Handle breaking changes

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -62,12 +62,14 @@ body:
           required: true
         - label: I have provided a descriptive title for this issue
           required: true
-        - label: I have made sure that that this bug is reproducible on the latest version of the package
+        - label: I have made sure that this bug is reproducible on the latest version of the package
           required: true
         - label: I have provided all the information needed to reproduce this bug as efficiently as possible
           required: true
         - label: I have sponsored this project
           required: false
+        - label: I have not read any of the above and just checked all the boxes to submit the issue
+          required: false
 
   - type: markdown
     attributes:

.github/dependabot.yml

@@ -0,0 +1,22 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: monthly
+    labels:
+      - enhancement
+    groups:
+      actions:
+        patterns:
+          - "*"
+  - package-ecosystem: nuget
+    directory: "/"
+    schedule:
+      interval: monthly
+    labels:
+      - enhancement
+    groups:
+      nuget:
+        patterns:
+          - "*"

.github/workflows/main.yml

@@ -13,16 +13,21 @@ on:
         required: false
         default: false
   push:
+    branches:
+      - master
+    tags:
+      - "*"
   pull_request:
+    branches:
+      - master
 
 jobs:
   main:
     uses: Tyrrrz/.github/.github/workflows/nuget.yml@master
     with:
-      dotnet-version: 8.0.x
+      deploy: ${{ inputs.deploy || github.ref_type == 'tag' }}
-      package-version: ${{ inputs.package-version }}
+      package-version: ${{ inputs.package-version || (github.ref_type == 'tag' && github.ref_name) || format('0.0.0-ci-{0}', github.sha) }}
-      # Deploy only on tags by default, unless deploy is explicitly requested
+      dotnet-version: 9.0.x
-      deploy-on-tags-only: ${{ !(github.event_name == 'workflow_dispatch' && inputs.deploy) }}
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
       NUGET_TOKEN: ${{ secrets.NUGET_TOKEN }}

