Document breaking change: Replace DAMT.All with restricted annotations on reflection APIs

docs/core/compatibility/10.0.md

@@ -53,6 +53,7 @@ If you're migrating an app to .NET 10, the breaking changes listed here might af
 | [LDAP DirectoryControl parsing is now more stringent](core-libraries/10.0/ldap-directorycontrol-parsing.md) | Behavioral change | Preview 1 |
 | [MacCatalyst version normalization](core-libraries/10.0/maccatalyst-version-normalization.md) | Behavioral change | Preview 1 |
 | [.NET runtime no longer provides default termination signal handlers](core-libraries/10.0/sigterm-signal-handler.md) | Behavioral change | Preview 5 |
+| [Replace DAMT.All with more restricted annotation on InvokeMember/FindMembers/DeclaredMembers](reflection/10/damt-all-restricted-annotations.md) | Source incompatible/behavioral change | Preview 1 |
 | [System.Linq.AsyncEnumerable included in core libraries](core-libraries/10.0/asyncenumerable.md) | Source incompatible | Preview 1 |
 | [Type.MakeGenericSignatureType argument validation](reflection/10/makegeneric-signaturetype-validation.md) | Behavioral change | Preview 3 |
 | [YMM embedded rounding removed from AVX10.2](core-libraries/10.0/ymm-embedded-rounding.md) | Behavioral change | Preview 5 |

docs/core/compatibility/reflection/10/damt-all-restricted-annotations.md

@@ -0,0 +1,94 @@
+---
+title: "Breaking change: Replace DAMT.All with more restricted annotation on InvokeMember/FindMembers/DeclaredMembers"
+description: Learn about the .NET 10 breaking change in core .NET libraries where InvokeMember, FindMembers, and DeclaredMembers APIs use more restricted annotations instead of DAMT.All.
+ms.date: 10/22/2025
+ai-usage: ai-assisted
+---
+# Replace DAMT.All with more restricted annotation on InvokeMember/FindMembers/DeclaredMembers
+
+Starting in .NET 10, the <xref:System.Reflection.IReflect.InvokeMember%2A?displayProperty=nameWithType>, <xref:System.Type.FindMembers%2A?displayProperty=nameWithType>, and <xref:System.Reflection.TypeInfo.DeclaredMembers?displayProperty=nameWithType> APIs use more restricted annotations instead of `DAMT.All`. This change affects scenarios where you implement the <xref:System.Reflection.IReflect> interface or derive from <xref:System.Reflection.TypeInfo>.
+
+## Version introduced
+
+.NET 10 Preview 1
+
+## Previous behavior
+
+Previously, the `InvokeMember`, `FindMembers`, and `DeclaredMembers` APIs used the `DAMT.All` annotation, which was overly permissive. This could result in capturing additional members, such as interface methods implemented by a class, and potentially caused runtime warnings or unsafe reflection calls.
+
+```csharp
+public class MyType : IReflect
+{
+    public MethodInfo[] GetMethods(BindingFlags bindingAttr)
+    {
+        // Previous behavior: DAMT.All annotation applied
+        // This could capture additional members, including interface methods implemented by the class
+    }
+}
+```
+
+## New behavior
+
+The `InvokeMember`, `FindMembers`, and `DeclaredMembers` APIs now use more restricted annotations, which provide better control over the members captured during reflection. You must update your annotations to match the new behavior if you implement <xref:System.Reflection.IReflect> or derive from <xref:System.Reflection.TypeInfo>.
+
+```csharp
+public class MyType : IReflect
+{
+    [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
+    public MethodInfo[] GetMethods(BindingFlags bindingAttr)
+    {
+        // New behavior: More restricted annotation applied
+        // Only public methods are captured, avoiding unintended members
+    }
+}
+```
+
+## Type of breaking change
+
+This change can affect [source compatibility](../../categories.md#source-incompatible) and is a [behavioral change](../../categories.md#behavioral-change).
+
+## Reason for change
+
+The change was introduced to improve the accuracy of annotations in <xref:System.Reflection> APIs and to address issues caused by the overly permissive `DAMT.All` annotation. This ensures better compatibility with trimming and reflection scenarios, reduces runtime warnings, and prevents unsafe reflection calls.
+
+## Recommended action
+
+If you implement <xref:System.Reflection.IReflect> or derive from <xref:System.Reflection.TypeInfo>, review your code and update annotations to align with the new behavior. Specifically:
+
+1. Replace `DAMT.All` annotations with more restricted annotations, such as <xref:System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicMethods?displayProperty=nameWithType>, <xref:System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.NonPublicMethods?displayProperty=nameWithType>, or other appropriate types.
+1. Test reflection scenarios to ensure that the updated annotations capture the intended members and don't introduce runtime errors or warnings.
+
+**Before:**
+
+```csharp
+public class MyType : IReflect
+{
+    public MethodInfo[] GetMethods(BindingFlags bindingAttr)
+    {
+        // Previous behavior: DAMT.All annotation applied
+    }
+}
+```
+
+**After:**
+
+```csharp
+public class MyType : IReflect
+{
+    [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
+    public MethodInfo[] GetMethods(BindingFlags bindingAttr)
+    {
+        // New behavior: More restricted annotation applied
+    }
+}
+```
+
+## Affected APIs
+
+- <xref:System.Reflection.IReflect.InvokeMember%2A?displayProperty=fullName>
+- <xref:System.Type.FindMembers%2A?displayProperty=fullName>
+- <xref:System.Reflection.TypeInfo.DeclaredMembers?displayProperty=fullName>
+
+## See also
+
+- [Prepare .NET libraries for trimming](/dotnet/core/deploying/trimming/prepare-libraries-for-trimming)

docs/core/compatibility/toc.yml

@@ -116,6 +116,8 @@ items:
                 href: networking/10.0/uri-length-limits-removed.md
           - name: Reflection
             items:
+              - name: Replace DAMT.All with more restricted annotation on InvokeMember/FindMembers/DeclaredMembers
+                href: reflection/10/damt-all-restricted-annotations.md
               - name: Type.MakeGenericSignatureType argument validation
                 href: reflection/10/makegeneric-signaturetype-validation.md
           - name: SDK and MSBuild