Add polyfills for .NET 9 attributes.

.github/CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 Thank you for your interest in contributing to **PolySharp**! Below you'll find some info on how to get started with the project.
 
-> **NOTE:** it is highly recommended to carfully read the [README](/README.md) first to get a general understanding of the library.
+> **NOTE:** it is highly recommended to carefully read the [README](/README.md) first to get a general understanding of the library.
 
 ## 🙋 Questions, bug reports, feature proposals
 

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <LangVersion>12.0</LangVersion>
+    <LangVersion>13</LangVersion>
     <Nullable>enable</Nullable>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
 

README.md

@@ -52,6 +52,8 @@ Here's an example of some of the new features that **PolySharp** can enable down
 - `[RequiresLocation]` (needed to enable [ref readonly parameters](https://github.com/dotnet/csharplang/issues/6010))
 - `[CollectionBuilder]` (needed for [collection expressions](https://github.com/dotnet/csharplang/issues/5354))
 - `[Experimental]` (needed for [experimental features](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-12.0/experimental-attribute))
+- `[OverloadResolutionPriority]` (needed for [overload resolution priority](https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-13#overload-resolution-priority))
+- `[ParamsCollection]` (needed for [params collection](https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-13#params-collections))
 
 To leverage them, make sure to bump your C# language version. You can do this by setting the `<LangVersion>` MSBuild property in your project. For instance, by adding `<LangVersion>12.0</LangVersion>` (or your desired C# version) to the first `<PropertyGroup>` of your .csproj file. For more info on this, [see here](https://sergiopedri.medium.com/enabling-and-using-c-9-features-on-older-and-unsupported-runtimes-ce384d8debb), but remember that you don't need to manually copy polyfills anymore: simply adding a reference to **PolySharp** will do this for you automatically.
 
@@ -64,7 +66,7 @@ It also includes the following optional runtime-supported polyfills:
   - `[UnconditionalSuppressMessage]`
   - `[RequiresAssemblyFiles]`
 - `[StackTraceHidden]` (see [here](https://makolyte.com/csharp-exclude-exception-throw-helper-methods-from-the-stack-trace/))
-- `[UnmanagedCallersOnly]` (see [docs](https://learn.microsoft.com/dotnet/api/system.runtime.interopservices.unmanagedcallersonlyattribute)))
+- `[UnmanagedCallersOnly]` (see [docs](https://learn.microsoft.com/dotnet/api/system.runtime.interopservices.unmanagedcallersonlyattribute))
 - Platform support annotation attributes (see [docs](https://learn.microsoft.com/dotnet/standard/analyzers/platform-compat-analyzer)):
   - `[ObsoletedOSPlatform]`
   - `[SupportedOSPlatform]`
@@ -76,6 +78,11 @@ It also includes the following optional runtime-supported polyfills:
 - `[DisableRuntimeMarshalling]` (see [here](https://learn.microsoft.com/dotnet/standard/native-interop/disabled-marshalling))
 - `[UnsafeAccessor]` (see [here](https://github.com/dotnet/runtime/issues/81741))
 - `[InlineArray]` (see [here](https://learn.microsoft.com/dotnet/csharp/language-reference/proposals/csharp-12.0/inline-arrays))
+- `[DisableUserUnhandledExceptions]` (see [here](https://github.com/dotnet/runtime/issues/103105))
+- Attribute model for feature switches with trimming support (see [docs](https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/runtime#attribute-model-for-feature-switches-with-trimming-support)):
+  - `[FeatureGuard]`
+  - `[FeatureSwitchDefinition]`
+- `[WasmImportLinkage]` (see [here](https://github.com/dotnet/runtime/pull/93823))
 
 # Options ⚙️
 

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "8.0.100",
+    "version": "9.0.100-rc.1.24452.12",
     "rollForward": "latestFeature",
     "allowPrerelease": false
   }

src/PolySharp.SourceGenerators/EmbeddedResources/RuntimeSupported/System.Diagnostics.CodeAnalysis.FeatureGuardAttribute.cs

