Added more nullability annotations, minor code tweaks

Author: Sergio0694

Microsoft.Toolkit.Mvvm/ComponentModel/ObservableRecipient.cs

@@ -118,7 +118,7 @@ protected virtual void Broadcast<T>(T oldValue, T newValue, string? propertyName
         {
             PropertyChangedMessage<T> message = new(this, propertyName, oldValue, newValue);
 
-            Messenger.Send(message);
+            _ = Messenger.Send(message);
         }
 
         /// <summary>

Microsoft.Toolkit.Mvvm/ComponentModel/ObservableValidator.cs

@@ -727,7 +727,7 @@ static Dictionary<string, string> GetDisplayNames(Type type)
 
             // This method replicates the logic of DisplayName and GetDisplayName from the
             // ValidationContext class. See the original source in the BCL for more details.
-            DisplayNamesMap.GetValue(GetType(), static t => GetDisplayNames(t)).TryGetValue(propertyName, out string? displayName);
+            _ = DisplayNamesMap.GetValue(GetType(), static t => GetDisplayNames(t)).TryGetValue(propertyName, out string? displayName);
 
             return displayName ?? propertyName;
         }

Microsoft.Toolkit.Mvvm/Input/AsyncRelayCommand.cs

@@ -146,7 +146,7 @@ public bool CanExecute(object? parameter)
         /// <inheritdoc/>
         public void Execute(object? parameter)
         {
-            ExecuteAsync(parameter);
+            _ = ExecuteAsync(parameter);
         }
 
         /// <inheritdoc/>

Microsoft.Toolkit.Mvvm/Input/AsyncRelayCommand{T}.cs

@@ -144,13 +144,13 @@ public bool CanExecute(object? parameter)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Execute(T? parameter)
         {
-            ExecuteAsync(parameter);
+            _ = ExecuteAsync(parameter);
         }
 
         /// <inheritdoc/>
         public void Execute(object? parameter)
         {
-            ExecuteAsync((T?)parameter);
+            _ = ExecuteAsync((T?)parameter);
         }
 
         /// <inheritdoc/>

Microsoft.Toolkit.Mvvm/Messaging/Internals/ConditionalWeakTable2{TKey,TValue}.cs

@@ -6,6 +6,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 
@@ -33,7 +34,7 @@ internal sealed class ConditionalWeakTable2<TKey, TValue>
         private readonly LinkedList<WeakReference<TKey>> keys = new();
 
         /// <inheritdoc cref="ConditionalWeakTable{TKey,TValue}.TryGetValue"/>
-        public bool TryGetValue(TKey key, out TValue? value)
+        public bool TryGetValue(TKey key, [NotNullWhen(true)] out TValue? value)
         {
             return this.table.TryGetValue(key, out value);
         }

Microsoft.Toolkit.Mvvm/Messaging/Messages/AsyncCollectionRequestMessage{T}.cs

@@ -99,7 +99,7 @@ public async Task<IReadOnlyCollection<T>> GetResponsesAsync(CancellationToken ca
         {
             if (cancellationToken.CanBeCanceled)
             {
-                cancellationToken.Register(this.cancellationTokenSource.Cancel);
+                _ = cancellationToken.Register(this.cancellationTokenSource.Cancel);
             }
 
             List<T> results = new(this.responses.Count);
@@ -119,7 +119,7 @@ public async IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellati
         {
             if (cancellationToken.CanBeCanceled)
             {
-                cancellationToken.Register(this.cancellationTokenSource.Cancel);
+                _ = cancellationToken.Register(this.cancellationTokenSource.Cancel);
             }
 
             foreach (var (task, func) in this.responses)

Microsoft.Toolkit.Mvvm/Messaging/StrongReferenceMessenger.cs

@@ -138,7 +138,7 @@ public void Register<TRecipient, TMessage, TToken>(TRecipient recipient, TToken
 
                 set ??= new HashSet<IMapping>();
 
-                set.Add(mapping);
+                _ = set.Add(mapping);
             }
         }
 
@@ -169,12 +169,12 @@ public void UnregisterAll(object recipient)
                         // dictionary (a hashed collection) only costs O(1) in the best case, while
                         // if we had tried to iterate the whole dictionary every time we would have
                         // paid an O(n) minimum cost for each single remove operation.
-                        this.typesMap.TryRemove(mapping.TypeArguments);
+                        _ = this.typesMap.TryRemove(mapping.TypeArguments);
                     }
                 }
 
