More nullability

src/BizHawk.Common/Extensions/CollectionExtensions.cs

@@ -1,6 +1,4 @@
-#nullable disable
-
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -16,7 +14,8 @@ namespace BizHawk.Common.CollectionExtensions
 			return desc ? source.OrderByDescending(keySelector) : source.OrderBy(keySelector);
 		}
 
-		public static int LowerBoundBinarySearch<T, TKey>(this IList<T> list, Func<T, TKey> keySelector, TKey key) where TKey : IComparable<TKey>
+		public static int LowerBoundBinarySearch<T, TKey>(this IList<T> list, Func<T, TKey> keySelector, TKey key)
+			where TKey : IComparable<TKey>
 		{
 			int min = 0;
 			int max = list.Count;
@@ -73,7 +72,7 @@ namespace BizHawk.Common.CollectionExtensions
 		/// <exception cref="InvalidOperationException"><paramref name="key"/> not found after mapping <paramref name="keySelector"/> over <paramref name="list"/></exception>
 		/// <remarks>implementation from https://stackoverflow.com/a/1766369/7467292</remarks>
 		public static T BinarySearch<T, TKey>(this IList<T> list, Func<T, TKey> keySelector, TKey key)
-		where TKey : IComparable<TKey>
+			where TKey : IComparable<TKey>
 		{
 			int min = 0;
 			int max = list.Count;

src/BizHawk.Common/Extensions/IOExtensions.cs

@@ -1,7 +1,4 @@
-#nullable disable
-
-using System;
-using System.IO;
+using System.IO;
 using System.Text;
 
 namespace BizHawk.Common.IOExtensions

src/BizHawk.Common/OSTailoredCode.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
@@ -21,7 +19,7 @@ namespace BizHawk.Common
 
 		private static readonly Lazy<ILinkedLibManager> _LinkedLibManager = new Lazy<ILinkedLibManager>(() => CurrentOS switch
 		{
-			DistinctOS.Linux => (ILinkedLibManager) new UnixMonoLLManager(),
+			DistinctOS.Linux => new UnixMonoLLManager(),
 			DistinctOS.macOS => new UnixMonoLLManager(),
 			DistinctOS.Windows => new WindowsLLManager(),
 			_ => throw new ArgumentOutOfRangeException()
@@ -130,8 +128,8 @@ namespace BizHawk.Common
 		/// <param name="checkStdout">stdout is discarded if false</param>
 		/// <param name="checkStderr">stderr is discarded if false</param>
 		/// <remarks>OS is implicit and needs to be checked at callsite. Returned <see cref="Process"/> has not been started.</remarks>
-		public static Process ConstructSubshell(string cmd, string args, bool checkStdout = true, bool checkStderr = false) =>
-			new Process {
+		public static Process ConstructSubshell(string cmd, string args, bool checkStdout = true, bool checkStderr = false)
+			=> new Process {
 				StartInfo = new ProcessStartInfo {
 					Arguments = args,
 					CreateNoWindow = true,

src/BizHawk.Common/SettingsUtil.cs

@@ -1,6 +1,4 @@
-#nullable disable
-
-using System;
+using System;
 using System.Collections.Generic;
 using System.Reflection;
 using System.Reflection.Emit;
@@ -13,18 +11,26 @@ namespace BizHawk.Common
 	{
 		private sealed class DefaultValueSetter
 		{
-			public Action<object, object[]> SetDefaultValues;
-			public object[] DefaultValues;
+			public readonly Action<object, object[]> SetDefaultValues;
+
+			public readonly object[] DefaultValues;
+
+			public DefaultValueSetter(Action<object, object[]> setDefaultValues, object[] defaultValues)
+			{
+				SetDefaultValues = setDefaultValues;
+				DefaultValues = defaultValues;
+			}
 		}
 
 
-		private static IDictionary<Type, DefaultValueSetter> DefaultValueSetters = new ConcurrentDictionary<Type, DefaultValueSetter>();
+		private static readonly IDictionary<Type, DefaultValueSetter> DefaultValueSetters = new ConcurrentDictionary<Type, DefaultValueSetter>();
 
 		/// <summary>
 		/// set all properties (not fields!) of obj with a DefaultValueAttribute to that value
 		/// </summary>
 		/// <param name="obj">the obj to act on</param>
 		public static void SetDefaultValues<T>(T obj)
+			where T : notnull
 		{
 			if (!DefaultValueSetters.TryGetValue(typeof(T), out var f))
 			{
@@ -34,7 +40,7 @@ namespace BizHawk.Common
 			f.SetDefaultValues(obj, f.DefaultValues);
 		}
 
-		private static Dictionary<Type, OpCode> IntTypes = new Dictionary<Type,OpCode>
+		private static readonly Dictionary<Type, OpCode> IntTypes = new Dictionary<Type,OpCode>
 		{
 			{ typeof(byte), OpCodes.Conv_U1 },
 			{ typeof(sbyte), OpCodes.Conv_I1 },
@@ -64,9 +70,9 @@ namespace BizHawk.Common
 				MethodInfo method = prop.GetSetMethod(true);
 				foreach (object attr in prop.GetCustomAttributes(true))
 				{
-					if (attr is DefaultValueAttribute)
+					if (attr is DefaultValueAttribute dvAttr)
 					{
-						object value = (attr as DefaultValueAttribute).Value;
+						var value = dvAttr.Value;
 						Type desiredType = method.GetParameters()[0].ParameterType;
 						Type sourceType = value.GetType();
 
@@ -98,11 +104,10 @@ namespace BizHawk.Common
 			}
 			il.Emit(OpCodes.Pop);
 			il.Emit(OpCodes.Ret);
-			return new DefaultValueSetter
-			{
-				SetDefaultValues = (Action<object, object[]>)dyn.CreateDelegate(typeof(Action<object, object[]>)),
-				DefaultValues = DefaultValues.ToArray()
-			};
+			return new DefaultValueSetter(
+				(Action<object, object[]>) dyn.CreateDelegate(typeof(Action<object, object[]>)),
+				DefaultValues.ToArray()
+			);
 		}
 	}
 }

src/BizHawk.Common/UndoHistory.cs

@@ -1,6 +1,4 @@
-#nullable disable
-
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace BizHawk.Common

src/BizHawk.Common/Win32/MotWHack.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 namespace BizHawk.Common
 {
 	/// <remarks>This code (and an import for <see cref="Win32Imports.DeleteFileW"/>) is duplicated in each executable project because it needs to be used before loading assemblies.</remarks>

src/BizHawk.Common/Win32/ProcessorFeatureImports.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System.Runtime.InteropServices;
 
 namespace BizHawk.Common

src/BizHawk.Version/VersionInfo.cs

@@ -1,4 +1,4 @@
-#nullable disable
+#nullable enable
 
 using System.IO;
 using System.Reflection;
@@ -14,7 +14,7 @@ internal static class VersionInfo
 	public const string HomePage = "http://tasvideos.org/BizHawk.html";
 	public static readonly bool DeveloperBuild = true;
 
-	public static readonly string CustomBuildString;
+	public static readonly string? CustomBuildString;
 
 	public static string GetEmuVersion()
 	{