@@ -0,0 +1,41 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Diagnostics.CodeAnalysis
+{
+    /// <summary>
+    /// Indicates that the specified public static boolean get-only property
+    /// guards access to the specified feature.
+    /// </summary>
+    /// <remarks>
+    /// Analyzers can use this to prevent warnings on calls to code that is
+    /// annotated as requiring that feature, when the callsite is guarded by a
+    /// call to the property.
+    /// </remarks>
+    [global::System.AttributeUsage(global::System.AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    [global::System.Diagnostics.Conditional("MULTI_TARGETING_SUPPORT_ATTRIBUTES")]
+    internal sealed class FeatureGuardAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FeatureGuardAttribute"/> class
+        /// with the specified feature type.
+        /// </summary>
+        /// <param name="featureType">
+        /// The type that represents the feature guarded by the property.
+        /// </param>
+        public FeatureGuardAttribute(Type featureType)
+        {
+            FeatureType = featureType;
+        }
+
+        /// <summary>
+        /// The type that represents the feature guarded by the property.
+        /// </summary>
+        public Type FeatureType { get; }
+    }
+}

src/PolySharp.SourceGenerators/EmbeddedResources/RuntimeSupported/System.Diagnostics.CodeAnalysis.FeatureSwitchDefinitionAttribute.cs

@@ -0,0 +1,40 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Diagnostics.CodeAnalysis
+{
+    /// <summary>
+    /// Indicates that the specified public static boolean get-only property
+    /// corresponds to the feature switch specified by name.
+    /// </summary>
+    /// <remarks>
+    /// IL rewriters and compilers can use this to substitute the return value
+    /// of the specified property with the value of the feature switch.
+    /// </remarks>
+    [global::System.AttributeUsage(global::System.AttributeTargets.Property, Inherited = false)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    [global::System.Diagnostics.Conditional("MULTI_TARGETING_SUPPORT_ATTRIBUTES")]
+    internal sealed class FeatureSwitchDefinitionAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FeatureSwitchDefinitionAttribute"/> class
+        /// with the specified feature switch name.
+        /// </summary>
+        /// <param name="switchName">
+        /// The name of the feature switch that provides the value for the specified property.
+        /// </param>
+        public FeatureSwitchDefinitionAttribute(string switchName)
+        {
+            SwitchName = switchName;
+        }
+
+        /// <summary>
+        /// The name of the feature switch that provides the value for the specified property.
+        /// </summary>
+        public string SwitchName { get; }
+    }
+}

src/PolySharp.SourceGenerators/EmbeddedResources/RuntimeSupported/System.Diagnostics.DebuggerDisableUserUnhandledExceptionsAttribute.cs

@@ -0,0 +1,21 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Diagnostics
+{
+    /// <summary>
+    /// If a .NET Debugger is attached which supports the Debugger.BreakForUserUnhandledException(Exception) API,
+    /// this attribute will prevent the debugger from breaking on user-unhandled exceptions when the
+    /// exception is caught by a method with this attribute, unless BreakForUserUnhandledException is called.
+    /// </summary>
+    [global::System.AttributeUsage(global::System.AttributeTargets.Method)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    [global::System.Diagnostics.Conditional("MULTI_TARGETING_SUPPORT_ATTRIBUTES")]
+    internal sealed class DebuggerDisableUserUnhandledExceptionsAttribute : Attribute
+    {
+    }
+}

src/PolySharp.SourceGenerators/EmbeddedResources/RuntimeSupported/System.Runtime.InteropServices.WasmImportLinkageAttribute.cs

