@@ -135,8 +135,8 @@
     <Compile Include="..\SwiftRuntimeLibrary\SwiftMarshal\DynamicLib.cs">
       <Link>SwiftMarshal\DynamicLib.cs</Link>
     </Compile>
-    <Compile Include="..\SwiftRuntimeLibrary\SwiftMarshal\Exceptions.cs">
-      <Link>SwiftMarshal\Exceptions.cs</Link>
+    <Compile Include="..\SwiftRuntimeLibrary\SwiftMarshal\Extensions.cs">
+      <Link>SwiftMarshal\Extentions.cs</Link>
     </Compile>
     <Compile Include="..\SwiftRuntimeLibrary\SwiftMarshal\Memory.cs">
       <Link>SwiftMarshal\Memory.cs</Link>

SwiftRuntimeLibrary/Exceptions.cs

@@ -3,7 +3,7 @@
 
 using System;
 namespace SwiftRuntimeLibrary {
-	public static class Exceptions {
+	internal static class Exceptions {
 		public static T ThrowOnNull<T> (T o, string name, string message = null) where T : class
 		{
 			name = name ?? "::no name supplied::";