                 // Remove the associated set in the recipients map
-                this.recipientsMap.TryRemove(key);
+                _ = this.recipientsMap.TryRemove(key);
             }
         }
 
@@ -246,7 +246,7 @@ public void UnregisterAll<TToken>(object recipient, TToken token)
                         holder.Count == 0)
                     {
                         // If the map is empty, remove the recipient entirely from its container
-                        map.TryRemove(key);
+                        _ = map.TryRemove(key);
 
                         // If no handlers are left at all for the recipient, across all
                         // message types and token types, remove the set of mappings
@@ -257,7 +257,7 @@ public void UnregisterAll<TToken>(object recipient, TToken token)
                             set.Remove(Unsafe.As<IMapping>(map)) &&
                             set.Count == 0)
                         {
-                            this.recipientsMap.TryRemove(key);
+                            _ = this.recipientsMap.TryRemove(key);
                         }
                     }
                 }
@@ -312,14 +312,14 @@ public void Unregister<TMessage, TToken>(object recipient, TToken token)
                     // of the specific token value (ie. the channel used to receive messages of that type).
                     // We can remove the map entirely from this container, and remove the link to the map itself
                     // to the current mapping between existing registered recipients (or entire recipients too).
-                    mapping.TryRemove(key);
+                    _ = mapping.TryRemove(key);
 
                     HashSet<IMapping> set = this.recipientsMap[key];
 
                     if (set.Remove(mapping) &&
                         set.Count == 0)
                     {
-                        this.recipientsMap.TryRemove(key);
+                        _ = this.recipientsMap.TryRemove(key);
                     }
                 }
             }

Microsoft.Toolkit.Mvvm/Messaging/WeakReferenceMessenger.cs

@@ -98,7 +98,7 @@ public bool IsRegistered<TMessage, TToken>(object recipient, TToken token)
                 return
                     this.recipientsMap.TryGetValue(type2, out RecipientsTable? table) &&
                     table.TryGetValue(recipient, out IDictionarySlim? mapping) &&
-                    Unsafe.As<DictionarySlim<TToken, object>>(mapping)!.ContainsKey(token);
+                    Unsafe.As<DictionarySlim<TToken, object>>(mapping).ContainsKey(token);
             }
         }
 
@@ -145,7 +145,7 @@ public void UnregisterAll(object recipient)
                 // as that is responsibility of a separate method defined below.
                 while (enumerator.MoveNext())
                 {
-                    enumerator.Value.Remove(recipient);
+                    _ = enumerator.Value.Remove(recipient);
                 }
             }
         }
@@ -166,7 +166,7 @@ public void UnregisterAll<TToken>(object recipient, TToken token)
                     if (enumerator.Key.TToken == typeof(TToken) &&
                         enumerator.Value.TryGetValue(recipient, out IDictionarySlim? mapping))
                     {
-                        Unsafe.As<DictionarySlim<TToken, object>>(mapping)!.TryRemove(token);
+                        _ = Unsafe.As<DictionarySlim<TToken, object>>(mapping).TryRemove(token);
                     }
                 }
             }
@@ -186,7 +186,7 @@ public void Unregister<TMessage, TToken>(object recipient, TToken token)
                 if (this.recipientsMap.TryGetValue(type2, out RecipientsTable? value) &&
                     value.TryGetValue(recipient, out IDictionarySlim? mapping))
                 {
-                    Unsafe.As<DictionarySlim<TToken, object>>(mapping)!.TryRemove(token);
+                    _ = Unsafe.As<DictionarySlim<TToken, object>>(mapping).TryRemove(token);
                 }
             }
         }
@@ -334,7 +334,7 @@ private void CleanupWithoutLock()
                 // Remove the handler maps for recipients that are still alive but with no handlers
                 foreach (object recipient in emptyRecipients.Span)
                 {
-                    enumerator.Value.Remove(recipient);
+                    _ = enumerator.Value.Remove(recipient);
                 }
 
                 // Track the type combinations with no recipients or handlers left
@@ -347,7 +347,7 @@ private void CleanupWithoutLock()
             // Remove all the mappings with no handlers left
             foreach (Type2 key in type2s.Span)
             {
-                this.recipientsMap.TryRemove(key);
+                _ = this.recipientsMap.TryRemove(key);
             }
         }