Fix IntPtr <-> UIntPtr casts by introducing calls to ToPointer()

ICSharpCode.Decompiler/CSharp/Transforms/IntroduceUnsafeModifier.cs

@@ -18,6 +18,7 @@
 
 using System;
 using ICSharpCode.NRefactory.CSharp;
+using ICSharpCode.NRefactory.TypeSystem;
 
 namespace ICSharpCode.Decompiler.CSharp.Transforms
 {
@@ -106,5 +107,14 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			base.VisitStackAllocExpression(stackAllocExpression);
 			return true;
 		}
+		
+		public override bool VisitInvocationExpression(InvocationExpression invocationExpression)
+		{
+			bool result = base.VisitInvocationExpression(invocationExpression);
+			var rr = invocationExpression.GetResolveResult();
+			if (rr != null && rr.Type is PointerType)
+				return true;
+			return result;
+		}
 	}
 }

ICSharpCode.Decompiler/CSharp/TranslatedExpression.cs

@@ -160,6 +160,13 @@ namespace ICSharpCode.Decompiler.CSharp
 				return ConvertToBoolean(expressionBuilder);
 			if (type.Equals(targetType))
 				return this;
+			if ((type.IsKnownType(KnownTypeCode.IntPtr) && targetType.IsKnownType(KnownTypeCode.UIntPtr))
+			    || (type.IsKnownType(KnownTypeCode.UIntPtr) && targetType.IsKnownType(KnownTypeCode.IntPtr))) {
+				return Expression.Invoke("ToPointer")
+					.WithoutILInstruction()
+					.WithRR(new ResolveResult(new PointerType(expressionBuilder.compilation.FindType(KnownTypeCode.Void))))
+					.ConvertTo(targetType, expressionBuilder);
+			}
 			if (type.Kind == TypeKind.ByReference && targetType.Kind == TypeKind.Pointer && Expression is DirectionExpression) {
 				// convert from reference to pointer
 				Expression arg = ((DirectionExpression)Expression).Expression.Detach();