Reuse .NET NativeOverlapped struct instead of generating our own

Closes #545

Author: AArnott

src/Microsoft.Windows.CsWin32/Generator.cs

@@ -41,13 +41,20 @@ public class Generator : IDisposable
 
     internal static readonly SyntaxAnnotation IsRetValAnnotation = new SyntaxAnnotation("RetVal");
 
+    /// <summary>
+    /// A map of .NET interop structs to use, keyed by the native structs that should <em>not</em> be generated.
+    /// </summary>
+    /// <devremarks>
+    /// When adding to this dictionary, consider also adding to <see cref="BannedAPIsWithoutMarshaling"/>.
+    /// </devremarks>
     internal static readonly Dictionary<string, TypeSyntax> BclInteropStructs = new Dictionary<string, TypeSyntax>(StringComparer.Ordinal)
     {
         { nameof(System.Runtime.InteropServices.ComTypes.FILETIME), ParseTypeName("global::System.Runtime.InteropServices.ComTypes.FILETIME") },
         { nameof(Guid), ParseTypeName("global::System.Guid") },
         { "OLD_LARGE_INTEGER", PredefinedType(Token(SyntaxKind.LongKeyword)) },
         { "LARGE_INTEGER", PredefinedType(Token(SyntaxKind.LongKeyword)) },
         { "ULARGE_INTEGER", PredefinedType(Token(SyntaxKind.ULongKeyword)) },
+        { "OVERLAPPED", ParseTypeName("global::System.Threading.NativeOverlapped") },
     };
 
     internal static readonly Dictionary<string, TypeSyntax> AdditionalBclInteropStructsMarshaled = new Dictionary<string, TypeSyntax>(StringComparer.Ordinal)
@@ -372,7 +379,8 @@ private enum FriendlyOverloadOf
         .Add("GetLastError", "Do not generate GetLastError. Call Marshal.GetLastWin32Error() instead. Learn more from https://docs.microsoft.com/dotnet/api/system.runtime.interopservices.marshal.getlastwin32error")
         .Add("OLD_LARGE_INTEGER", "Use the C# long keyword instead.")
         .Add("LARGE_INTEGER", "Use the C# long keyword instead.")
-        .Add("ULARGE_INTEGER", "Use the C# ulong keyword instead.");
+        .Add("ULARGE_INTEGER", "Use the C# ulong keyword instead.")
+        .Add("OVERLAPPED", "Use System.Threading.NativeOverlapped instead.");
 
     internal static ImmutableDictionary<string, string> BannedAPIsWithMarshaling { get; } = BannedAPIsWithoutMarshaling
         .Add("VARIANT", "Use `object` instead of VARIANT when in COM interface mode. VARIANT can only be emitted when emitting COM interfaces as structs.");

test/GenerationSandbox.Tests/GeneratedForm.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Runtime.InteropServices;
+using System.Threading;
 using Microsoft.Win32.SafeHandles;
 using Windows.Win32;
 using Windows.Win32.Foundation;
@@ -53,4 +54,10 @@ private static void PreserveSigBasedOnMetadata()
         IDirectorySearch ds = null!;
         HRESULT hr = ds.GetNextRow(0);
     }
+
+    private static unsafe void OverlappedAPIs()
+    {
+        NativeOverlapped overlapped = default;
+        PInvoke.WriteFile(default(HANDLE), null, 0, null, &overlapped);
+    }
 }

test/GenerationSandbox.Tests/NativeMethods.txt

@@ -21,3 +21,4 @@ ShellLink
 WER_REPORT_INFORMATION
 wglGetProcAddress
 WPARAM
+WriteFile