From 5a291c7adba61aaf26acab09f025ad298471bbc9 Mon Sep 17 00:00:00 2001
From: xtqqczze <45661989+xtqqczze@users.noreply.github.com>
Date: Fri, 19 Sep 2025 17:31:45 +0100
Subject: [PATCH] Update comments for CA1825 suppression

Update comments for CA1825: Avoid zero-length array allocations

It is not correct that `Array.Empty<T>()` doesn't exist in all configurations, the API is available from .NET Standard 1.3.
---
 .../System/Collections/Immutable/ImmutableArray_1.Minimal.cs  | 4 +---
 .../src/System/Diagnostics/Activity.cs                        | 4 ++--
 .../src/System/Threading/ExecutionContext.cs                  | 2 +-
 .../src/Internal/ImmutableArray.cs                            | 2 +-
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray_1.Minimal.cs b/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray_1.Minimal.cs
index 9ef57a400ed50c..48dfacfe063eb6 100644
--- a/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray_1.Minimal.cs
+++ b/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray_1.Minimal.cs
@@ -38,9 +38,7 @@ public partial struct ImmutableArray<T> : IEnumerable<T>, IEquatable<ImmutableAr
         /// <summary>
         /// An empty (initialized) instance of <see cref="ImmutableArray{T}"/>.
         /// </summary>
-#pragma warning disable CA1825
-        // Array.Empty<T>() doesn't exist in all configurations
-        // Switching to Array.Empty also has a non-negligible impact on the working set memory
+#pragma warning disable CA1825 // avoid the extra generic instantiation for Array.Empty<T>()
         public static readonly ImmutableArray<T> Empty = new ImmutableArray<T>(new T[0]);
 #pragma warning restore CA1825
 
diff --git a/src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs b/src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs
index 65274673caf8c5..ff56580b155f22 100644
--- a/src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs
+++ b/src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs
@@ -55,12 +55,12 @@ internal ActivityChangedEventArgs(Activity? previous, Activity? current)
     /// </summary>
     public partial class Activity : IDisposable
     {
-#pragma warning disable CA1825 // Array.Empty<T>() doesn't exist in all configurations
+#pragma warning disable CA1825 // avoid the extra generic instantiation for Array.Empty<T>()
         private static readonly IEnumerable<KeyValuePair<string, string?>> s_emptyBaggageTags = new KeyValuePair<string, string?>[0];
         private static readonly IEnumerable<KeyValuePair<string, object?>> s_emptyTagObjects = new KeyValuePair<string, object?>[0];
+#pragma warning restore CA1825
         private static readonly IEnumerable<ActivityLink> s_emptyLinks = new DiagLinkedList<ActivityLink>();
         private static readonly IEnumerable<ActivityEvent> s_emptyEvents = new DiagLinkedList<ActivityEvent>();
-#pragma warning restore CA1825
         private static readonly ActivitySource s_defaultSource = new ActivitySource(string.Empty);
         private static readonly AsyncLocal<Activity?> s_current = new AsyncLocal<Activity?>();
 
diff --git a/src/libraries/System.Private.CoreLib/src/System/Threading/ExecutionContext.cs b/src/libraries/System.Private.CoreLib/src/System/Threading/ExecutionContext.cs
index affc292913fcf5..e160e0d748956c 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Threading/ExecutionContext.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Threading/ExecutionContext.cs
@@ -85,7 +85,7 @@ public void GetObjectData(SerializationInfo info, StreamingContext context)
 
             if (m_localValues == null || AsyncLocalValueMap.IsEmpty(m_localValues))
             {
-#pragma warning disable CA1825, IDE0300 // Avoid unnecessary zero-length array allocations
+#pragma warning disable CA1825, IDE0300 // avoid the extra generic instantiation for Array.Empty<T>()
                 return isFlowSuppressed ?
                     (s_defaultFlowSuppressed ??= new ExecutionContext(AsyncLocalValueMap.Empty, new IAsyncLocal[0], isFlowSuppressed: true)) :
                     null; // implies the default context
diff --git a/src/libraries/System.Threading.Tasks.Dataflow/src/Internal/ImmutableArray.cs b/src/libraries/System.Threading.Tasks.Dataflow/src/Internal/ImmutableArray.cs
index 432ec82566dc55..c2ac5e6117da0c 100644
--- a/src/libraries/System.Threading.Tasks.Dataflow/src/Internal/ImmutableArray.cs
+++ b/src/libraries/System.Threading.Tasks.Dataflow/src/Internal/ImmutableArray.cs
@@ -25,7 +25,7 @@ namespace System.Threading.Tasks.Dataflow.Internal
     internal readonly struct ImmutableArray<T>
     {
         /// <summary>An empty array.</summary>
-#pragma warning disable CA1825 // Array.Empty<T>() doesn't exist in all configurations
+#pragma warning disable CA1825 // avoid the extra generic instantiation for Array.Empty<T>()
         private static readonly ImmutableArray<T> s_empty = new ImmutableArray<T>(new T[0]);
 #pragma warning restore CA1825
         /// <summary>The immutable data in this array instance.</summary>