akashchamp · Sep 24, 2026
@@ -67,6 +67,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HelloWorldAttributes", "hel
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KeyedServices", "dependency-injection\keyed\KeyedServices.csproj", "{30674755-09B2-41DC-8AAD-31AC4541E562}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "trimming", "trimming", "{05379A49-3DC7-FF82-2FE9-08CAF8CE680F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TrimmingSample", "trimming\TrimmingSample.csproj", "{8A57091B-7A35-4EA6-A863-AC2076188700}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -389,6 +393,18 @@ Global
 		{30674755-09B2-41DC-8AAD-31AC4541E562}.Release|x64.Build.0 = Release|Any CPU
 		{30674755-09B2-41DC-8AAD-31AC4541E562}.Release|x86.ActiveCfg = Release|Any CPU
 		{30674755-09B2-41DC-8AAD-31AC4541E562}.Release|x86.Build.0 = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|x64.Build.0 = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Debug|x86.Build.0 = Debug|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|x64.ActiveCfg = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|x64.Build.0 = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|x86.ActiveCfg = Release|Any CPU
+		{8A57091B-7A35-4EA6-A863-AC2076188700}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -409,6 +425,7 @@ Global
 		{A4F3D30A-4124-49B0-A888-F81CE682F491} = {13EC390A-3D6F-4A7E-A02C-D3CBA197FA40}
 		{B38FF032-9AFB-481F-A432-DFA7A5100C3A} = {13EC390A-3D6F-4A7E-A02C-D3CBA197FA40}
 		{30674755-09B2-41DC-8AAD-31AC4541E562} = {E03982B3-80F2-4D55-9501-378EACE93E5B}
+		{8A57091B-7A35-4EA6-A863-AC2076188700} = {05379A49-3DC7-FF82-2FE9-08CAF8CE680F}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {43B81702-C1EF-43B6-B57D-C630AD1F555D}

@@ -0,0 +1,25 @@
+// Copyright (c) Nate McMaster.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using McMaster.Extensions.CommandLineUtils;
+
+// Reproduces https://github.com/natemcmaster/CommandLineUtils/issues/539:
+// a trimmed, self-contained, single-file publish using CommandLineApplication.Execute<TApp>
+// with an attribute-based command model. Before the fix, a trimmed publish either warned
+// during publish (when EnableTrimAnalyzer is set) or threw at run time with
+// "No method named 'OnExecute' or 'OnExecuteAsync' could be found." /
+// "Could not find any public constructors of type 'MyCommand'."
+return CommandLineApplication.Execute<MyCommand>(args);
+
+internal class MyCommand
+{
+    [Option(Description = "The subject to greet")]
+    public string Subject { get; } = "world";
+
+    private int OnExecute()
+    {
+        Console.WriteLine($"Hello, {Subject}!");
+        return 0;
+    }
+}
@@ -0,0 +1,29 @@
+Trimming sample for McMaster.Extensions.CommandLineUtils
+==========================================================
+
+Demonstrates publishing a trimmed, self-contained, single-file app that uses
+`McMaster.Extensions.CommandLineUtils.CommandLineApplication.Execute<TApp>`.
+
+See [issue #539](https://github.com/natemcmaster/CommandLineUtils/issues/539).
+
+Instructions
+------------
+
+From the repository root, publish the sample for your runtime (Linux x64 example):
+
+```bash
+dotnet publish docs/samples/trimming/TrimmingSample.csproj -c Release -r linux-x64
+```
+
+Because the project sets `EnableTrimAnalyzer` and `TreatWarningsAsErrors`, the publish
+itself fails if the trimmer finds any unannotated reflection reachable from this sample -
+so this project doubles as a regression check, not just a demo.
+
+Run the produced binary (path is printed at the end of the publish, under
+`docs/samples/trimming/bin/Release/net8.0/<rid>/publish`):
+
+```bash
+./docs/samples/trimming/bin/Release/net8.0/linux-x64/publish/TrimmingSample --subject Trimming
+```
+
+Expected output: `Hello, Trimming!`
@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <InvariantGlobalization>true</InvariantGlobalization>
+    <IsPackable>false</IsPackable>
+
+    <!-- Publish self-contained, trimmed, single-file to exercise the library under trimming,
+         matching the repro in https://github.com/natemcmaster/CommandLineUtils/issues/539. -->
+    <PublishSingleFile>true</PublishSingleFile>
+    <SelfContained>true</SelfContained>
+    <PublishTrimmed>true</PublishTrimmed>
+
+    <!-- Fail the build if the trimmer finds a problem, so this sample doubles as a regression
+         check for #539 instead of only a manual demo. -->
+    <EnableTrimAnalyzer>true</EnableTrimAnalyzer>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\CommandLineUtils\McMaster.Extensions.CommandLineUtils.csproj" />
+  </ItemGroup>
+
+</Project>
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 
 namespace McMaster.Extensions.CommandLineUtils.Abstractions
 {
@@ -14,6 +15,7 @@ public interface IModelAccessor
         /// Gets the type of the model.
         /// </summary>
         /// <returns>The type.</returns>
+        [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
         Type GetModelType();
 
