Annotate System.Linq.Expressions with RequiresDynamicCode (#90456)

* Annotate System.Linq.Expressions with RequiresDynamicCode

All this ended up with an RUC on Expression.Compile due to new arrays.
I could potentially silence this warning with a feature flag, but it is a
real risk, and one that users could maybe work around if alterted to the

Co-authored-by: Eric Erhardt <eric.erhardt@microsoft.com>
Co-authored-by: Stephen Toub <stoub@microsoft.com>

src/libraries/Common/tests/TestUtilities/System/AssertExtensions.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
@@ -15,6 +16,26 @@ public static class AssertExtensions
     {
         private static bool IsNetFramework => RuntimeInformation.FrameworkDescription.StartsWith(".NET Framework");
 
+
+        /// <summary>
+        /// Helper for AOT tests that verifies that the compile succeeds, or throws PlatformNotSupported
+        /// when AOT is enabled.
+        /// </summary>
+        public static void ThrowsOnAot<T>(Action action)
+            where T : Exception
+        {
+#if NETCOREAPP // Dynamic code is always supported on .NET Framework
+            if (!RuntimeFeature.IsDynamicCodeSupported)
+            {
+                Assert.Throws<T>(action);
+            }
+            else
+#endif
+            {
+                action();
+            }
+        }
+
         public static void Throws<T>(Action action, string expectedMessage)
             where T : Exception
         {

src/libraries/Microsoft.Extensions.DependencyInjection/src/ServiceLookup/Expressions/ExpressionResolverBuilder.cs

@@ -123,14 +123,23 @@ static MethodInfo GetArrayEmptyMethodInfo(Type elementType)
                 return ServiceLookupHelpers.GetArrayEmptyMethodInfo(elementType);
             }
 
+            [UnconditionalSuppressMessage("AotAnalysis", "IL3050:RequiresDynamicCode",
+                Justification = "VerifyAotCompatibility ensures elementType is not a ValueType")]
+            static NewArrayExpression NewArrayInit(Type elementType, IEnumerable<Expression> expr)
+            {
+                Debug.Assert(!ServiceProvider.VerifyAotCompatibility || !elementType.IsValueType, "VerifyAotCompatibility=true will throw during building the IEnumerableCallSite if elementType is a ValueType.");
+
+                return Expression.NewArrayInit(elementType, expr);
+            }
+
             if (callSite.ServiceCallSites.Length == 0)
             {
                 return Expression.Constant(
                     GetArrayEmptyMethodInfo(callSite.ItemType)
                     .Invoke(obj: null, parameters: Array.Empty<object>()));
             }
 
-            return Expression.NewArrayInit(
+            return NewArrayInit(
                 callSite.ItemType,
                 callSite.ServiceCallSites.Select(cs =>
                     Convert(

src/libraries/System.Linq.Expressions/ref/System.Linq.Expressions.cs

@@ -607,9 +607,13 @@ protected Expression(System.Linq.Expressions.ExpressionType nodeType, System.Typ
         public static System.Linq.Expressions.NewExpression New(System.Reflection.ConstructorInfo constructor, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression>? arguments, params System.Reflection.MemberInfo[]? members) { throw null; }
         public static System.Linq.Expressions.NewExpression New(System.Reflection.ConstructorInfo constructor, params System.Linq.Expressions.Expression[]? arguments) { throw null; }
         public static System.Linq.Expressions.NewExpression New([System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.NonPublicConstructors | System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type type) { throw null; }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Creating arrays at runtime requires dynamic code generation.")]
         public static System.Linq.Expressions.NewArrayExpression NewArrayBounds(System.Type type, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression> bounds) { throw null; }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Creating arrays at runtime requires dynamic code generation.")]
         public static System.Linq.Expressions.NewArrayExpression NewArrayBounds(System.Type type, params System.Linq.Expressions.Expression[] bounds) { throw null; }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Creating arrays at runtime requires dynamic code generation.")]
         public static System.Linq.Expressions.NewArrayExpression NewArrayInit(System.Type type, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression> initializers) { throw null; }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Creating arrays at runtime requires dynamic code generation.")]
         public static System.Linq.Expressions.NewArrayExpression NewArrayInit(System.Type type, params System.Linq.Expressions.Expression[] initializers) { throw null; }
         public static System.Linq.Expressions.UnaryExpression Not(System.Linq.Expressions.Expression expression) { throw null; }
         public static System.Linq.Expressions.UnaryExpression Not(System.Linq.Expressions.Expression expression, System.Reflection.MethodInfo? method) { throw null; }
@@ -1028,6 +1032,7 @@ internal MethodCallExpression() { }
         System.Linq.Expressions.Expression System.Linq.Expressions.IArgumentProvider.GetArgument(int index) { throw null; }
         public System.Linq.Expressions.MethodCallExpression Update(System.Linq.Expressions.Expression? @object, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression>? arguments) { throw null; }
     }
+    [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Creating arrays at runtime requires dynamic code generation.")]
     public partial class NewArrayExpression : System.Linq.Expressions.Expression
     {
         internal NewArrayExpression() { }

