Address PR feedback: move comment, remove FIXME from Array.CoreCLR.cs, refactor Delegate.CoreCLR.cs, add clarifying comments

Co-authored-by: agocke <[email protected]>

Author: Copilot

src/coreclr/System.Private.CoreLib/src/System/Array.CoreCLR.cs

@@ -402,7 +402,6 @@ internal IEnumerator<T> GetEnumerator<T>()
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -417,7 +416,6 @@ private void CopyTo<T>(T[] array, int index)
             // ! or you may introduce a security hole!
 
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -430,7 +428,6 @@ internal int get_Count<T>()
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -443,7 +440,6 @@ internal T get_Item<T>(int index)
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -461,7 +457,6 @@ internal void set_Item<T>(int index, T value)
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -485,7 +480,6 @@ private bool Contains<T>(T value)
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);
@@ -511,7 +505,6 @@ private int IndexOf<T>(T value)
             // ! Warning: "this" is an array, not an SZArrayHelper. See comments above
             // ! or you may introduce a security hole!
             T[] @this;
-            // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
                 @this = Unsafe.As<T[]>(this);

src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

@@ -435,13 +435,11 @@ private bool BindToMethodInfo(object? target, IRuntimeMethodInfo method, Runtime
         private static MulticastDelegate InternalAlloc(RuntimeType type)
         {
             Debug.Assert(type.IsAssignableTo(typeof(MulticastDelegate)));
-            MulticastDelegate result;
             // FIXME: review unsafe to confirm correct annotation
             unsafe
             {
-                result = Unsafe.As<MulticastDelegate>(RuntimeTypeHandle.InternalAlloc(type));
+                return Unsafe.As<MulticastDelegate>(RuntimeTypeHandle.InternalAlloc(type));
             }
-            return result;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/ConfiguredValueTaskAwaitable.cs

@@ -60,6 +60,7 @@ public void OnCompleted(Action continuation)
                 }
                 else if (obj != null)
                 {
+                    // obj is either Task, null, or IValueTaskSource and the other cases are checked
                     IValueTaskSource source;
                     unsafe
                     {
@@ -87,6 +88,7 @@ public void UnsafeOnCompleted(Action continuation)
                 }
                 else if (obj != null)
                 {
+                    // obj is either Task, null, or IValueTaskSource and the other cases are checked
                     IValueTaskSource source;
                     unsafe
                     {
@@ -112,6 +114,7 @@ void IStateMachineBoxAwareAwaiter.AwaitUnsafeOnCompleted(IAsyncStateMachineBox b
                 }
                 else if (obj != null)
                 {
+                    // obj is either Task, null, or IValueTaskSource and the other cases are checked
                     IValueTaskSource source;
                     unsafe
                     {

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/MemoryMarshal.cs

@@ -285,13 +285,13 @@ public static bool TryGetArray<T>(ReadOnlyMemory<T> memory, out ArraySegment<T>
                     // or a U[] which is blittable to a T[] (e.g., int[] and uint[]).
 
                     // The array may be prepinned, so remove the high bit from the start index in the line below.
-                    // The ArraySegment<T> ctor will perform bounds checking on index & length.
 
                     T[] array;
                     unsafe
                     {
                         array = Unsafe.As<T[]>(obj);
                     }
+                    // The ArraySegment<T> ctor will perform bounds checking on index & length.
                     segment = new ArraySegment<T>(array, index & ReadOnlyMemory<T>.RemoveFlagsBitMask, length);
                     return true;
                 }