         /// <summary>

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
@@ -48,17 +49,29 @@ internal ValueParserProvider()
         /// </remarks>
         public CultureInfo ParseCulture { get; set; } = CultureInfo.CurrentCulture;
 
-        private static readonly MethodInfo s_getParserGeneric
-            = typeof(ValueParserProvider)
+        private static readonly MethodInfo s_getParserGeneric;
+
+        [UnconditionalSuppressMessage("Trimming", "IL2111",
+            Justification = "GetParser<T>() is looked up here purely so GetParser(Type) can re-dispatch to it " +
+                "generically below; the annotations on its T parameter are honored because the Type passed " +
+                "into GetParser(Type) is itself annotated with DynamicallyAccessedMemberTypes.All.")]
+        static ValueParserProvider()
+        {
+            s_getParserGeneric = typeof(ValueParserProvider)
                 .GetMethods(BindingFlags.Instance | BindingFlags.Public)
                 .Single(m => m.Name == nameof(GetParser) && m.IsGenericMethod);
+        }
 
         /// <summary>
         /// Returns a parser registered for the given type.
         /// </summary>
         /// <param name="type"></param>
         /// <returns></returns>
-        public IValueParser GetParser(Type type)
+        [UnconditionalSuppressMessage("Trimming", "IL2060",
+            Justification = "type is annotated with DynamicallyAccessedMemberTypes.All, so the members " +
+                "GetParser<T>() needs from it are preserved even though MakeGenericMethod's own use of type " +
+                "cannot be statically verified by the trimmer.")]
+        public IValueParser GetParser([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] Type type)
         {
             var method = s_getParserGeneric.MakeGenericMethod(type);
 #pragma warning disable CS8600 // Converting null literal or possible null value to non-nullable type.
@@ -76,7 +89,7 @@ public IValueParser GetParser(Type type)
         /// </remarks>
         /// <typeparam name="T"></typeparam>
         /// <returns></returns>
-        public IValueParser<T>? GetParser<T>()
+        public IValueParser<T>? GetParser<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] T>()
         {
             var parser = GetParserImpl<T>();
             return parser switch
@@ -87,7 +100,17 @@ public IValueParser GetParser(Type type)
             };
         }
 
-        internal IValueParser? GetParserImpl<T>()
+        [UnconditionalSuppressMessage("Trimming", "IL2026",
+            Justification = "TryGetParser<T> (TypeDescriptor-based) is only reached when T is not one of the " +
+                "stock value-parser types, an enum, or Nullable<T> thereof. T is annotated with " +
+                "DynamicallyAccessedMemberTypes.All so its members survive trimming when this fallback runs.")]
+        [UnconditionalSuppressMessage("Trimming", "IL2072",
+            Justification = "type is typeof(T) where T is annotated with DynamicallyAccessedMemberTypes.All, so " +
+                "the array/wrapped element types reached through Type.GetElementType() and ReflectionHelper's " +
+                "Is*Type helpers are reachable through T even though those helpers do not themselves carry a " +
+                "matching annotation on their return/out value.")]
+        [UnconditionalSuppressMessage("Trimming", "IL2067", Justification = "See the IL2072 suppression above.")]
+        internal IValueParser? GetParserImpl<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] T>()
         {
             var type = typeof(T);
             if (_parsers.TryGetValue(type, out var parser))