src/libraries/System.Linq.Expressions/src/CompatibilitySuppressions.xml

@@ -97,6 +97,48 @@
     <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
     <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.Call(System.Linq.Expressions.Expression,System.String,System.Type[],System.Linq.Expressions.Expression[]):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.Call(System.Type,System.String,System.Type[],System.Linq.Expressions.Expression[]):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.ListInit(System.Linq.Expressions.NewExpression,System.Collections.Generic.IEnumerable{System.Linq.Expressions.Expression}):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.ListInit(System.Linq.Expressions.NewExpression,System.Linq.Expressions.Expression[]):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.ListInit(System.Linq.Expressions.NewExpression,System.Reflection.MethodInfo,System.Collections.Generic.IEnumerable{System.Linq.Expressions.Expression}):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Linq.Expressions.Expression.ListInit(System.Linq.Expressions.NewExpression,System.Reflection.MethodInfo,System.Linq.Expressions.Expression[]):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0016</DiagnosticId>
+    <Target>M:System.Runtime.CompilerServices.CallSite`1.Create(System.Runtime.CompilerServices.CallSiteBinder):[T:System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute]</Target>
+    <Left>ref/net8.0/System.Linq.Expressions.dll</Left>
+    <Right>lib/net8.0/System.Linq.Expressions.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0020</DiagnosticId>
     <Target>M:System.Linq.Expressions.DynamicExpressionVisitor.#ctor</Target>

src/libraries/System.Linq.Expressions/src/Resources/Strings.resx

@@ -564,4 +564,7 @@
   <data name="Arg_KeyNotFoundWithKey" xml:space="preserve">
     <value>The given key '{0}' was not present in the dictionary.</value>
   </data>
+  <data name="LiftingInExpressionRequiresDynamicCode" xml:space="preserve">
+    <value>Nullable lifting on non-primitive type '{0}' is only supported in expression trees when dynamic code generation is available.</value>
+  </data>
 </root>

src/libraries/System.Linq.Expressions/src/System.Linq.Expressions.csproj

@@ -3,7 +3,6 @@
     <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
     <DefineConstants> $(DefineConstants);FEATURE_FAST_CREATE</DefineConstants>
     <NoWarn>$(NoWarn);CA1859</NoWarn>
-    <EnableAOTAnalyzer>false</EnableAOTAnalyzer>
     <!--
       Disable constant propagation so that methods referenced from ILLink.Substitutions.xml don't get inlined
       with a wrong value at library build time and the substitution can still be selected at publish time.
@@ -91,6 +90,7 @@
     <Compile Include="System\Runtime\CompilerServices\CallSite.cs" />
     <Compile Include="System\Runtime\CompilerServices\CallSiteBinder.cs" />
     <Compile Include="System\Runtime\CompilerServices\CallSiteOps.cs" />
+    <Compile Include="System\Runtime\CompilerServices\CallSiteOpsReflectionCache.cs" />
     <Compile Include="System\Runtime\CompilerServices\CallSiteHelpers.cs" />
     <Compile Include="System\Runtime\CompilerServices\DynamicAttribute.cs" />
     <Compile Include="System\Runtime\CompilerServices\DebugInfoGenerator.cs" />