Changelog.md

@@ -1,185 +0,0 @@
-# Changelog
-
-## v2.3.5 (16-Nov-2023)
-
-- Fixed an issue where calling `CliApplication.RunAsync(IReadOnlyList<string>)` could fail in very specific scenarios on Windows, if there were two global environment variables with the same name but different casing. (Thanks [@alirezanet](https://github.com/alirezanet))
-
-## v2.3.4 (18-May-2023)
-
-- Added an overload of `CliApplicationBuilder.UseTypeActivator(...)` that accepts a `Func<IReadOnlyList<Type>, IServiceProvider>` delegate. The first parameter in the delegate is the list of all command types registered in the application. You can use this overload to more easily add the commands to a DI container. See the readme for an [updated example](https://github.com/Tyrrrz/CliFx/tree/2.3.4#type-activation).
-
-## v2.3.3 (28-Apr-2023)
-
-- Fixed an issue where the analyzers failed to load in some projects, due to targeting a Roslyn version that was too high.
-
-## v2.3.2 (06-Apr-2023)
-
-- Added name-based ordering to subcommands when displayed in the help text. (Thanks [@CartBlanche](https://github.com/CartBlanche))
-
-## v2.3.1 (08-Dec-2022)
-
-- Added support for the `required` keyword introduced in C# 11. Command options bound to required properties are now marked as required by default (equivalent to setting `IsRequired = true` on the attribute). Also added analyzers that prevent marking an option or parameter non-required if it's bound to a required property.
-
-## v2.3 (12-Jul-2022)
-
-- Added console dimension properties `WindowWidth` and `WindowHeight` to `IConsole` interface and implementing classes.
-- Improved inline documentation for members of `IConsole` interface.
-
-## v2.2.6 (14-Jun-2022)
-
-- Added an overload of `CliApplicationBuilder.UseTypeActivator(...)` that accepts an instance of `IServiceProvider`. This slightly simplifies integration with many DI containers.
-- Fixed minor grammar mistakes in user-facing error messages.
-
-## v2.2.5 (10-May-2022)
-
-- Updated default value resolution for the application executable name. It will now resolve to `myapp.exe` instead of `dotnet myapp.dll` when the application is launched through the EXE apphost on Windows. On other platforms, or when running the application through the .NET CLI, the behavior will be the same as before.
-
-## v2.2.4 (22-Apr-2022)
-
-- Added more contextual information to analyzer diagnostics.
-- Fixed an issue where the analyzer incorrectly reported an error on converters that didn't directly match the target type but were compatible through known built-in conversions.
-- Fixed an issue where MSBuild produced a lot of analyzer-related warnings in certain circumstances.
-
-## v2.2.3 (17-Apr-2022)
-
-- Changed method signature of `IConsole.ReadKey()` to return `ConsoleKeyInfo` instead of `void`. The return type was originally defined as `void` by mistake. This change is source-backwards-compatible but may break on binary level if you were previously calling this method indirectly (i.e. through a library).
-- Added `FakeConsole.EnqueueKey(...)` to facilitate the testing of `IConsole.ReadKey()`. You can use this method to simulate key presses in your application.
-- Extended analyzers that verify the correctness of specified converters and validators. They now also ensure that the specified types are compatible with the type of the underlying property.
-- Improved diagnostics produced by analyzers. Where relevant, highlighted code is now limited to the property or type identifier, instead of the whole property or type declaration. Also extended the diagnostic messages with additional information.
-- Fixed an issue where throwing an exception inside a constructor of a command type resulted in an unrelated error message about the absence of a parameterless constructor.
-
-## v2.2.2 (30-Jan-2022)
-
-- Fixed an issue where `ConsoleWriter` and `ConsoleReader` were not properly thread-safe.
-- Fixed an issue where the analyzer failed to load under certain circumstances when running inside Visual Studio.
-
-## v2.2.1 (16-Jan-2022)
-
-- Fixed an issue which caused help text to not show default values for optional parameters. (Thanks [@AliReZa Sabouri](https://github.com/alirezanet))
-
-## v2.2 (11-Jan-2022)
-
-- Added support for optional parameters. A parameter can be marked as optional by setting `IsRequired = false` on the attribute. Only one parameter is allowed to be optional and such parameter must be the last in order. (Thanks [@AliReZa Sabouri](https://github.com/alirezanet))
-- Fixed an issue where parameters and options bound to properties implemented as default interface members were not working correctly. (Thanks [@AliReZa Sabouri](https://github.com/alirezanet))
-
-## v2.1 (04-Jan-2022)
-
-- Added `IConsole.Clear()` with corresponding implementations in `SystemConsole`, `FakeConsole`, and `FakeInMemoryConsole`. (Thanks [@Alex Rosenfeld](https://github.com/alexrosenfeld10))
-- Added `IConsole.ReadKey()` with corresponding implementations in `SystemConsole`, `FakeConsole`, and `FakeInMemoryConsole`. (Thanks [@Alex Rosenfeld](https://github.com/alexrosenfeld10))
-- Fixed an issue that caused parameters to appear out of order in the usage format section of the help text. (Thanks [@David Fallah](https://github.com/TAGC))
-
-## v2.0.6 (17-Jul-2021)
-
-- Fixed an issue where an exception thrown via reflection during parameter or option binding resulted in `Exception has been thrown by the target of an invocation` error instead of a more useful message. Such exceptions will now be unwrapped to provide better user experience.
-
-## v2.0.5 (09-Jul-2021)
-
-- Fixed an issue where calling `IConsole.Output.Encoding.EncodingName` and some other members threw an exception.
-- Added readme file to the package.
-
-## v2.0.4 (24-Apr-2021)
-
-- Fixed an issue where output and error streams in `SystemConsole` defaulted to UTF8 encoding with BOM when the application was running with UTF8 codepage. `ConsoleWriter` will now discard preamble from the specified encoding. This fix brings the behavior of `SystemConsole` in line with .NET's own `System.Console` which also discards preamble for output and error streams.
-- Fixed an issue where help text tried to show default values for parameters and options whose type does not override `ToString()` method.
-- Fixed an issue where help text didn't show default values for parameters and options whose type is an enumerable of nullable enums. (Thanks [@Robert Dailey](https://github.com/rcdailey))
-- Fixed an issue where specific parts of the help text weren't legible in some terminals due to low color resolution. Removed the usage of `ConsoleColor.DarkGray` in help text.
-
-## v2.0.3 (09-Apr-2021)
-
-- Improved help text by showing valid values for non-scalar enum parameters and options. (Thanks [@Robert Dailey](https://github.com/rcdailey))
-
-## v2.0.2 (31-Mar-2021)
-
-- Fixed an issue where having a transitive reference to CliFx sometimes resulted in `SystemConsoleShouldBeAvoidedAnalyzer` throwing `NullReferenceException` during build.
-- Fixed some documentation typos and inconsistencies.
-
-## v2.0.1 (24-Mar-2021)
-
-- Fixed an issue where some exceptions with async stack traces generated on .NET 3.1 or earlier were not parsed and formatted correctly.
-- Fixed an issue where help text applied slightly incorrect formatting when displaying choices for enum-based parameters and properties.
-
-## v2.0 (21-Mar-2021)
-
-> Note: this major release includes many breaking changes.
-> Please refer to the readme to find updated instructions and usage examples.
-
-- Renamed property `EnvironmentVariableName` to `EnvironmentVariable` on `CommandOption` attribute.
-- Removed most of schema validation checks that used to take place during application startup. Going forward, CliFx will be relying solely on its built-in set of Roslyn analyzers to catch common errors in command configuration.
-- Removed `ProgressTicker` utility. The recommended migration path is to use the [Spectre.Console](https://github.com/spectresystems/spectre.console) library which provides a wide array of console widgets and components. See [this wiki page](https://github.com/Tyrrrz/CliFx/wiki/Integrating-with-Spectre.Console) to learn how to integrate Spectre.Console with CliFx.
-- Removed `MemoryStreamWriter` utility as it's no longer used within CliFx.
-- Improved wording in all error messages.
-- Renamed some methods on `CliApplicationBuilder`:
-  - `UseTitle()` renamed to `SetTitle()`
-  - `UseExecutableName()` renamed to `SetExecutableName()`
-  - `UseVersionText()` renamed to `SetVersion()`
-  - `UseDescription()` renamed to `SetDescription()`
-- Changed the behavior of autogenerated help text:
-  - Changed the color scheme to a more neutral set of tones
-  - Assigned separate colors to parameters and options to make them visually stand out
-  - Usage section no longer lists usage formats of all descendant commands
-  - Command section now also lists available subcommands for each of the current command's subcommands
-- Changed the behavior of `[preview]` directive. Running the application with this directive will now also print all resolved environment variables, in addition to parsed command-line arguments.
-- Reworked `IArgumentValueConverter`/`ArgumentValueConverter` into `BindingConverter`. Method `ConvertFrom(...)` has been renamed to `Convert(...)`.
-- Reworked `ArgumentValueValidator` into `BindingValidator`. This class exposes an abstract `Validate(...)` method that returns a nullable `BindingValidationError`. This class also provides utility methods `Ok()` and `Error(...)` to help create corresponding validation results.
-- Changed the type of `IConsole.Output` and `IConsole.Error` from `StreamWriter` to `ConsoleWriter`. This type derives from `StreamWriter` and additionally exposes a `Console` property that refers to the console instance that owns the stream. This change enables you to author extension methods scoped specifically to console output and error streams.
-- Changed the type of `IConsole.Input` from `StreamReader` to `ConsoleReader`. This type derives from `StreamReader` and additionally exposes a `Console` property that refers to the console instance that owns the stream. This change enables you to author extension methods scoped specifically to the console input stream.
-- Changed methods `IConsole.WithForegroundColor(...)`, `IConsole.WithBackgroundColor(...)`, and `IConsole.WithColors(...)` to return `IDisposable`, replacing the delegate parameter they previously had. You can wrap the returned `IDisposable` in a using statement to ensure that the console colors get reset back to their original values once the execution reaches the end of the block.
-- Renamed `IConsole.GetCancellationToken()` to `IConsole.RegisterCancellationHandler()`.
-- Reworked `VirtualConsole` into `FakeConsole`. This class no longer takes `CancellationToken` as a constructor parameter, but instead encapsulates its own instance of `CancellationTokenSource` that can be triggered using the provided `RequestCancellation()` method.
-- Removed `VirtualConsole.CreateBuffered()` and replaced it with the `FakeInMemoryConsole` class. This class derives from `FakeConsole` and uses in-memory standard input, output, and error streams. It also provides methods to easily read the data written to the streams.
-- Moved some types to different namespaces:
-  - `IConsole`/`FakeConsole`/`FakeInMemoryConsole` moved from `CliFx` to `CliFx.Infrastructure`
-  - `ITypeActivator`/`DefaultTypeActivator`/`DelegateTypeActivator` moved from `CliFx` to `CliFx.Infrastructure`
-  - `BindingValidator`/`BindingConverter` moved from `CliFx` to `CliFx.Extensibility`
-
-## v1.6 (06-Dec-2020)
-
-- Added support for custom value validators. You can now create a type that inherits from `CliFx.ArgumentValueValidator<T>` to implement reusable validation logic for command arguments. To use a validator, include it in the `Validators` property on the `CommandOption` or `CommandParameter` attribute. (Thanks [@Oleksandr Shustov](https://github.com/AlexandrShustov))
-- Added `CliFx.ArgumentValueConverter<T>` class that you can inherit from to implement custom value converters. `CliFx.IArgumentValueConverter` interface is still available, but it is recommended to inherit from the generic class instead, due to the type safety it provides. The interface may become internal or get removed in one of the future major versions.
-- Updated requirements for option names and short names: short names now must be letter characters (lowercase or uppercase), while names must now start with a letter character. This means option names can no longer start with a digit or a special character. This change makes it possible to pass negative number values without the need to quote them, i.e. `--my-number -5`.
-
-## v1.5 (23-Oct-2020)
-
-- Added pretty-printing for unhandled exceptions thrown from within the application. This makes the errors easier to parse visually and should help in troubleshooting. This change does not affect `CommandException`, as it already has special treatment. (Thanks [@Mårten Åsberg](https://github.com/89netraM))
-- Added support for custom value converters. You can now create a type that implements `CliFx.IArgumentValueConverter` and specify it as a converter for your parameters or options via the `Converter` named property. This should enable conversion between raw argument values and custom types which are not string-initializable. (Thanks [@Oleksandr Shustov](https://github.com/AlexandrShustov))
-- Improved help text so that it also shows minimal usage examples for child and descendant commands, besides the actual command it was requested on. This should improve user experience for applications with many nested commands. (Thanks [@Nikiforov Alexey](https://github.com/NikiforovAll))
-
-## v1.4 (20-Aug-2020)
-
-- Added `VirtualConsole.CreateBuffered()` method to simplify test setup when using in-memory backing stores for output and error streams. Please refer to the readme for updated recommendations on how to test applications built with CliFx.
-- Added generic `CliApplicationBuilder.AddCommand<TCommand>()`. This overload simplifies adding commands one-by-one as it also checks that the type implements `ICommand`.
-
-## v1.3.2 (31-Jul-2020)
-
-- Fixed an issue where a command was incorrectly allowed to execute when the user did not specify any value for a non-scalar parameter. Since they are always required, a parameter needs to be bound to at least one value. (Thanks [@Daniel Hix](https://github.com/ADustyOldMuffin))
-- Fixed an issue where `CliApplication.RunAsync(...)` threw `ArgumentException` if there were two environment variables, whose names differed only in case. Environment variable names are now treated case-sensitively. (Thanks [@Ron Myers](https://github.com/ron-myers))
-
-## v1.3.1 (19-Jul-2020)
-
-- Running the application with the debug directive (`myapp [debug]`) will now also try to launch a debugger instance. In most cases it will save time as you won't need to attach the debugger manually. (Thanks [@Volodymyr Shkolka](https://github.com/BlackGad))
-- Fixed an issue where unhandled generic exceptions (i.e. not `CommandException`) sometimes caused the application to incorrectly return successful exit code due to an overflow issue on Unix systems. Starting from this version, all unhandled generic exceptions will produce `1` as the exit code when thrown. Instances of `CommandException` can still be configured to return any specified exit code, but it's recommended to constrain the values between `1` and `255` to avoid overflow issues. (Thanks [@Ihor Nechyporuk](https://github.com/inech))
-
-## v1.3 (23-May-2020)
-
-- Changed analyzers to report errors instead of warnings. If you find that some analyzer works incorrectly, please report it on GitHub. You can also configure inspection severity overrides in your project if you need to.
-- Improved help text by showing default values for non-required options. This only works on types that have a custom override for `ToString()` method. Additionally, if the type implements `IFormattable`, the overload with a format provider will be used instead. (Thanks [@Domn Werner](https://github.com/domn1995))
-- Changed default version text to only show 3 version components instead of 4, if the last component (revision) is not specified or is zero. This makes the default version text compliant with semantic versioning.
-- Fixed an issue where it was possible to define a command with an option that has the same name or short name as built-in help or version options. Previously it would lead to the user-defined option being ignored in favor of the built-in option. Now this will throw an exception instead.
-- Changed the underlying representation of `StreamReader`/`StreamWriter` objects used in `SystemConsole` and `VirtualConsole` to be thread-safe.
-
-## v1.2 (11-May-2020)
-
-- Added built-in Roslyn analyzers that help catch incorrect usage of the library. Currently, all analyzers report issues as warnings so as to not prevent the project from building. In the future that may change.
-- Added an optional parameter to `new CommandException(...)` called `showHelp` which can be used to instruct CliFx to show help for the current command after printing the error. (Thanks [@Domn Werner](https://github.com/domn1995))
-- Improved help text shown for enum options and parameters by providing the list of valid values that the enum can accept. (Thanks [@Domn Werner](https://github.com/domn1995))
-- Fixed an issue where it was possible to set an option without providing a value, while the option was marked as required.
-- Fixed an issue where it was possible to configure an option with an empty name or a name consisting of a single character. If you want to use a single character as a name, you should set the option's short name instead.
-- Added `CursorLeft` and `CursorTop` properties to `IConsole` and its implementations. In `VirtualConsole`, these are just auto-properties.
-- Improved exception messages.
-- Improved exceptions related to user input by also showing help text after the error message. (Thanks [@Domn Werner](https://github.com/domn1995))
-
-## v1.1 (16-Mar-2020)
-
-- Changed `IConsole` interface (and as a result, `SystemConsole` and `VirtualConsole`) to support writing binary data. Instead of `TextReader`/`TextWriter` instances, the streams are now exposed as `StreamReader`/`StreamWriter` which provide the `BaseStream` property that allows raw access. Existing usages inside commands should remain the same because `StreamReader`/`StreamWriter` are compatible with their base classes `TextReader`/`TextWriter`, but if you were using `VirtualConsole` in tests, you may have to update it to the new API. Refer to the readme for more info.
-- Changed argument binding behavior so that an error is produced if the user provides an argument that doesn't match with any parameter or option. This is done in order to improve user experience, as otherwise the user may make a typo without knowing that their input wasn't taken into account.
-- Changed argument binding behavior so that options can be set to multiple argument values while specifying them with mixed naming. For example, `--option value1 -o value2 --option value3` would result in the option being set to corresponding three values, assuming `--option` and `-o` match with the same option.

