Fix unit test

README.md

@@ -9,7 +9,7 @@ Simply add a `PackageReference` to the [ReferenceTrimmer](https://www.nuget.org/
 
 The package contains build logic to emit warnings when unused dependencies are detected.
 
-Note: to get better effects, enable [`IDE0005`](https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/ide0005) unnecessary code rule. See also the note for why IDE0005 code analysis rule requires `<GenerateDocumentationFile>` property to be enabled.
+Note: to get better effects, enable [`IDE0005`](https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/ide0005) unnecessary code rule. See also the note for why IDE0005 code analysis rule requires `<GenerateDocumentationFile>` property to be enabled. Documentation generation is also required for accuracy of used references detection (based on https://github.com/dotnet/roslyn/issues/66188).
 
 ## Configuration
 `$(EnableReferenceTrimmer)` - Controls whether the build logic should run for a given project. Defaults to `true`.

analyzer/AnalyzerReleases.Shipped.md

@@ -7,4 +7,4 @@
 
 Rule ID | Category | Severity | Notes
 --------|----------|----------|--------------------
-RT0001  | References |  Warning | Unused references should be removed
+DOC001  | Documentation |  Warning | See https://github.com/dotnet/roslyn/issues/66188

analyzer/UsedAssemblyReferencesDumper.cs

@@ -7,8 +7,9 @@ namespace ReferenceTrimmer
     [DiagnosticAnalyzer(LanguageNames.CSharp, LanguageNames.VisualBasic, LanguageNames.FSharp)]
     public class UsedAssemblyReferencesDumper : DiagnosticAnalyzer
     {
-        internal static readonly string Title = "Unused references should be removed";
-        internal static DiagnosticDescriptor Rule = new DiagnosticDescriptor("RT0001", Title, "'{0}'", "References", DiagnosticSeverity.Warning, true, customTags: WellKnownDiagnosticTags.Unnecessary);
+        private static readonly string Title = "Enable documentation generation for accuracy of used references detection";
+        private static readonly string Message = "Enable /doc parameter or in MSBuild set <GenerateDocumentationFile>true</GenerateDocumentationFile> for accuracy of used references detection";
+        private static DiagnosticDescriptor Rule = new DiagnosticDescriptor("DOC001", Title, Message, "Documentation", DiagnosticSeverity.Warning, true);
 
         /// <summary>
         /// The supported diagnosticts.
@@ -25,6 +26,13 @@ public override void Initialize(AnalysisContext context)
         private static void DumpUsedReferences(CompilationAnalysisContext context)
         {
             Compilation compilation = context.Compilation;
+            if (compilation.SyntaxTrees.FirstOrDefault()?.Options.DocumentationMode == DocumentationMode.None)
+            {
+                string nameOrPath = compilation.Options.ModuleName;
+                Location location = Location.None;
+                context.ReportDiagnostic(Diagnostic.Create(Rule, location, nameOrPath));
+            }
+
             if (compilation.Options.Errors.IsEmpty)
             {
                 IEnumerable<MetadataReference> usedReferences = compilation.GetUsedAssemblyReferences();

test/E2ETests.cs

@@ -28,6 +28,9 @@ public static void ClassInitialize(TestContext testContext)
             $@"<Project>
   <PropertyGroup>
     <ReferenceTrimmerTaskAssembly>{testOutputDir}\ReferenceTrimmer\ReferenceTrimmer.dll</ReferenceTrimmerTaskAssembly>
+    <!-- Per https://github.com/dotnet/roslyn/issues/66188 /doc param is required for accurate results -->
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <NoWarn>$(NoWarn);1591</NoWarn>
   </PropertyGroup>
   <ItemGroup>
     <Analyzer Include=""{testOutputDir}\ReferenceTrimmer\ReferenceTrimmerAnalyzer.dll""/>
@@ -116,6 +119,17 @@ public void UnusedPackageReference()
             });
     }
 
+    [TestMethod]
+    public void UnusedPackageReferenceDocDisabled()
+    {
+        RunMSBuild(
+            projectFile: @"Library\Library.csproj",
+            expectedWarnings: new[]
+            {
+                @"Enable /doc parameter or in MSBuild set <GenerateDocumentationFile>true</GenerateDocumentationFile> for accuracy of used references detection",
+            });
+    }
+
     [TestMethod]
     public void MissingReferenceSourceTarget()
     {

test/TestData/UnusedPackageReferenceDocDisabled/Library/Library.cs

@@ -0,0 +1,7 @@
+namespace Library
+{
+    public static class Foo
+    {
+        public static string Bar() => "Baz";
+    }
+}

test/TestData/UnusedPackageReferenceDocDisabled/Library/Library.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net472</TargetFramework>
+    <!-- Assert the analyzer reports diagnostic -->
+    <GenerateDocumentationFile>false</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
+  </ItemGroup>
+
+</Project>