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using McMaster.Extensions.CommandLineUtils.Abstractions;
 
@@ -95,6 +96,11 @@ internal CommandOption Configure(CommandLineApplication app, PropertyInfo prop)
             return option;
         }
 
+        [UnconditionalSuppressMessage("Trimming", "IL2072",
+            Justification = "prop.PropertyType is not itself annotated (PropertyInfo.PropertyType has no " +
+                "DynamicallyAccessedMembers support), but prop's declaring model type flows from " +
+                "CommandLineApplication.Execute<TApp>'s DynamicallyAccessedMemberTypes.All-annotated TApp, so " +
+                "prop's own type is preserved by trimming.")]
         private CommandOptionType GetOptionType(PropertyInfo prop, ValueParserProvider valueParsers)
         {
             CommandOptionType optionType;

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace McMaster.Extensions.CommandLineUtils
@@ -39,7 +40,7 @@ public VersionOptionFromMemberAttribute(string template)
         /// </summary>
         public new string Template { get; set; }
 
-        internal CommandOption Configure(CommandLineApplication app, Type type, Func<object> targetInstanceFactory)
+        internal CommandOption Configure(CommandLineApplication app, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] Type type, Func<object> targetInstanceFactory)
         {
             Func<string>? shortFormGetter = null;
             Func<string>? longFormGetter = null;

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -29,7 +30,7 @@ partial class CommandLineApplication
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static int Execute<TApp>(CommandLineContext context)
+        public static int Execute<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(CommandLineContext context)
             where TApp : class
             => ExecuteAsync<TApp>(context).GetAwaiter().GetResult();
 
@@ -47,7 +48,7 @@ public static int Execute<TApp>(CommandLineContext context)
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static async Task<int> ExecuteAsync<TApp>(CommandLineContext context, CancellationToken cancellationToken = default)
+        public static async Task<int> ExecuteAsync<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(CommandLineContext context, CancellationToken cancellationToken = default)
 #pragma warning restore RS0026 // Do not add multiple public overloads with optional parameters
             where TApp : class
         {
@@ -109,7 +110,7 @@ public static async Task<int> ExecuteAsync<TApp>(CommandLineContext context, Can
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static int Execute<TApp>(params string[] args)
+        public static int Execute<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(params string[] args)
             where TApp : class
             => Execute<TApp>(PhysicalConsole.Singleton, args);
 
@@ -126,7 +127,7 @@ public static int Execute<TApp>(params string[] args)
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static int Execute<TApp>(IConsole console, params string[] args)
+        public static int Execute<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(IConsole console, params string[] args)
             where TApp : class
         {
             args ??= Array.Empty<string>();
@@ -146,7 +147,7 @@ public static int Execute<TApp>(IConsole console, params string[] args)
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static Task<int> ExecuteAsync<TApp>(params string[] args)
+        public static Task<int> ExecuteAsync<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(params string[] args)
         where TApp : class
             => ExecuteAsync<TApp>(PhysicalConsole.Singleton, args);
 
@@ -164,7 +165,7 @@ public static Task<int> ExecuteAsync<TApp>(params string[] args)
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static Task<int> ExecuteAsync<TApp>(string[] args, CancellationToken cancellationToken = default)
+        public static Task<int> ExecuteAsync<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(string[] args, CancellationToken cancellationToken = default)
 #pragma warning restore RS0026 // Do not add multiple public overloads with optional parameters
         where TApp : class
         {
@@ -186,7 +187,7 @@ public static Task<int> ExecuteAsync<TApp>(string[] args, CancellationToken canc
         /// <typeparam name="TApp">A type that should be bound to the arguments.</typeparam>
         /// <exception cref="InvalidOperationException">Thrown when attributes are incorrectly configured.</exception>
         /// <returns>The process exit code</returns>
-        public static Task<int> ExecuteAsync<TApp>(IConsole console, params string[] args)
+        public static Task<int> ExecuteAsync<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TApp>(IConsole console, params string[] args)
             where TApp : class
         {
             args ??= Array.Empty<string>();