CliFx.Analyzers.Tests/CliFx.Analyzers.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -9,15 +9,15 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.5" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net80" Version="1.8.0" />
-    <PackageReference Include="coverlet.collector" Version="6.0.0" PrivateAssets="all" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
-    <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" PrivateAssets="all" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="2.4.1" PrivateAssets="all" />
-    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="FluentAssertions" Version="8.0.1" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.7.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.11.0" />
-    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" PrivateAssets="all" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.1" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Analyzers.Tests/GeneralSpecs.cs

@@ -13,8 +13,7 @@ public class GeneralSpecs
     {
         // Arrange
         var analyzers = typeof(AnalyzerBase)
-            .Assembly
+            .Assembly.GetTypes()
-            .GetTypes()
             .Where(t => !t.IsAbstract && t.IsAssignableTo(typeof(DiagnosticAnalyzer)))
             .Select(t => (DiagnosticAnalyzer)Activator.CreateInstance(t)!)
             .ToArray();

CliFx.Analyzers.Tests/OptionMustHaveValidValidatorsAnalyzerSpecs.cs

@@ -23,7 +23,7 @@ public class OptionMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
+                [CommandOption("foo", Validators = new[] { typeof(MyValidator) })]
                 public string? Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -48,7 +48,7 @@ public class OptionMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
+                [CommandOption("foo", Validators = new[] { typeof(MyValidator) })]
                 public string? Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -73,7 +73,7 @@ public class OptionMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
+                [CommandOption("foo", Validators = new[] { typeof(MyValidator) })]
                 public string? Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;

