Incorporating FB

src/libraries/System.Private.CoreLib/src/System/Diagnostics/CodeAnalysis/RequiresDynamicCodeAttribute.cs

@@ -10,7 +10,7 @@ namespace System.Diagnostics.CodeAnalysis
     /// <remarks>
     /// This allows tools to understand which methods are unsafe to call when compiling ahead of time.
     /// </remarks>
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Constructor, Inherited = false)]
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Constructor | AttributeTargets.Class, Inherited = false)]
     public sealed class RequiresDynamicCodeAttribute : Attribute
     {
         /// <summary>

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -7458,7 +7458,7 @@ public RequiresAssemblyFilesAttribute(string message) { }
         public string? Message { get { throw null; } }
         public string? Url { get { throw null; } set { } }
     }
-    [System.AttributeUsageAttribute(System.AttributeTargets.Constructor | System.AttributeTargets.Method, Inherited=false)]
+    [System.AttributeUsageAttribute(System.AttributeTargets.Constructor | System.AttributeTargets.Method | AttributeTargets.Class, Inherited=false)]
     public sealed partial class RequiresDynamicCodeAttribute : System.Attribute
     {
         public RequiresDynamicCodeAttribute(string message) { }

src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Regex.cs

@@ -74,6 +74,8 @@ internal Regex(string pattern, CultureInfo? culture)
             // if no options are ever used.
         }
 
+        [UnconditionalSuppressMessage("AotAnalysis", "IL3050:RequiresDynamicCode",
+            Justification = "Native AOT does not use compiled Regex")]
         internal Regex(string pattern, RegexOptions options, TimeSpan matchTimeout, CultureInfo? culture)
         {
             // Validate arguments.
@@ -201,6 +203,7 @@ protected IDictionary? CapNames
         /// Regex constructor, we don't load RegexCompiler and its reflection classes when
         /// instantiating a non-compiled regex.
         /// </summary>
+        [RequiresDynamicCode("The native code for Regex compilation might not be available at runtime.")]
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static RegexRunnerFactory? Compile(string pattern, RegexTree regexTree, RegexOptions options, bool hasTimeout) =>
             RegexCompiler.Compile(pattern, regexTree, options, hasTimeout);

src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCompiler.cs

@@ -15,8 +15,7 @@ namespace System.Text.RegularExpressions
     /// <summary>
     /// RegexCompiler translates a block of RegexCode to MSIL, and creates a subclass of the RegexRunner type.
     /// </summary>
-    [UnconditionalSuppressMessage("AotAnalysis", "IL3050:RequiresDynamicCode",
-        Justification = "Native AOT does not use compiled Regex")]
+    [RequiresDynamicCode("The native code for Regex compilation might not be available at runtime.")]
     internal abstract class RegexCompiler
     {
         private static readonly FieldInfo s_runtextstartField = RegexRunnerField("runtextstart");

src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexLWCGCompiler.cs

@@ -31,6 +31,7 @@ internal sealed class RegexLWCGCompiler : RegexCompiler
         private static int s_regexCount;
 
         /// <summary>The top-level driver. Initializes everything then calls the Generate* methods.</summary>
+        [RequiresDynamicCode("The native code for Regex compilation might not be available at runtime.")]
         public RegexRunnerFactory? FactoryInstanceFromCode(string pattern, RegexTree regexTree, RegexOptions options, bool hasTimeout)
         {
             if (!regexTree.Root.SupportsCompilation(out _))
@@ -66,8 +67,7 @@ internal sealed class RegexLWCGCompiler : RegexCompiler
         }
 
         /// <summary>Begins the definition of a new method (no args) with a specified return value.</summary>
-        [UnconditionalSuppressMessage("AotAnalysis", "IL3050:RequiresDynamicCode",
-            Justification = "Native AOT does not use compiled Regex")]
+        [RequiresDynamicCode("The native code for Regex compilation might not be available at runtime.")]
         private DynamicMethod DefineDynamicMethod(string methname, Type? returntype, Type hostType, Type[] paramTypes)
         {
             // We're claiming that these are static methods, but really they are instance methods.