Fix CA2216

.editorconfig

@@ -825,6 +825,9 @@ dotnet_diagnostic.CA2208.severity = warning
 # Dispose methods should call base class dispose.
 dotnet_diagnostic.CA2215.severity = warning
 
+# Disposable types should declare finalizer.
+dotnet_diagnostic.CA2216.severity = warning
+
 # Override GetHashCode on overriding Equals.
 dotnet_diagnostic.CA2218.severity = warning
 

OpenRA.Platforms.Default/Sdl2GraphicsContext.cs

@@ -19,9 +19,10 @@ namespace OpenRA.Platforms.Default
 	sealed class Sdl2GraphicsContext : ThreadAffine, IGraphicsContext
 	{
 		readonly Sdl2PlatformWindow window;
-		bool disposed;
 		IntPtr context;
 
+		public string GLVersion => OpenGL.Version;
+
 		public Sdl2GraphicsContext(Sdl2PlatformWindow window)
 		{
 			this.window = window;
@@ -269,10 +270,12 @@ namespace OpenRA.Platforms.Default
 
 		public void Dispose()
 		{
-			if (disposed)
-				return;
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
 
-			disposed = true;
+		void Dispose(bool _)
+		{
 			if (context != IntPtr.Zero)
 			{
 				SDL.SDL_GL_DeleteContext(context);
@@ -280,6 +283,9 @@ namespace OpenRA.Platforms.Default
 			}
 		}
 
-		public string GLVersion => OpenGL.Version;
+		~Sdl2GraphicsContext()
+		{
+			Dispose(false);
+		}
 	}
 }

OpenRA.Platforms.Default/Sdl2HardwareCursor.cs

@@ -45,6 +45,12 @@ namespace OpenRA.Platforms.Default
 		}
 
 		public void Dispose()
+		{
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
+
+		void Dispose(bool _)
 		{
 			if (Cursor != IntPtr.Zero)
 			{
@@ -58,5 +64,10 @@ namespace OpenRA.Platforms.Default
 				surface = IntPtr.Zero;
 			}
 		}
+
+		~Sdl2HardwareCursor()
+		{
+			Dispose(false);
+		}
 	}
 }