CliFx.Analyzers.Tests/ParameterMustHaveValidValidatorsAnalyzerSpecs.cs

@@ -23,7 +23,7 @@ public class ParameterMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+                [CommandParameter(0, Validators = new[] { typeof(MyValidator) })]
                 public required string Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -48,7 +48,7 @@ public class ParameterMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+                [CommandParameter(0, Validators = new[] { typeof(MyValidator) })]
                 public required string Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -73,7 +73,7 @@ public class ParameterMustHaveValidValidatorsAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+                [CommandParameter(0, Validators = new[] { typeof(MyValidator) })]
                 public required string Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;

CliFx.Analyzers.Tests/SystemConsoleShouldBeAvoidedAnalyzerSpecs.cs

@@ -83,7 +83,7 @@ public class SystemConsoleShouldBeAvoidedAnalyzerSpecs
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Hello world");
+                    console.WriteLine("Hello world");
                     return default;
                 }
             }

CliFx.Analyzers.Tests/Utils/AnalyzerAssertions.cs

@@ -13,12 +13,12 @@ using Microsoft.CodeAnalysis.Text;
 
 namespace CliFx.Analyzers.Tests.Utils;
 
-internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer, AnalyzerAssertions>
+internal class AnalyzerAssertions(DiagnosticAnalyzer analyzer, AssertionChain assertionChain)
+    : ReferenceTypeAssertions<DiagnosticAnalyzer, AnalyzerAssertions>(analyzer, assertionChain)
 {
-    protected override string Identifier { get; } = "analyzer";
+    private readonly AssertionChain _assertionChain = assertionChain;
 
-    public AnalyzerAssertions(DiagnosticAnalyzer analyzer)
+    protected override string Identifier => "analyzer";
-        : base(analyzer) { }
 
     private Compilation Compile(string sourceCode)
     {
@@ -27,13 +27,12 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         {
             "System",
             "System.Collections.Generic",
-            "System.Threading.Tasks"
+            "System.Threading.Tasks",
         };
 
         // Get default CliFx namespaces
         var defaultCliFxNamespaces = typeof(ICommand)
-            .Assembly
+            .Assembly.GetTypes()
-            .GetTypes()
             .Where(t => t.IsPublic)
             .Select(t => t.Namespace)
             .Distinct()
@@ -49,17 +48,16 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         // Parse the source code
         var ast = SyntaxFactory.ParseSyntaxTree(
             SourceText.From(sourceCodeWithUsings),
-            CSharpParseOptions.Default
+            CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.Preview)
         );
 
         // Compile the code to IL
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
-            new[] { ast },
+            [ast],
-            Net70
+            Net80.References.All.Append(
-                .References
+                MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location)
-                .All
+            ),
-                .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location)),
             // DLL to avoid having to define the Main() method
             new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
         );
@@ -106,8 +104,7 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
             expectedDiagnosticIds.Intersect(producedDiagnosticIds).Count()
             == expectedDiagnosticIds.Length;
 
-        Execute
+        _assertionChain
-            .Assertion
             .ForCondition(isSuccessfulAssertion)
             .FailWith(() =>
             {
@@ -151,8 +148,7 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         var producedDiagnostics = GetProducedDiagnostics(sourceCode);
         var isSuccessfulAssertion = !producedDiagnostics.Any();
 
-        Execute
+        _assertionChain
-            .Assertion
             .ForCondition(isSuccessfulAssertion)
             .FailWith(() =>
             {
@@ -176,5 +172,6 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
 
 internal static class AnalyzerAssertionsExtensions
 {
-    public static AnalyzerAssertions Should(this DiagnosticAnalyzer analyzer) => new(analyzer);
+    public static AnalyzerAssertions Should(this DiagnosticAnalyzer analyzer) =>
+        new(analyzer, AssertionChain.GetOrCreate());
 }

CliFx.Analyzers/CliFx.Analyzers.csproj

@@ -17,11 +17,11 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
     <!-- Make sure to target the lowest possible version of the compiler for wider support -->
     <PackageReference Include="Microsoft.CodeAnalysis" Version="3.0.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.0.0" PrivateAssets="all" />
-    <PackageReference Include="PolyShim" Version="1.8.0" PrivateAssets="all" />
+    <PackageReference Include="PolyShim" Version="1.14.0" PrivateAssets="all" />
   </ItemGroup>
 
 </Project>

CliFx.Analyzers/CommandMustBeAnnotatedAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class CommandMustBeAnnotatedAnalyzer : AnalyzerBase
+public class CommandMustBeAnnotatedAnalyzer()
-{
+    : AnalyzerBase(
-    public CommandMustBeAnnotatedAnalyzer()
-        : base(
         $"Commands must be annotated with `{SymbolNames.CliFxCommandAttribute}`",
         $"This type must be annotated with `{SymbolNames.CliFxCommandAttribute}` in order to be a valid command."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         ClassDeclarationSyntax classDeclaration,
@@ -28,8 +26,8 @@ public class CommandMustBeAnnotatedAnalyzer : AnalyzerBase
         if (type.IsAbstract)
             return;
 
-        var implementsCommandInterface = type.AllInterfaces.Any(
+        var implementsCommandInterface = type.AllInterfaces.Any(i =>
-            i => i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
+            i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
         );
 
         var hasCommandAttribute = type.GetAttributes()

CliFx.Analyzers/CommandMustImplementInterfaceAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class CommandMustImplementInterfaceAnalyzer : AnalyzerBase
+public class CommandMustImplementInterfaceAnalyzer()
-{
+    : AnalyzerBase(
-    public CommandMustImplementInterfaceAnalyzer()
-        : base(
         $"Commands must implement `{SymbolNames.CliFxCommandInterface}` interface",
         $"This type must implement `{SymbolNames.CliFxCommandInterface}` interface in order to be a valid command."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         ClassDeclarationSyntax classDeclaration,
@@ -26,8 +24,8 @@ public class CommandMustImplementInterfaceAnalyzer : AnalyzerBase
             .Select(a => a.AttributeClass)
             .Any(c => c.DisplayNameMatches(SymbolNames.CliFxCommandAttribute));
 
-        var implementsCommandInterface = type.AllInterfaces.Any(
+        var implementsCommandInterface = type.AllInterfaces.Any(i =>
-            i => i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
+            i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
         );
 
         // If the attribute is present, but the interface is not implemented,

CliFx.Analyzers/ObjectModel/CommandOptionSymbol.cs

@@ -5,36 +5,26 @@ using Microsoft.CodeAnalysis;
 
 namespace CliFx.Analyzers.ObjectModel;
 
