Reflection annotate more of CoreLib (#37418)

src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs

@@ -26,6 +26,8 @@ public static partial class Marshal
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern int SizeOfHelper(Type t, bool throwIfNotMarshalable);
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Trimming doesn't affect types eligible for marshalling. Different exception for invalid inputs doesn't matter.")]
         public static IntPtr OffsetOf(Type t, string fieldName)
         {
             if (t is null)

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

@@ -3779,6 +3779,8 @@ private void CreateInstanceCheckThis()
                 throw new NotSupportedException(SR.Acc_CreateVoid);
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Implementation detail of Activator that linker intrinsically recognizes")]
         internal object? CreateInstanceImpl(
             BindingFlags bindingAttr, Binder? binder, object?[]? args, CultureInfo? culture)
         {

src/coreclr/src/System.Private.CoreLib/src/System/ValueType.cs

@@ -11,6 +11,7 @@
 **
 ===========================================================*/
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
@@ -20,6 +21,8 @@ namespace System
     [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public abstract class ValueType
     {
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Trimmed fields don't make a difference for equality")]
         public override bool Equals(object? obj)
         {
             if (null == obj)

src/libraries/System.Private.CoreLib/src/System/Activator.RuntimeType.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Globalization;
 using System.Runtime.Loader;
@@ -97,6 +98,8 @@ public static partial class Activator
             throw new ArgumentException(SR.Arg_MustBeType, nameof(type));
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Implementation detail of Activator that linker intrinsically recognizes")]
         private static ObjectHandle? CreateInstanceInternal(string assemblyString,
                                                            string typeName,
                                                            bool ignoreCase,

src/libraries/System.Private.CoreLib/src/System/Activator.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Reflection;
 using System.Runtime.Remoting;
@@ -40,12 +41,15 @@ public static partial class Activator
         public static object? CreateInstance(Type type) =>
             CreateInstance(type, nonPublic: false);
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public static ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName) =>
             CreateInstanceFrom(assemblyFile, typeName, false, ConstructorDefault, null, null, null, null);
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public static ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName, object?[]? activationAttributes) =>
             CreateInstanceFrom(assemblyFile, typeName, false, ConstructorDefault, null, null, null, activationAttributes);
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public static ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName, bool ignoreCase, BindingFlags bindingAttr, Binder? binder, object?[]? args, CultureInfo? culture, object?[]? activationAttributes)
         {
             Assembly assembly = Assembly.LoadFrom(assemblyFile);

