Fix a few nullability warnings when compiling against modern .NET

Author: mstefarov

fNbt/NullableSupport.cs

@@ -9,6 +9,7 @@ internal sealed class NullableSupport {
     }
 }
 
+#if !NETCOREAPP
 // Copied from https://github.com/dotnet/runtime/blob/main/src/libraries/System.Private.CoreLib/src/System/Diagnostics/CodeAnalysis/NullableAttributes.cs
 // and changed from public to internal.
 namespace System.Diagnostics.CodeAnalysis
@@ -28,3 +29,4 @@ internal sealed class DoesNotReturnIfAttribute : Attribute
         public bool ParameterValue { get; }
     }
 }
+#endif

fNbt/Tags/NbtCompound.cs

@@ -95,7 +95,7 @@ public override NbtTag? this[string tagName] {
         /// <exception cref="InvalidCastException"> If tag could not be cast to the desired tag. </exception>
         public T? Get<T>(string tagName) where T : NbtTag {
             if (tagName == null) throw new ArgumentNullException(nameof(tagName));
-            NbtTag result;
+            NbtTag? result;
             if (tags.TryGetValue(tagName, out result)) {
                 return (T)result;
             }
@@ -110,7 +110,7 @@ public override NbtTag? this[string tagName] {
         /// <exception cref="InvalidCastException"> If tag could not be cast to the desired tag. </exception>
         public NbtTag? Get(string tagName) {
             if (tagName == null) throw new ArgumentNullException(nameof(tagName));
-            NbtTag result;
+            NbtTag? result;
             if (tags.TryGetValue(tagName, out result)) {
                 return result;
             }
@@ -128,7 +128,7 @@ public override NbtTag? this[string tagName] {
         /// <exception cref="InvalidCastException"> If tag could not be cast to the desired tag. </exception>
         public bool TryGet<T>(string tagName, out T? result) where T : NbtTag {
             if (tagName == null) throw new ArgumentNullException(nameof(tagName));
-            NbtTag tempResult;
+            NbtTag? tempResult;
             if (tags.TryGetValue(tagName, out tempResult)) {
                 result = (T)tempResult;
                 return true;
@@ -147,7 +147,7 @@ public bool TryGet<T>(string tagName, out T? result) where T : NbtTag {
         /// <exception cref="ArgumentNullException"> <paramref name="tagName"/> is <c>null</c>. </exception>
         public bool TryGet(string tagName, out NbtTag? result) {
             if (tagName == null) throw new ArgumentNullException(nameof(tagName));
-            NbtTag tempResult;
+            NbtTag? tempResult;
             if (tags.TryGetValue(tagName, out tempResult)) {
                 result = tempResult;
                 return true;
@@ -188,7 +188,7 @@ public bool Contains(string tagName) {
         /// <exception cref="ArgumentNullException"> <paramref name="tagName"/> is <c>null</c>. </exception>
         public bool Remove(string tagName) {
             if (tagName == null) throw new ArgumentNullException(nameof(tagName));
-            NbtTag tag;
+            NbtTag? tag;
             if (!tags.TryGetValue(tagName, out tag)) {
                 return false;
             }
@@ -467,7 +467,7 @@ public void CopyTo(NbtTag[] array, int arrayIndex) {
         public bool Remove(NbtTag tag) {
             if (tag == null) throw new ArgumentNullException(nameof(tag));
             if (tag.Name == null) throw new ArgumentException("Trying to remove an unnamed tag.");
-            NbtTag maybeItem;
+            NbtTag? maybeItem;
             if (tags.TryGetValue(tag.Name, out maybeItem)) {
                 if (maybeItem == tag && tags.Remove(tag.Name)) {
                     tag.Parent = null;

fNbt/Tags/NbtList.cs

@@ -481,35 +481,35 @@ bool ICollection<NbtTag>.IsReadOnly {
 
         #region Implementation of IList and ICollection
 
-        void IList.Remove(object value) {
-            Remove((NbtTag)value);
+        void IList.Remove(object? value) {
+            Remove((NbtTag)value!);
         }
 
 
-        object IList.this[int tagIndex] {
+        object? IList.this[int tagIndex] {
             get { return tags[tagIndex]; }
-            set { this[tagIndex] = (NbtTag)value; }
+            set { this[tagIndex] = (NbtTag)value!; }
         }
 
 
-        int IList.Add(object value) {
-            Add((NbtTag)value);
+        int IList.Add(object? value) {
+            Add((NbtTag)value!);
             return (tags.Count - 1);
         }
 
 
-        bool IList.Contains(object value) {
-            return tags.Contains((NbtTag)value);
+        bool IList.Contains(object? value) {
+            return tags.Contains((NbtTag)value!);
         }
 
 
-        int IList.IndexOf(object value) {
-            return tags.IndexOf((NbtTag)value);
+        int IList.IndexOf(object? value) {
+            return tags.IndexOf((NbtTag)value!);
         }
 
 
-        void IList.Insert(int index, object value) {
-            Insert(index, (NbtTag)value);
+        void IList.Insert(int index, object? value) {
+            Insert(index, (NbtTag)value!);
         }
 
 

fNbt/Tags/NbtTag.cs

@@ -81,6 +81,7 @@ public string Path {
 
 
         #region Shortcuts
+#pragma warning disable CA1065 // Do not raise exceptions in unexpected locations
 
         /// <summary> Gets or sets the tag with the specified name. May return <c>null</c>. </summary>
         /// <returns> The tag with the specified key. Null if tag with the given name was not found. </returns>
@@ -287,7 +288,7 @@ public string StringValue {
                 }
             }
         }
-
+#pragma warning restore CA1065 // Do not raise exceptions in unexpected locations
         #endregion