-internal partial class CommandOptionSymbol : ICommandMemberSymbol
+internal partial class CommandOptionSymbol(
-{
-    public IPropertySymbol Property { get; }
-
-    public string? Name { get; }
-
-    public char? ShortName { get; }
-
-    public bool? IsRequired { get; }
-
-    public ITypeSymbol? ConverterType { get; }
-
-    public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; }
-
-    public CommandOptionSymbol(
     IPropertySymbol property,
     string? name,
     char? shortName,
     bool? isRequired,
     ITypeSymbol? converterType,
     IReadOnlyList<ITypeSymbol> validatorTypes
-    )
+) : ICommandMemberSymbol
-    {
+{
-        Property = property;
+    public IPropertySymbol Property { get; } = property;
-        Name = name;
+
-        ShortName = shortName;
+    public string? Name { get; } = name;
-        IsRequired = isRequired;
+
-        ConverterType = converterType;
+    public char? ShortName { get; } = shortName;
-        ValidatorTypes = validatorTypes;
+
-    }
+    public bool? IsRequired { get; } = isRequired;
+
+    public ITypeSymbol? ConverterType { get; } = converterType;
+
+    public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; } = validatorTypes;
 }
 
 internal partial class CommandOptionSymbol
@@ -42,8 +32,7 @@ internal partial class CommandOptionSymbol
     private static AttributeData? TryGetOptionAttribute(IPropertySymbol property) =>
         property
             .GetAttributes()
-            .FirstOrDefault(
+            .FirstOrDefault(a =>
-                a =>
                 a.AttributeClass?.DisplayNameMatches(SymbolNames.CliFxCommandOptionAttribute)
                 == true
             );
@@ -56,35 +45,30 @@ internal partial class CommandOptionSymbol
 
         var name =
             attribute
-                .ConstructorArguments
+                .ConstructorArguments.Where(a => a.Type?.SpecialType == SpecialType.System_String)
-                .Where(a => a.Type?.SpecialType == SpecialType.System_String)
                 .Select(a => a.Value)
                 .FirstOrDefault() as string;
 
         var shortName =
             attribute
-                .ConstructorArguments
+                .ConstructorArguments.Where(a => a.Type?.SpecialType == SpecialType.System_Char)
-                .Where(a => a.Type?.SpecialType == SpecialType.System_Char)
                 .Select(a => a.Value)
                 .FirstOrDefault() as char?;
 
         var isRequired =
             attribute
-                .NamedArguments
+                .NamedArguments.Where(a => a.Key == "IsRequired")
-                .Where(a => a.Key == "IsRequired")
                 .Select(a => a.Value.Value)
                 .FirstOrDefault() as bool?;
 
         var converter = attribute
-            .NamedArguments
+            .NamedArguments.Where(a => a.Key == "Converter")
-            .Where(a => a.Key == "Converter")
             .Select(a => a.Value.Value)
             .Cast<ITypeSymbol?>()
             .FirstOrDefault();
 
         var validators = attribute
-            .NamedArguments
+            .NamedArguments.Where(a => a.Key == "Validators")
-            .Where(a => a.Key == "Validators")
             .SelectMany(a => a.Value.Values)
             .Select(c => c.Value)
             .Cast<ITypeSymbol>()

CliFx.Analyzers/ObjectModel/CommandParameterSymbol.cs

@@ -5,36 +5,26 @@ using Microsoft.CodeAnalysis;
 
 namespace CliFx.Analyzers.ObjectModel;
 
-internal partial class CommandParameterSymbol : ICommandMemberSymbol
+internal partial class CommandParameterSymbol(
-{
-    public IPropertySymbol Property { get; }
-
-    public int Order { get; }
-
-    public string? Name { get; }
-
-    public bool? IsRequired { get; }
-
-    public ITypeSymbol? ConverterType { get; }
-
-    public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; }
-
-    public CommandParameterSymbol(
     IPropertySymbol property,
     int order,
     string? name,
     bool? isRequired,
     ITypeSymbol? converterType,
     IReadOnlyList<ITypeSymbol> validatorTypes
-    )
+) : ICommandMemberSymbol
-    {
+{
-        Property = property;
+    public IPropertySymbol Property { get; } = property;
-        Order = order;
+
-        Name = name;
+    public int Order { get; } = order;
-        IsRequired = isRequired;
+
-        ConverterType = converterType;
+    public string? Name { get; } = name;
-        ValidatorTypes = validatorTypes;
+
-    }
+    public bool? IsRequired { get; } = isRequired;
+
+    public ITypeSymbol? ConverterType { get; } = converterType;
+
+    public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; } = validatorTypes;
 }
 
 internal partial class CommandParameterSymbol
@@ -42,8 +32,7 @@ internal partial class CommandParameterSymbol
     private static AttributeData? TryGetParameterAttribute(IPropertySymbol property) =>
         property
             .GetAttributes()
-            .FirstOrDefault(
+            .FirstOrDefault(a =>
-                a =>
                 a.AttributeClass?.DisplayNameMatches(SymbolNames.CliFxCommandParameterAttribute)
                 == true
             );
@@ -58,28 +47,24 @@ internal partial class CommandParameterSymbol
 
         var name =
             attribute
-                .NamedArguments
+                .NamedArguments.Where(a => a.Key == "Name")
-                .Where(a => a.Key == "Name")
                 .Select(a => a.Value.Value)
                 .FirstOrDefault() as string;
 
         var isRequired =
             attribute
-                .NamedArguments
+                .NamedArguments.Where(a => a.Key == "IsRequired")
-                .Where(a => a.Key == "IsRequired")
                 .Select(a => a.Value.Value)
                 .FirstOrDefault() as bool?;
 
         var converter = attribute
-            .NamedArguments
+            .NamedArguments.Where(a => a.Key == "Converter")
-            .Where(a => a.Key == "Converter")
             .Select(a => a.Value.Value)
             .Cast<ITypeSymbol?>()
             .FirstOrDefault();
 
         var validators = attribute
-            .NamedArguments
+            .NamedArguments.Where(a => a.Key == "Validators")
-            .Where(a => a.Key == "Validators")
             .SelectMany(a => a.Value.Values)
             .Select(c => c.Value)
             .Cast<ITypeSymbol>()

CliFx.Analyzers/OptionMustBeInsideCommandAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustBeInsideCommandAnalyzer : AnalyzerBase
+public class OptionMustBeInsideCommandAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustBeInsideCommandAnalyzer()
-        : base(
         "Options must be defined inside commands",
         $"This option must be defined inside a class that implements `{SymbolNames.CliFxCommandInterface}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -31,10 +29,9 @@ public class OptionMustBeInsideCommandAnalyzer : AnalyzerBase
         if (!CommandOptionSymbol.IsOptionProperty(property))
             return;
 
-        var isInsideCommand = property
+        var isInsideCommand = property.ContainingType.AllInterfaces.Any(i =>
-            .ContainingType
+            i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
-            .AllInterfaces
+        );
-            .Any(i => i.DisplayNameMatches(SymbolNames.CliFxCommandInterface));
 
         if (!isInsideCommand)
         {

CliFx.Analyzers/OptionMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -7,14 +7,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustBeRequiredIfPropertyRequiredAnalyzer : AnalyzerBase
+public class OptionMustBeRequiredIfPropertyRequiredAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustBeRequiredIfPropertyRequiredAnalyzer()
-        : base(
         "Options bound to required properties cannot be marked as non-required",
         "This option cannot be marked as non-required because it's bound to a required property."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,