src/libraries/System.Private.CoreLib/src/System/AppDomain.cs

@@ -5,6 +5,7 @@
 #pragma warning disable CS0067 // events are declared but not used
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Reflection;
 using System.Runtime.CompilerServices;
@@ -278,6 +279,7 @@ public void SetThreadPrincipal(IPrincipal principal)
             }
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstance(string assemblyName, string typeName)
         {
             if (assemblyName == null)
@@ -288,6 +290,7 @@ public void SetThreadPrincipal(IPrincipal principal)
             return Activator.CreateInstance(assemblyName, typeName);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstance(string assemblyName, string typeName, bool ignoreCase, BindingFlags bindingAttr, Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes)
         {
             if (assemblyName == null)
@@ -305,6 +308,7 @@ public void SetThreadPrincipal(IPrincipal principal)
                                             activationAttributes);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstance(string assemblyName, string typeName, object?[]? activationAttributes)
         {
             if (assemblyName == null)
@@ -315,12 +319,14 @@ public void SetThreadPrincipal(IPrincipal principal)
             return Activator.CreateInstance(assemblyName, typeName, activationAttributes);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceAndUnwrap(string assemblyName, string typeName)
         {
             ObjectHandle? oh = CreateInstance(assemblyName, typeName);
             return oh?.Unwrap();
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceAndUnwrap(string assemblyName, string typeName, bool ignoreCase, BindingFlags bindingAttr, Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes)
         {
             ObjectHandle? oh = CreateInstance(assemblyName,
@@ -334,17 +340,20 @@ public void SetThreadPrincipal(IPrincipal principal)
             return oh?.Unwrap();
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceAndUnwrap(string assemblyName, string typeName, object?[]? activationAttributes)
         {
             ObjectHandle? oh = CreateInstance(assemblyName, typeName, activationAttributes);
             return oh?.Unwrap();
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName)
         {
             return Activator.CreateInstanceFrom(assemblyFile, typeName);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName, bool ignoreCase, BindingFlags bindingAttr, Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes)
         {
             return Activator.CreateInstanceFrom(assemblyFile,
@@ -357,17 +366,20 @@ public void SetThreadPrincipal(IPrincipal principal)
                                                 activationAttributes);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public ObjectHandle? CreateInstanceFrom(string assemblyFile, string typeName, object?[]? activationAttributes)
         {
             return Activator.CreateInstanceFrom(assemblyFile, typeName, activationAttributes);
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceFromAndUnwrap(string assemblyFile, string typeName)
         {
             ObjectHandle? oh = CreateInstanceFrom(assemblyFile, typeName);
             return oh?.Unwrap();
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceFromAndUnwrap(string assemblyFile, string typeName, bool ignoreCase, BindingFlags bindingAttr, Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes)
         {
             ObjectHandle? oh = CreateInstanceFrom(assemblyFile,
@@ -381,6 +393,7 @@ public void SetThreadPrincipal(IPrincipal principal)
             return oh?.Unwrap();
         }
 
+        [RequiresUnreferencedCode("Type and its constructor could be removed")]
         public object? CreateInstanceFromAndUnwrap(string assemblyFile, string typeName, object?[]? activationAttributes)
         {
             ObjectHandle? oh = CreateInstanceFrom(assemblyFile, typeName, activationAttributes);

src/libraries/System.Private.CoreLib/src/System/Attribute.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace System
@@ -15,6 +16,8 @@ public abstract partial class Attribute
         protected Attribute() { }
 
 #if !CORERT
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Unused fields don't make a difference for equality")]
         public override bool Equals(object? obj)
         {
             if (obj == null)
@@ -47,6 +50,8 @@ public override bool Equals(object? obj)
             return true;
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Unused fields don't make a difference for hashcode quality")]
         public override int GetHashCode()
         {
             Type type = GetType();

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

@@ -509,6 +509,8 @@ public static void Prelink(MethodInfo m)
             PrelinkCore(m);
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "This only needs to prelink methods that are actually used")]
         public static void PrelinkAll(Type c)
         {
             if (c is null)
@@ -533,7 +535,9 @@ public static void StructureToPtr<T>([DisallowNull] T structure, IntPtr ptr, boo
         /// Creates a new instance of "structuretype" and marshals data from a
         /// native memory block to it.
         /// </summary>
-        public static object? PtrToStructure(IntPtr ptr, Type structureType)
+        public static object? PtrToStructure(IntPtr ptr,
+            [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)]
+            Type structureType)
         {
             if (ptr == IntPtr.Zero)
             {

src/libraries/System.Private.CoreLib/src/System/Type.Enum.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Collections;
 using System.Collections.Generic;
@@ -105,6 +106,8 @@ private Array GetEnumRawConstantValues()
             return values;
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Literal fields on enums can never be trimmed")]
         // This will return enumValues and enumNames sorted by the values.
         private void GetEnumData(out string[] enumNames, out Array enumValues)
         {