src/libraries/System.Linq.Expressions/src/System/Dynamic/DynamicObject.cs

@@ -611,8 +611,7 @@ private DynamicMetaObject BuildCallMethodWithResult<TBinder>(MethodInfo method,
                                     Expression.Call(
                                         String_Format_String_ObjectArray,
                                         Expression.Constant(convertFailed),
-                                        Expression.NewArrayInit(
-                                            typeof(object),
+                                        Expression.NewObjectArrayInit(
                                             new TrueReadOnlyCollection<Expression>(
                                                 Expression.Condition(
                                                     Expression.Equal(resultMO.Expression, AstUtils.Null),
@@ -645,7 +644,7 @@ private DynamicMetaObject BuildCallMethodWithResult<TBinder>(MethodInfo method,
                     Expression.Block(
                         new TrueReadOnlyCollection<ParameterExpression>(result, callArgs),
                         new TrueReadOnlyCollection<Expression>(
-                            method != DynamicObject_TryBinaryOperation ? Expression.Assign(callArgs, Expression.NewArrayInit(typeof(object), callArgsValue)) : Expression.Assign(callArgs, callArgsValue[0]),
+                            method != DynamicObject_TryBinaryOperation ? Expression.Assign(callArgs, Expression.NewObjectArrayInit(callArgsValue)) : Expression.Assign(callArgs, callArgsValue[0]),
                             Expression.Condition(
                                 Expression.Call(
                                     GetLimitedSelf(),
@@ -705,7 +704,7 @@ private DynamicMetaObject CallMethodReturnLast<TBinder>(MethodInfo method, TBind
                     Expression.Block(
                         new TrueReadOnlyCollection<ParameterExpression>(result, callArgs),
                         new TrueReadOnlyCollection<Expression>(
-                            Expression.Assign(callArgs, Expression.NewArrayInit(typeof(object), callArgsValue)),
+                            Expression.Assign(callArgs, Expression.NewObjectArrayInit(callArgsValue)),
                             Expression.Condition(
                                 Expression.Call(
                                     GetLimitedSelf(),
@@ -768,7 +767,7 @@ private DynamicMetaObject CallMethodNoResult<TBinder>(MethodInfo method, TBinder
                     Expression.Block(
                         new TrueReadOnlyCollection<ParameterExpression>(callArgs),
                         new TrueReadOnlyCollection<Expression>(
-                            Expression.Assign(callArgs, Expression.NewArrayInit(typeof(object), callArgsValue)),
+                            Expression.Assign(callArgs, Expression.NewObjectArrayInit(callArgsValue)),
                             Expression.Condition(
                                 Expression.Call(
                                     GetLimitedSelf(),

src/libraries/System.Linq.Expressions/src/System/Dynamic/Utils/CachedReflectionInfo.cs

@@ -21,10 +21,6 @@ internal static partial class CachedReflectionInfo
         public static MethodInfo CallSiteOps_SetNotMatched =>
             s_CallSiteOps_SetNotMatched ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.SetNotMatched))!;
 
-        private static MethodInfo? s_CallSiteOps_CreateMatchmaker;
-        public static MethodInfo CallSiteOps_CreateMatchmaker =>
-            s_CallSiteOps_CreateMatchmaker ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.CreateMatchmaker))!;
-
         private static MethodInfo? s_CallSiteOps_GetMatch;
         public static MethodInfo CallSiteOps_GetMatch =>
             s_CallSiteOps_GetMatch ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.GetMatch))!;
@@ -33,34 +29,6 @@ internal static partial class CachedReflectionInfo
         public static MethodInfo CallSiteOps_ClearMatch =>
             s_CallSiteOps_ClearMatch ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.ClearMatch))!;
 