CliFx.Analyzers/OptionMustHaveNameOrShortNameAnalyzer.cs

@@ -7,14 +7,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveNameOrShortNameAnalyzer : AnalyzerBase
+public class OptionMustHaveNameOrShortNameAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveNameOrShortNameAnalyzer()
-        : base(
         "Options must have either a name or short name specified",
         "This option must have either a name or short name specified."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,

CliFx.Analyzers/OptionMustHaveUniqueNameAnalyzer.cs

@@ -9,16 +9,14 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveUniqueNameAnalyzer : AnalyzerBase
+public class OptionMustHaveUniqueNameAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveUniqueNameAnalyzer()
-        : base(
         "Options must have unique names",
         "This option's name must be unique within the command (comparison IS NOT case sensitive). "
             + "Specified name: `{0}`. "
             + "Property bound to another option with the same name: `{1}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -36,8 +34,7 @@ public class OptionMustHaveUniqueNameAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/OptionMustHaveUniqueShortNameAnalyzer.cs

@@ -8,16 +8,14 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveUniqueShortNameAnalyzer : AnalyzerBase
+public class OptionMustHaveUniqueShortNameAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveUniqueShortNameAnalyzer()
-        : base(
         "Options must have unique short names",
         "This option's short name must be unique within the command (comparison IS case sensitive). "
             + "Specified short name: `{0}` "
             + "Property bound to another option with the same short name: `{1}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -35,8 +33,7 @@ public class OptionMustHaveUniqueShortNameAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/OptionMustHaveValidConverterAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveValidConverterAnalyzer : AnalyzerBase
+public class OptionMustHaveValidConverterAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveValidConverterAnalyzer()
-        : base(
         $"Option converters must derive from `{SymbolNames.CliFxBindingConverterClass}`",
         $"Converter specified for this option must derive from a compatible `{SymbolNames.CliFxBindingConverterClass}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -30,13 +28,11 @@ public class OptionMustHaveValidConverterAnalyzer : AnalyzerBase
             return;
 
         var converterValueType = option
-            .ConverterType
+            .ConverterType.GetBaseTypes()
-            .GetBaseTypes()
+            .FirstOrDefault(t =>
-            .FirstOrDefault(
+                t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingConverterClass)
-                t => t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingConverterClass)
             )
-            ?.TypeArguments
+            ?.TypeArguments.FirstOrDefault();
-            .FirstOrDefault();
 
         // Value returned by the converter must be assignable to the property type
         var isCompatible =
@@ -47,9 +43,10 @@ public class OptionMustHaveValidConverterAnalyzer : AnalyzerBase
                     ? context.Compilation.IsAssignable(converterValueType, property.Type)
                     // Non-scalar (assume we can handle all IEnumerable types for simplicity)
                     : property.Type.TryGetEnumerableUnderlyingType() is { } enumerableUnderlyingType
-                        && context
+                        && context.Compilation.IsAssignable(
-                            .Compilation
+                            converterValueType,
-                            .IsAssignable(converterValueType, enumerableUnderlyingType)
+                            enumerableUnderlyingType
+                        )
             );
 
         if (!isCompatible)

CliFx.Analyzers/OptionMustHaveValidNameAnalyzer.cs

@@ -7,15 +7,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveValidNameAnalyzer : AnalyzerBase
+public class OptionMustHaveValidNameAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveValidNameAnalyzer()
-        : base(
         "Options must have valid names",
         "This option's name must be at least 2 characters long and must start with a letter. "
             + "Specified name: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,

CliFx.Analyzers/OptionMustHaveValidShortNameAnalyzer.cs

@@ -7,15 +7,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveValidShortNameAnalyzer : AnalyzerBase
+public class OptionMustHaveValidShortNameAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveValidShortNameAnalyzer()
-        : base(
         "Option short names must be letter characters",
         "This option's short name must be a single letter character. "
             + "Specified short name: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,

CliFx.Analyzers/OptionMustHaveValidValidatorsAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class OptionMustHaveValidValidatorsAnalyzer : AnalyzerBase
+public class OptionMustHaveValidValidatorsAnalyzer()
-{
+    : AnalyzerBase(
-    public OptionMustHaveValidValidatorsAnalyzer()
-        : base(
         $"Option validators must derive from `{SymbolNames.CliFxBindingValidatorClass}`",
         $"Each validator specified for this option must derive from a compatible `{SymbolNames.CliFxBindingValidatorClass}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -30,12 +28,10 @@ public class OptionMustHaveValidValidatorsAnalyzer : AnalyzerBase
         {
             var validatorValueType = validatorType
                 .GetBaseTypes()
-                .FirstOrDefault(
+                .FirstOrDefault(t =>
-                    t =>
                     t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingValidatorClass)
                 )
-                ?.TypeArguments
+                ?.TypeArguments.FirstOrDefault();
-                .FirstOrDefault();
 
             // Value passed to the validator must be assignable from the property type
             var isCompatible =

CliFx.Analyzers/ParameterMustBeInsideCommandAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeInsideCommandAnalyzer : AnalyzerBase
+public class ParameterMustBeInsideCommandAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeInsideCommandAnalyzer()
-        : base(
         "Parameters must be defined inside commands",
         $"This parameter must be defined inside a class that implements `{SymbolNames.CliFxCommandInterface}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -31,10 +29,9 @@ public class ParameterMustBeInsideCommandAnalyzer : AnalyzerBase
         if (!CommandParameterSymbol.IsParameterProperty(property))
             return;
 
-        var isInsideCommand = property
+        var isInsideCommand = property.ContainingType.AllInterfaces.Any(i =>
-            .ContainingType
+            i.DisplayNameMatches(SymbolNames.CliFxCommandInterface)
-            .AllInterfaces
+        );
-            .Any(i => i.DisplayNameMatches(SymbolNames.CliFxCommandInterface));
 
         if (!isInsideCommand)
         {

CliFx.Analyzers/ParameterMustBeLastIfNonRequiredAnalyzer.cs

@@ -8,15 +8,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeLastIfNonRequiredAnalyzer : AnalyzerBase
+public class ParameterMustBeLastIfNonRequiredAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeLastIfNonRequiredAnalyzer()
-        : base(
         "Parameters marked as non-required must be the last in order",
         "This parameter is non-required so it must be the last in order (its order must be highest within the command). "
             + "Property bound to another non-required parameter: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -34,8 +32,7 @@ public class ParameterMustBeLastIfNonRequiredAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustBeLastIfNonScalarAnalyzer.cs

