Add set up for validations generator

eng/testing/linker/SupportFiles/Directory.Build.targets

@@ -76,7 +76,7 @@
     <ProjectReference Include="$(RepoRoot)src\SignalR\clients\csharp\Client\src\Microsoft.AspNetCore.SignalR.Client.csproj" />
     <ProjectReference Include="$(RepoRoot)src\SignalR\server\SignalR\src\Microsoft.AspNetCore.SignalR.csproj" />
     <ProjectReference Include="$(RepoRoot)src\OpenApi\src\Microsoft.AspNetCore.OpenApi.csproj" />
-    <ProjectReference Include="$(RepoRoot)src\Http\Http.Extensions\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="$(RepoRoot)src\Http\Http.Extensions\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
 </Project>

src/Framework/App.Ref/src/Microsoft.AspNetCore.App.Ref.sfxproj

@@ -72,7 +72,7 @@
       OutputItemType="AspNetCoreAnalyzer"
       ReferenceOutputAssembly="false" />
 
-    <ProjectReference Include="$(RepoRoot)src\Http\Http.Extensions\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj"
+    <ProjectReference Include="$(RepoRoot)src\Http\Http.Extensions\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj"
       Private="false"
       OutputItemType="AspNetCoreAnalyzer"
       ReferenceOutputAssembly="false" />

src/Http/Http.Extensions/gen/Microsoft.AspNetCore.Http.ValidationsGenerator/Microsoft.AspNetCore.Http.ValidationsGenerator.csproj

@@ -0,0 +1,33 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <EnforceExtendedAnalyzerRules>true</EnforceExtendedAnalyzerRules>
+    <IsPackable>false</IsPackable>
+    <IsAnalyzersProject>true</IsAnalyzersProject>
+    <AddPublicApiAnalyzers>false</AddPublicApiAnalyzers>
+    <Nullable>enable</Nullable>
+    <WarnOnNullable>true</WarnOnNullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="All" IsImplicitlyDefined="true" Version="$(MicrosoftCodeAnalysisVersion_LatestVS)" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="All" IsImplicitlyDefined="true" Version="$(MicrosoftCodeAnalysisVersion_LatestVS)" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.Http.Extensions.Tests" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="$(SharedSourceRoot)IsExternalInit.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)HashCode.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)RoslynUtils\BoundedCacheWithFactory.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)RoslynUtils\WellKnownTypeData.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)RoslynUtils\WellKnownTypes.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)RoslynUtils\CodeWriter.cs" LinkBase="Shared" />
+    <Compile Include="$(RepoRoot)\src\Http\Http.Extensions\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator\StaticRouteHandlerModel\InvocationOperationExtensions.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Diagnostics\AnalyzerDebug.cs" LinkBase="Shared" />
+  </ItemGroup>
+
+</Project>

src/Http/Http.Extensions/gen/Microsoft.AspNetCore.Http.ValidationsGenerator/ValidationsGenerator.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.CodeAnalysis;
+
+namespace Microsoft.AspNetCore.Http.ValidationsGenerator;
+
+public sealed partial class ValidationsGenerator : IIncrementalGenerator
+{
+    public void Initialize(IncrementalGeneratorInitializationContext context)
+    {
+        return;
+    }
+}

src/Http/Http.Extensions/test/Microsoft.AspNetCore.Http.Extensions.Tests.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
     <!-- This is needed to support codepaths that use NullabilityInfoContext. -->
-    <Features>$(Features.Replace('nullablePublicOnly', '')</Features>
+    <Features>$(Features.Replace('nullablePublicOnly', ''))</Features>
     <PreserveCompilationContext>true</PreserveCompilationContext>
   </PropertyGroup>
 
@@ -21,6 +21,8 @@
     <Reference Include="Microsoft.AspNetCore.TestHost" />
     <Reference Include="Microsoft.Extensions.DependencyInjection" />
     <Reference Include="Microsoft.Extensions.DependencyModel" />
+    <Reference Include="Verify.XUnit" />
+    <Reference Include="Verify.SourceGenerators" />
   </ItemGroup>
 
   <ItemGroup>
@@ -29,7 +31,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj" />
+    <ProjectReference Include="..\gen\Microsoft.AspNetCore.Http.RequestDelegateGenerator\Microsoft.AspNetCore.Http.RequestDelegateGenerator.csproj" />
+    <ProjectReference Include="..\gen\Microsoft.AspNetCore.Http.ValidationsGenerator\Microsoft.AspNetCore.Http.ValidationsGenerator.csproj" />
+
   </ItemGroup>
 
   <ItemGroup>
@@ -41,5 +45,6 @@
 
   <ItemGroup>
     <HelixContent Include="$(MSBuildProjectDirectory)\RequestDelegateGenerator\Baselines\**" />
+    <HelixContent Include="$(MSBuildProjectDirectory)\ValidationsGenerator\snapshots\**" />
   </ItemGroup>
 </Project>

src/Http/Http.Extensions/test/ValidationsGenerator/ValidationsGenerator.Parameters.cs

@@ -0,0 +1,44 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Http.ValidationsGenerator.Tests;
+
+public partial class ValidationsGeneratorTests : ValidationsGeneratorTestBase
+{
+    [Fact]
+    public async Task CanValidateParameters()
+    {
+        var source = """
+using System;
+using System.ComponentModel.DataAnnotations;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Routing;
+
+var builder = WebApplication.CreateBuilder();
+
+var app = builder.Build();
+
+app.MapGet("/params", (
+    [Range(10, 100)] int value1,
+    [Range(10, 100), Display(Name = "Valid identifier")] int value2,
+    [Required] string value3 = "some-value",
+    [CustomValidation(ErrorMessage = "Value must be an even number")] int value4 = 4,
+    [CustomValidation, Range(10, 100)] int value5 = 10) => "OK");
+
+app.Run();
+
+public class CustomValidationAttribute : ValidationAttribute
+{
+    public override bool IsValid(object? value) => value is int number && number % 2 == 0;
+}
+""";
+        await Verify(source, out var compilation);
+        VerifyEndpoint(compilation, "/params", async endpoint =>
+        {
+            var context = CreateHttpContext();
+            context.Request.QueryString = new QueryString("?value1=5&value2=5&value3=&value4=3&value5=5");
+            await endpoint.RequestDelegate(context);
+            Assert.Equal(StatusCodes.Status200OK, context.Response.StatusCode);
+        });
+    }
+}