-        private static MethodInfo? s_CallSiteOps_UpdateRules;
-        public static MethodInfo CallSiteOps_UpdateRules =>
-            s_CallSiteOps_UpdateRules ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.UpdateRules))!;
-
-        private static MethodInfo? s_CallSiteOps_GetRules;
-        public static MethodInfo CallSiteOps_GetRules =>
-            s_CallSiteOps_GetRules ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.GetRules))!;
-
-        private static MethodInfo? s_CallSiteOps_GetRuleCache;
-        public static MethodInfo CallSiteOps_GetRuleCache =>
-            s_CallSiteOps_GetRuleCache ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.GetRuleCache))!;
-
-        private static MethodInfo? s_CallSiteOps_GetCachedRules;
-        public static MethodInfo CallSiteOps_GetCachedRules =>
-            s_CallSiteOps_GetCachedRules ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.GetCachedRules))!;
-
-        private static MethodInfo? s_CallSiteOps_AddRule;
-        public static MethodInfo CallSiteOps_AddRule =>
-            s_CallSiteOps_AddRule ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.AddRule))!;
-
-        private static MethodInfo? s_CallSiteOps_MoveRule;
-        public static MethodInfo CallSiteOps_MoveRule =>
-            s_CallSiteOps_MoveRule ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.MoveRule))!;
-
-        private static MethodInfo? s_CallSiteOps_Bind;
-        public static MethodInfo CallSiteOps_Bind =>
-            s_CallSiteOps_Bind ??= typeof(CallSiteOps).GetMethod(nameof(CallSiteOps.Bind))!;
-
         private static MethodInfo? s_DynamicObject_TryGetMember;
         public static MethodInfo DynamicObject_TryGetMember =>
             s_DynamicObject_TryGetMember ??= typeof(DynamicObject).GetMethod(nameof(DynamicObject.TryGetMember))!;

src/libraries/System.Linq.Expressions/src/System/Dynamic/Utils/DelegateHelpers.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics.CodeAnalysis;
+using System.Linq.Expressions;
 using System.Reflection;
 using System.Reflection.Emit;
 using System.Runtime.CompilerServices;
@@ -55,7 +56,10 @@ internal static Delegate CreateObjectArrayDelegate(Type delegateType, Func<objec
         {
             if (CanEmitObjectArrayDelegate)
             {
+#pragma warning disable IL3050
+                // Suppress analyzer warnings since they don't currently support feature flags
                 return CreateObjectArrayDelegateRefEmit(delegateType, handler);
+#pragma warning restore IL3050
             }
             else
             {
@@ -100,8 +104,7 @@ public static TReturn FuncThunk2<T1, T2, TReturn>(Func<object?[], object> handle
             return (TReturn)handler(new object?[]{t1, t2});
         }
 
-        private static MethodInfo GetEmptyObjectArrayMethod() =>
-            typeof(Array).GetMethod(nameof(Array.Empty))!.MakeGenericMethod(typeof(object));
+        private static MethodInfo GetEmptyObjectArrayMethod() => ((Func<object[]>)Array.Empty<object>).GetMethodInfo();
 
         private static MethodInfo[] GetActionThunks()
         {
@@ -121,6 +124,7 @@ private static MethodInfo[] GetFuncThunks()
 
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2060:MakeGenericMethod",
             Justification = "The above ActionThunk and FuncThunk methods don't have trimming annotations.")]
+        [RequiresDynamicCode(Expression.GenericMethodRequiresDynamicCode)]
         private static MethodInfo? GetCSharpThunk(Type returnType, bool hasReturnValue, ParameterInfo[] parameters)
         {
             try
@@ -193,6 +197,7 @@ private static MethodInfo[] GetFuncThunks()
         //      param0 = (T0)args[0];   // only generated for each byref argument
         // }
         // return (TRet)ret;
+        [RequiresDynamicCode("Ref emit requires dynamic code.")]
         private static Delegate CreateObjectArrayDelegateRefEmit(Type delegateType, Func<object?[], object?> handler)
         {
             if (!s_thunks.TryGetValue(delegateType, out MethodInfo? thunkMethod))