@@ -8,15 +8,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeLastIfNonScalarAnalyzer : AnalyzerBase
+public class ParameterMustBeLastIfNonScalarAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeLastIfNonScalarAnalyzer()
-        : base(
         "Parameters of non-scalar types must be the last in order",
         "This parameter has a non-scalar type so it must be the last in order (its order must be highest within the command). "
             + "Property bound to another non-scalar parameter: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -34,8 +32,7 @@ public class ParameterMustBeLastIfNonScalarAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -7,14 +7,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeRequiredIfPropertyRequiredAnalyzer : AnalyzerBase
+public class ParameterMustBeRequiredIfPropertyRequiredAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeRequiredIfPropertyRequiredAnalyzer()
-        : base(
         "Parameters bound to required properties cannot be marked as non-required",
         "This parameter cannot be marked as non-required because it's bound to a required property."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,

CliFx.Analyzers/ParameterMustBeSingleIfNonRequiredAnalyzer.cs

@@ -8,15 +8,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeSingleIfNonRequiredAnalyzer : AnalyzerBase
+public class ParameterMustBeSingleIfNonRequiredAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeSingleIfNonRequiredAnalyzer()
-        : base(
         "Parameters marked as non-required are limited to one per command",
         "This parameter is non-required so it must be the only such parameter in the command. "
             + "Property bound to another non-required parameter: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -34,8 +32,7 @@ public class ParameterMustBeSingleIfNonRequiredAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustBeSingleIfNonScalarAnalyzer.cs

@@ -8,15 +8,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustBeSingleIfNonScalarAnalyzer : AnalyzerBase
+public class ParameterMustBeSingleIfNonScalarAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustBeSingleIfNonScalarAnalyzer()
-        : base(
         "Parameters of non-scalar types are limited to one per command",
         "This parameter has a non-scalar type so it must be the only such parameter in the command. "
             + "Property bound to another non-scalar parameter: `{0}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -34,8 +32,7 @@ public class ParameterMustBeSingleIfNonScalarAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustHaveUniqueNameAnalyzer.cs

@@ -9,16 +9,14 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustHaveUniqueNameAnalyzer : AnalyzerBase
+public class ParameterMustHaveUniqueNameAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustHaveUniqueNameAnalyzer()
-        : base(
         "Parameters must have unique names",
         "This parameter's name must be unique within the command (comparison IS NOT case sensitive). "
             + "Specified name: `{0}`. "
             + "Property bound to another parameter with the same name: `{1}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -36,8 +34,7 @@ public class ParameterMustHaveUniqueNameAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustHaveUniqueOrderAnalyzer.cs

@@ -8,16 +8,14 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustHaveUniqueOrderAnalyzer : AnalyzerBase
+public class ParameterMustHaveUniqueOrderAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustHaveUniqueOrderAnalyzer()
-        : base(
         "Parameters must have unique order",
         "This parameter's order must be unique within the command. "
             + "Specified order: {0}. "
             + "Property bound to another parameter with the same order: `{1}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -32,8 +30,7 @@ public class ParameterMustHaveUniqueOrderAnalyzer : AnalyzerBase
             return;
 
         var otherProperties = property
-            .ContainingType
+            .ContainingType.GetMembers()
-            .GetMembers()
             .OfType<IPropertySymbol>()
             .Where(m => !m.Equals(property))
             .ToArray();

CliFx.Analyzers/ParameterMustHaveValidConverterAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustHaveValidConverterAnalyzer : AnalyzerBase
+public class ParameterMustHaveValidConverterAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustHaveValidConverterAnalyzer()
-        : base(
         $"Parameter converters must derive from `{SymbolNames.CliFxBindingConverterClass}`",
         $"Converter specified for this parameter must derive from a compatible `{SymbolNames.CliFxBindingConverterClass}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -30,13 +28,11 @@ public class ParameterMustHaveValidConverterAnalyzer : AnalyzerBase
             return;
 
         var converterValueType = parameter
-            .ConverterType
+            .ConverterType.GetBaseTypes()
-            .GetBaseTypes()
+            .FirstOrDefault(t =>
-            .FirstOrDefault(
+                t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingConverterClass)
-                t => t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingConverterClass)
             )
-            ?.TypeArguments
+            ?.TypeArguments.FirstOrDefault();
-            .FirstOrDefault();
 
         // Value returned by the converter must be assignable to the property type
         var isCompatible =
@@ -47,9 +43,10 @@ public class ParameterMustHaveValidConverterAnalyzer : AnalyzerBase
                     ? context.Compilation.IsAssignable(converterValueType, property.Type)
                     // Non-scalar (assume we can handle all IEnumerable types for simplicity)
                     : property.Type.TryGetEnumerableUnderlyingType() is { } enumerableUnderlyingType
-                        && context
+                        && context.Compilation.IsAssignable(
-                            .Compilation
+                            converterValueType,
-                            .IsAssignable(converterValueType, enumerableUnderlyingType)
+                            enumerableUnderlyingType
+                        )
             );
 
         if (!isCompatible)

CliFx.Analyzers/ParameterMustHaveValidValidatorsAnalyzer.cs

@@ -8,14 +8,12 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class ParameterMustHaveValidValidatorsAnalyzer : AnalyzerBase
+public class ParameterMustHaveValidValidatorsAnalyzer()
-{
+    : AnalyzerBase(
-    public ParameterMustHaveValidValidatorsAnalyzer()
-        : base(
         $"Parameter validators must derive from `{SymbolNames.CliFxBindingValidatorClass}`",
         $"Each validator specified for this parameter must derive from a compatible `{SymbolNames.CliFxBindingValidatorClass}`."
-        ) { }
+    )
-
+{
     private void Analyze(
         SyntaxNodeAnalysisContext context,
         PropertyDeclarationSyntax propertyDeclaration,
@@ -30,12 +28,10 @@ public class ParameterMustHaveValidValidatorsAnalyzer : AnalyzerBase
         {
             var validatorValueType = validatorType
                 .GetBaseTypes()
-                .FirstOrDefault(
+                .FirstOrDefault(t =>
-                    t =>
                     t.ConstructedFrom.DisplayNameMatches(SymbolNames.CliFxBindingValidatorClass)
                 )
-                ?.TypeArguments
+                ?.TypeArguments.FirstOrDefault();
-                .FirstOrDefault();
 
             // Value passed to the validator must be assignable from the property type
             var isCompatible =

CliFx.Analyzers/SystemConsoleShouldBeAvoidedAnalyzer.cs

@@ -9,15 +9,13 @@ using Microsoft.CodeAnalysis.Diagnostics;
 namespace CliFx.Analyzers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-public class SystemConsoleShouldBeAvoidedAnalyzer : AnalyzerBase
+public class SystemConsoleShouldBeAvoidedAnalyzer()
-{
+    : AnalyzerBase(
-    public SystemConsoleShouldBeAvoidedAnalyzer()
-        : base(
         $"Avoid calling `System.Console` where `{SymbolNames.CliFxConsoleInterface}` is available",
         $"Use the provided `{SymbolNames.CliFxConsoleInterface}` abstraction instead of `System.Console` to ensure that the command can be tested in isolation.",
         DiagnosticSeverity.Warning
-        ) { }
+    )
-
+{
     private MemberAccessExpressionSyntax? TryGetSystemConsoleMemberAccess(
         SyntaxNodeAnalysisContext context,
         SyntaxNode node
@@ -54,8 +52,7 @@ public class SystemConsoleShouldBeAvoidedAnalyzer : AnalyzerBase
 