@@ -0,0 +1,26 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.InteropServices
+{
+    /// <summary>
+    /// Specifies that the P/Invoke marked with this attribute should be linked in as a WASM import.
+    /// </summary>
+    /// <remarks>
+    /// See https://webassembly.github.io/spec/core/syntax/modules.html#imports.
+    /// </remarks>
+    [global::System.AttributeUsage(global::System.AttributeTargets.Method, Inherited = false)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    [global::System.Diagnostics.Conditional("MULTI_TARGETING_SUPPORT_ATTRIBUTES")]
+    internal sealed class WasmImportLinkageAttribute : Attribute
+    {
+        /// <summary>
+        /// Instance constructor.
+        /// </summary>
+        public WasmImportLinkageAttribute() { }
+    }
+}

src/PolySharp.SourceGenerators/EmbeddedResources/System.Runtime.CompilerServices.OverloadResolutionPriorityAttribute.cs

@@ -0,0 +1,36 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Specifies the priority of a member in overload resolution. When unspecified, the default priority is 0.
+    /// </summary>
+    [global::System.AttributeUsage(
+        global::System.AttributeTargets.Method |
+        global::System.AttributeTargets.Constructor |
+        global::System.AttributeTargets.Property,
+        AllowMultiple = false,
+        Inherited = false)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    internal sealed class OverloadResolutionPriorityAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OverloadResolutionPriorityAttribute"/> class.
+        /// </summary>
+        /// <param name="priority">The priority of the attributed member. Higher numbers are prioritized, lower numbers are deprioritized. 0 is the default if no attribute is present.</param>
+        public OverloadResolutionPriorityAttribute(int priority)
+        {
+            Priority = priority;
+        }
+
+        /// <summary>
+        /// The priority of the member.
+        /// </summary>
+        public int Priority { get; }
+    }
+}

src/PolySharp.SourceGenerators/EmbeddedResources/System.Runtime.CompilerServices.ParamCollectionAttribute.cs

@@ -0,0 +1,18 @@
+// <auto-generated/>
+#pragma warning disable
+#nullable enable annotations
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Indicates that a method will allow a variable number of arguments in its invocation.
+    /// </summary>
+    [global::System.AttributeUsage(global::System.AttributeTargets.Parameter, Inherited = true, AllowMultiple = false)]
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    internal sealed class ParamCollectionAttribute : Attribute
+    {
+    }
+}

tests/PolySharp.Tests/LanguageFeatures.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.Versioning;
@@ -121,6 +122,8 @@ internal class TestClassWithRequiredMembers
     public TestClassWithRequiredMembers()
     {
         Name = "";
+        // Dummy piece of code to not trigger IDE0290 (use primary constructor)
+        Debug.Assert(Name is not null);
     }
 
     // CompilerFeatureRequiredAttribute, RequiredMemberAttribute
@@ -160,11 +163,17 @@ public static ReadOnlySpan<int> TestRange(ReadOnlySpan<int> numbers)
 [CollectionBuilder(typeof(CollectionClass), nameof(Create))]
 internal class CollectionClass : IEnumerable<int>
 {
-    public CollectionClass Test()
+    public static CollectionClass Test()
     {
+        Test2(1, 2, 3);
         return [1, 2, 3];
     }
 
+    public static void Test2(params CollectionClass collection)
+    {
+
+    }
+
     public static CollectionClass Create(ReadOnlySpan<int> values)
     {
         return new();
@@ -258,4 +267,22 @@ public void Start<TStateMachine>(ref TStateMachine stateMachine)
     }
 }
 
-#endif
+#endif
+
+internal static class OverloadResolutionPriorityTests
+{
+    public static void Test()
+    {
+        TestOverload(1);
+    }
+
+    [Obsolete("Do not use", error: true)]
+    [OverloadResolutionPriority(-1)]
+    public static void TestOverload(int x)
+    {
+    }
+
+    public static void TestOverload(int x, int y = 0)
+    {
+    }
+}

tests/PolySharp.Tests/PolySharp.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net48;netstandard2.0;netstandard2.1;net6.0;net7.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net48;netstandard2.0;netstandard2.1;net6.0;net7.0;net8.0;net9.0</TargetFrameworks>
     <PolySharpIncludeRuntimeSupportedAttributes>true</PolySharpIncludeRuntimeSupportedAttributes>
   </PropertyGroup>