fix nullability warnings

Author: lofcz

src/FastCloner/Code/AhoCorasick.cs

@@ -26,7 +26,7 @@ private void BuildTrie()
             Node current = root;
             foreach (char c in pattern)
             {
-                if (!current.Children.TryGetValue(c, out Node value))
+                if (!current.Children.TryGetValue(c, out Node? value))
                 {
                     value = new Node();
                     current.Children[c] = value;

src/FastCloner/Code/Extensions.cs

@@ -15,7 +15,7 @@ public static bool Contains(this string source, string value, StringComparison c
         return source.IndexOf(value, comparisonType) >= 0;
     }
 
-    public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey key, TValue defaultValue = default(TValue))
+    public static TValue? GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey key, TValue? defaultValue = default)
     {
         return dictionary.TryGetValue(key, out TValue value) ? value : defaultValue;
     }

src/FastCloner/Code/FastCloneState.cs

@@ -332,6 +332,8 @@ public MiniDictionary() : this(DefaultCapacity) { }
 
         public MiniDictionary(int capacity)
         {
+            buckets = null!;
+            entries = null!;
             int size = RoundUpToPowerOf2(capacity < DefaultCapacity ? DefaultCapacity : capacity);
             Initialize(size);
         }

src/FastCloner/Code/FastClonerCache.cs

@@ -227,7 +227,11 @@ private sealed class CacheStore
     public static object? GetOrAddStructAsObject(Type type, Func<Type, object?> valueFactory) => cacheStore.StructCache.GetOrAdd(type, valueFactory);
     public static object GetOrAddDeepClassTo(Type type, Func<Type, object> valueFactory) => cacheStore.DeepClassToCache.GetOrAdd(type, valueFactory);
     public static object GetOrAddShallowClassTo(Type type, Func<Type, object> valueFactory) => cacheStore.ShallowClassToCache.GetOrAdd(type, valueFactory);
-    public static T GetOrAddConvertor<T>(Type from, Type to, Func<Type, Type, T> valueFactory) => (T)cacheStore.TypeConvertCache.GetOrAdd(from, to, (f, t) => valueFactory(f, t));
+    public static T GetOrAddConvertor<T>(Type from, Type to, Func<Type, Type, T> valueFactory)
+    {
+        object? value = cacheStore.TypeConvertCache.GetOrAdd(from, to, (f, t) => valueFactory(f, t)!);
+        return (T)value!;
+    }
     public static CloneBehavior? GetOrAddMemberBehavior(MemberInfo memberInfo, Func<MemberInfo, CloneBehavior?> valueFactory) => cacheStore.MemberBehaviorCache.GetOrAdd(memberInfo, valueFactory);
     public static CloneBehavior? GetOrAddAttributedTypeBehavior(Type type, Func<Type, CloneBehavior?> valueFactory)
         => cacheStore.AttributedTypeBehaviorCache.GetOrAdd(type, valueFactory);

src/FastCloner/Code/FastClonerExprGenerator.cs

@@ -1421,7 +1421,7 @@ private static object GenerateImmutableDictionaryProcessor(Type dictType, Type k
             enumerator,
             Expression.Call(
                 Expression.Convert(typedFrom, enumerableType),
-                getEnumeratorMethod
+                getEnumeratorMethod!
             )
         );
 
@@ -1457,7 +1457,7 @@ private static object GenerateImmutableDictionaryProcessor(Type dictType, Type k
 
         BlockExpression loopBody = Expression.Block(
             [kvp, key, value],
-            Expression.Assign(kvp, Expression.Property(enumerator, current)),
+            Expression.Assign(kvp, Expression.Property(enumerator, current!)),
             Expression.Assign(
                 key,
                 keyForAdd
@@ -2081,7 +2081,7 @@ private static object GenerateImmutableSetProcessor(Type setType, Type elementTy
             enumerator,
             Expression.Call(
                 Expression.Convert(typedFrom, enumerableType),
-                getEnumeratorMethod
+                getEnumeratorMethod!
             )
         );
 

src/FastCloner/Code/FastClonerGenerator.cs

@@ -683,7 +683,7 @@ private static bool TryGetGenericInterfaceArgument(Type type, Type genericInterf
             // value types: avoid the worklist because ClonerToExprGenerator.GenerateClonerInternal doesn't support value types
             if (objType.IsValueType())
             {
-                object cloned = recursiveCloner(obj, state);
+                object cloned = recursiveCloner!(obj, state);
                 state.AddKnownRef(obj, cloned);
                 return cloned;
             }
@@ -706,15 +706,15 @@ private static bool TryGetGenericInterfaceArgument(Type type, Type genericInterf
                 // value types: avoid the worklist because ClonerToExprGenerator.GenerateClonerInternal doesn't support value types
                 if (objType.IsValueType())
                 {
-                    object cloned = recursiveCloner(obj, state);
+                    object cloned = recursiveCloner!(obj, state);
                     state.AddKnownRef(obj, cloned);
                     return cloned;
                 }
 
                 return CloneClassShallowAndTrack(obj, state);
             }
 
-            return recursiveCloner(obj, state);
+            return recursiveCloner!(obj, state);
         }
         finally
         {
@@ -1152,8 +1152,8 @@ internal static T[] Clone1DimArraySafeInternal<T>(T[] obj, FastCloneState state)
 #if NET6_0_OR_GREATER
         foreach (KeyValuePair<TKey, TValue> kvp in obj)
         {
-            ref TValue valueRef = ref CollectionsMarshal.GetValueRefOrAddDefault(result, kvp.Key, out _);
-            valueRef = ignoreValues ? default! : kvp.Value;
+            ref TValue? valueRef = ref CollectionsMarshal.GetValueRefOrAddDefault(result, kvp.Key, out _);
+            valueRef = ignoreValues ? default : kvp.Value;
         }
 #else
         foreach (KeyValuePair<TKey, TValue> kvp in obj)

src/FastCloner/Code/FieldAccessorGenerator.cs

@@ -7,15 +7,15 @@ internal static class FieldAccessorGenerator
 {
     internal static Action<object, object> GetFieldSetter(FieldInfo field)
     {
-        return (Action<object, object>)FastClonerCache.GetOrAddField(field.DeclaringType, field.Name, _ => CreateFieldSetter(field));
+        return (Action<object, object>)FastClonerCache.GetOrAddField(field.DeclaringType!, field.Name, _ => CreateFieldSetter(field))!;
     }
 
     private static Action<object, object> CreateFieldSetter(FieldInfo field)
     {
         ParameterExpression targetParam = Expression.Parameter(typeof(object), "target");
         ParameterExpression valueParam = Expression.Parameter(typeof(object), "value");
 
-        UnaryExpression targetCast = Expression.Convert(targetParam, field.DeclaringType);
+        UnaryExpression targetCast = Expression.Convert(targetParam, field.DeclaringType!);
 
         Expression body;