src/libraries/System.Private.CoreLib/src/System/Type.cs

@@ -149,6 +149,8 @@ public ConstructorInfo? TypeInitializer
         protected abstract ConstructorInfo? GetConstructorImpl(BindingFlags bindingAttr, Binder? binder, CallingConventions callConvention, Type[] types, ParameterModifier[]? modifiers);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetConstructors(BindingFlags.Public) but this is what the body is doing")]
         public ConstructorInfo[] GetConstructors() => GetConstructors(BindingFlags.Public | BindingFlags.Instance);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
@@ -161,6 +163,8 @@ public ConstructorInfo? TypeInitializer
         public abstract EventInfo? GetEvent(string name, BindingFlags bindingAttr);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicEvents)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetEvents(BindingFlags.Public) but this is what the body is doing")]
         public virtual EventInfo[] GetEvents() => GetEvents(Type.DefaultLookup);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicEvents | DynamicallyAccessedMemberTypes.NonPublicEvents)]
@@ -173,16 +177,26 @@ public ConstructorInfo? TypeInitializer
         public abstract FieldInfo? GetField(string name, BindingFlags bindingAttr);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetFields(BindingFlags.Public) but this is what the body is doing")]
         public FieldInfo[] GetFields() => GetFields(Type.DefaultLookup);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)]
         public abstract FieldInfo[] GetFields(BindingFlags bindingAttr);
 
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         public MemberInfo[] GetMember(string name) => GetMember(name, Type.DefaultLookup);
+
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         public virtual MemberInfo[] GetMember(string name, BindingFlags bindingAttr) => GetMember(name, MemberTypes.All, bindingAttr);
+
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         public virtual MemberInfo[] GetMember(string name, MemberTypes type, BindingFlags bindingAttr) => throw new NotSupportedException(SR.NotSupported_SubclassOverride);
 
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         public MemberInfo[] GetMembers() => GetMembers(Type.DefaultLookup);
+
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         public abstract MemberInfo[] GetMembers(BindingFlags bindingAttr);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
@@ -253,6 +267,8 @@ public ConstructorInfo? TypeInitializer
         protected virtual MethodInfo? GetMethodImpl(string name, int genericParameterCount, BindingFlags bindingAttr, Binder? binder, CallingConventions callConvention, Type[]? types, ParameterModifier[]? modifiers) => throw new NotSupportedException();
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetMethods(BindingFlags.Public) but this is what the body is doing")]
         public MethodInfo[] GetMethods() => GetMethods(Type.DefaultLookup);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.NonPublicMethods)]
@@ -265,6 +281,8 @@ public ConstructorInfo? TypeInitializer
         public abstract Type? GetNestedType(string name, BindingFlags bindingAttr);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicNestedTypes)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetNestedTypes(BindingFlags.Public) but this is what the body is doing")]
         public Type[] GetNestedTypes() => GetNestedTypes(Type.DefaultLookup);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicNestedTypes | DynamicallyAccessedMemberTypes.NonPublicNestedTypes)]
@@ -282,6 +300,8 @@ public ConstructorInfo? TypeInitializer
         }
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetPropertyImpl(BindingFlags.Public) but this is what the body is doing")]
         public PropertyInfo? GetProperty(string name, Type? returnType)
         {
             if (name == null)
@@ -312,6 +332,8 @@ public ConstructorInfo? TypeInitializer
         protected abstract PropertyInfo? GetPropertyImpl(string name, BindingFlags bindingAttr, Binder? binder, Type? returnType, Type[]? types, ParameterModifier[]? modifiers);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "Linker doesn't recongnize GetProperties(BindingFlags.Public) but this is what the body is doing")]
         public PropertyInfo[] GetProperties() => GetProperties(Type.DefaultLookup);
 
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties | DynamicallyAccessedMemberTypes.NonPublicProperties)]
@@ -392,6 +414,8 @@ protected virtual TypeCode GetTypeCodeImpl()
         public virtual bool IsInstanceOfType([NotNullWhen(true)] object? o) => o == null ? false : IsAssignableFrom(o.GetType());
         public virtual bool IsEquivalentTo([NotNullWhen(true)] Type? other) => this == other;
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2006:UnrecognizedReflectionPattern",
+            Justification = "The single instance field on enum types is never trimmed")]
         public virtual Type GetEnumUnderlyingType()
         {
             if (!IsEnum)