Mixed nullable fixes (beardgame#184)

Bearded.Utilities/Algorithms/CoffmanGraham.cs

@@ -177,7 +177,7 @@ private static ImmutableList<ImmutableHashSet<T>> createLayers<T>(
 
     public static ISolver SolverForReducedGraphs(int maxLayerSize) => new ReducedGraphSolver(maxLayerSize);
 
-    private struct DecreasingNumberSequence : IComparable<DecreasingNumberSequence>, IComparable
+    private readonly struct DecreasingNumberSequence : IComparable<DecreasingNumberSequence>, IComparable
     {
         private readonly ImmutableList<int> numbers;
 
@@ -186,7 +186,7 @@ private DecreasingNumberSequence(ImmutableList<int> numbers)
             this.numbers = numbers;
         }
 
-        public int CompareTo(object obj) => CompareTo((DecreasingNumberSequence) obj);
+        public int CompareTo(object? obj) => CompareTo((DecreasingNumberSequence) (obj ?? throw new ArgumentNullException()));
 
         public int CompareTo(DecreasingNumberSequence other)
         {

Bearded.Utilities/Collections/PrefixTrie.cs

@@ -13,7 +13,7 @@ private struct Node
     {
         private readonly Dictionary<char, Node>? values;
 
-        public string Key { get; }
+        public string? Key { get; }
 
         #region creating
 

Bearded.Utilities/Collections/PriorityQueue.cs

@@ -9,7 +9,9 @@ namespace Bearded.Utilities.Collections;
 /// </summary>
 /// <typeparam name="TPriority"></typeparam>
 /// <typeparam name="TValue"></typeparam>
-public sealed class PriorityQueue<TPriority, TValue> : StaticPriorityQueue<TPriority, TValue> where TPriority : IComparable<TPriority>
+public sealed class PriorityQueue<TPriority, TValue> : StaticPriorityQueue<TPriority, TValue>
+    where TPriority : IComparable<TPriority>
+    where TValue : notnull
 {
     private readonly Dictionary<TValue, int> valueDict = new Dictionary<TValue, int>();
 

Bearded.Utilities/Core/Environment.cs

@@ -43,7 +43,7 @@ private static Platform detectPlatform()
     #endregion
 
     #region User settings directory
-    private static string userSettingsDirectory;
+    private static string? userSettingsDirectory;
 
     private static string buildUserSettingsDirectory()
     {
@@ -67,8 +67,7 @@ private static string buildUserSettingsDirectory()
                     return linuxConfigDir;
 
                 var linuxHomeDir = System.Environment.GetEnvironmentVariable("HOME");
-                // ReSharper disable once AssignNullToNotNullAttribute
-                return string.IsNullOrEmpty(linuxConfigDir) ? "." : Path.Combine(linuxHomeDir, ".config");
+                return string.IsNullOrEmpty(linuxConfigDir) ? "." : Path.Combine(linuxHomeDir!, ".config");
             default:
                 throw new InvalidOperationException("Encountered unknown platform.");
         }
@@ -80,7 +79,7 @@ private static string buildUserSettingsDirectory()
     /// For OSX: ~/Library/Application Support
     /// For Linux: ~/.config
     /// </summary>
-    public static string UserSettingsDirectory => userSettingsDirectory ?? (userSettingsDirectory = buildUserSettingsDirectory());
+    public static string UserSettingsDirectory => userSettingsDirectory ??= buildUserSettingsDirectory();
 
     /// <summary>
     /// Gets the default user setting directory for a given game name.

Bearded.Utilities/Core/Singleton.cs

@@ -4,7 +4,7 @@ namespace Bearded.Utilities;
 
 public abstract class Singleton<TSelf> where TSelf : Singleton<TSelf>
 {
-    public static TSelf Instance { get; private set; }
+    public static TSelf? Instance { get; private set; }
 
     protected Singleton()
     {

Bearded.Utilities/Core/StaticRandom.cs

@@ -12,13 +12,13 @@ public static class StaticRandom
 {
     #region Threadsafe random
     [ThreadStatic]
-    private static Random random;
+    private static Random? random;
 
     /// <summary>
     /// The thread safe instance of Random used by StaticRandom
     /// </summary>
     // is internal for use as default random in Linq.Extensions
-    internal static Random Random => random ?? (random = new Random());
+    internal static Random Random => random ??= new Random();
 
     /// <summary>
     /// Overrides the Random object for the calling thread by one with the given seed.

Bearded.Utilities/IO/Logger.cs

@@ -234,7 +234,7 @@ private static void ensureListCapacity(List<Entry> list, int neededCapacity)
     /// <summary>
     /// If RaiseEvents is true, this event is raised every time an event is added to the log.
     /// </summary>
-    public event LogEvent Logged;
+    public event LogEvent? Logged;
 
     #region settings
 

Bearded.Utilities/Linq/Extensions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 
 namespace Bearded.Utilities.Linq;
@@ -152,8 +153,13 @@ public static int AddSorted<T>(this List<T> list, T item, IComparer<T> comparer)
     /// <param name="result">The resulting transformed value.</param>
     /// <param name="transform">The function transforming the value into the result.</param>
     /// <returns>True if the value was found, false otherwise.</returns>
-    public static bool TryGetTransformedValue<TKey, TValue, TNewValue>(this Dictionary<TKey, TValue> dictionary, TKey key, out TNewValue result,
-        Func<TValue, TNewValue> transform)
+    public static bool TryGetTransformedValue<TKey, TValue, TNewValue>(
+        this Dictionary<TKey, TValue> dictionary,
+        TKey key,
+        [MaybeNullWhen(false)] out TNewValue result,
+        Func<TValue, TNewValue> transform
+    )
+        where TKey : notnull
     {
         if (dictionary.TryGetValue(key, out var value))
         {
@@ -171,7 +177,9 @@ public static bool TryGetTransformedValue<TKey, TValue, TNewValue>(this Dictiona
     /// <param name="dictionary">The dictionary.</param>
     /// <param name="other">KeyValuePairs to add.</param>
     public static void AddRange<TKey, TValue>(this IDictionary<TKey, TValue> dictionary,
-        IEnumerable<KeyValuePair<TKey, TValue>> other)
+        IEnumerable<KeyValuePair<TKey, TValue>> other
+    )
+        where TKey : notnull
     {
         foreach (var pair in other)
         {
@@ -181,13 +189,15 @@ public static void AddRange<TKey, TValue>(this IDictionary<TKey, TValue> diction
 
     public static TValue? ValueOrNull<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key)
         where TValue : class
+        where TKey : notnull
     {
         dict.TryGetValue(key, out var value);
         return value;
     }
 
     public static TValue ValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key)
         where TValue : struct
+        where TKey : notnull
     {
         dict.TryGetValue(key, out var value);
         return value;