         // Check if IConsole is available in scope as an alternative to System.Console
         var isConsoleInterfaceAvailable = context
-            .Node
+            .Node.Ancestors()
-            .Ancestors()
             .OfType<MethodDeclarationSyntax>()
             .SelectMany(m => m.ParameterList.Parameters)
             .Select(p => p.Type)

CliFx.Analyzers/Utils/Extensions/RoslynExtensions.cs

@@ -30,9 +30,8 @@ internal static class RoslynExtensions
     }
 
     public static ITypeSymbol? TryGetEnumerableUnderlyingType(this ITypeSymbol type) =>
-        type.AllInterfaces
+        type
-            .FirstOrDefault(
+            .AllInterfaces.FirstOrDefault(i =>
-                i =>
                 i.ConstructedFrom.SpecialType
                 == SpecialType.System_Collections_Generic_IEnumerable_T
             )
@@ -44,8 +43,7 @@ internal static class RoslynExtensions
         property
             // Can't rely on the RequiredMemberAttribute because it's generated by the compiler, not added by the user,
             // so we have to check for the presence of the `required` modifier in the syntax tree instead.
-            .DeclaringSyntaxReferences
+            .DeclaringSyntaxReferences.Select(r => r.GetSyntax())
-            .Select(r => r.GetSyntax())
             .OfType<PropertyDeclarationSyntax>()
             .SelectMany(p => p.Modifiers)
             .Any(m => m.IsKind((SyntaxKind)8447));

CliFx.Benchmarks/Benchmarks.Cocona.cs

@@ -8,9 +8,9 @@ public partial class Benchmarks
     public class CoconaCommand
     {
         public void Execute(
-            [Option("str", new[] { 's' })] string? strOption,
+            [Option("str", ['s'])] string? strOption,
-            [Option("int", new[] { 'i' })] int intOption,
+            [Option("int", ['i'])] int intOption,
-            [Option("bool", new[] { 'b' })] bool boolOption
+            [Option("bool", ['b'])] bool boolOption
         ) { }
     }
 

CliFx.Benchmarks/Benchmarks.SystemCommandLine.cs

@@ -1,5 +1,4 @@
 using System.CommandLine;
-using System.CommandLine.Invocation;
 using System.Threading.Tasks;
 using BenchmarkDotNet.Attributes;
 
@@ -9,20 +8,20 @@ public partial class Benchmarks
 {
     public class SystemCommandLineCommand
     {
-        public static int ExecuteHandler(string s, int i, bool b) => 0;
+        public static void ExecuteHandler(string s, int i, bool b) { }
 
         public Task<int> ExecuteAsync(string[] args)
         {
-            var command = new RootCommand
+            var stringOption = new Option<string>(["--str", "-s"]);
-            {
+            var intOption = new Option<int>(["--int", "-i"]);
-                new Option(new[] { "--str", "-s" }) { Argument = new Argument<string?>() },
+            var boolOption = new Option<bool>(["--bool", "-b"]);
-                new Option(new[] { "--int", "-i" }) { Argument = new Argument<int>() },
-                new Option(new[] { "--bool", "-b" }) { Argument = new Argument<bool>() }
-            };
 
-            command.Handler = CommandHandler.Create(
+            var command = new RootCommand();
-                typeof(SystemCommandLineCommand).GetMethod(nameof(ExecuteHandler))!
+            command.AddOption(stringOption);
-            );
+            command.AddOption(intOption);
+            command.AddOption(boolOption);
+
+            command.SetHandler(ExecuteHandler, stringOption, intOption, boolOption);
 
             return command.InvokeAsync(args);
         }

CliFx.Benchmarks/Benchmarks.cs

@@ -9,7 +9,7 @@ namespace CliFx.Benchmarks;
 [Orderer(SummaryOrderPolicy.FastestToSlowest)]
 public partial class Benchmarks
 {
-    private static readonly string[] Arguments = { "--str", "hello world", "-i", "13", "-b" };
+    private static readonly string[] Arguments = ["--str", "hello world", "-i", "13", "-b"];
 
     public static void Main() =>
         BenchmarkRunner.Run<Benchmarks>(

CliFx.Benchmarks/CliFx.Benchmarks.csproj

@@ -2,18 +2,19 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
+    <NuGetAudit>false</NuGetAudit>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.10" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.14.0" />
     <PackageReference Include="clipr" Version="1.6.1" />
     <PackageReference Include="Cocona" Version="2.2.0" />
     <PackageReference Include="CommandLineParser" Version="2.9.1" />
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
-    <PackageReference Include="McMaster.Extensions.CommandLineUtils" Version="4.1.0" />
+    <PackageReference Include="McMaster.Extensions.CommandLineUtils" Version="4.1.1" />
     <PackageReference Include="PowerArgs" Version="4.0.3" />
-    <PackageReference Include="System.CommandLine" Version="2.0.0-beta1.20574.7" />
+    <PackageReference Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Demo/CliFx.Demo.csproj

@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <ApplicationIcon>../favicon.ico</ApplicationIcon>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.1" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Demo/Commands/BookAddCommand.cs

@@ -9,10 +9,8 @@ using CliFx.Infrastructure;
 namespace CliFx.Demo.Commands;
 
 [Command("book add", Description = "Adds a book to the library.")]
-public partial class BookAddCommand : ICommand
+public class BookAddCommand(LibraryProvider libraryProvider) : ICommand
 {
-    private readonly LibraryProvider _libraryProvider;
-
     [CommandParameter(0, Name = "title", Description = "Book title.")]
     public required string Title { get; init; }
 
@@ -20,52 +18,38 @@ public partial class BookAddCommand : ICommand
     public required string Author { get; init; }
 
     [CommandOption("published", 'p', Description = "Book publish date.")]
-    public DateTimeOffset Published { get; init; } = CreateRandomDate();
+    public DateTimeOffset Published { get; init; } =
+        new(
+            Random.Shared.Next(1800, 2020),
+            Random.Shared.Next(1, 12),
+            Random.Shared.Next(1, 28),
+            Random.Shared.Next(1, 23),
+            Random.Shared.Next(1, 59),
+            Random.Shared.Next(1, 59),
+            TimeSpan.Zero
+        );
 
     [CommandOption("isbn", 'n', Description = "Book ISBN.")]
-    public Isbn Isbn { get; init; } = CreateRandomIsbn();
+    public Isbn Isbn { get; init; } =
-
+        new(
-    public BookAddCommand(LibraryProvider libraryProvider)
+            Random.Shared.Next(0, 999),
-    {
+            Random.Shared.Next(0, 99),
-        _libraryProvider = libraryProvider;
+            Random.Shared.Next(0, 99999),
-    }
+            Random.Shared.Next(0, 99),
+            Random.Shared.Next(0, 9)
+        );
 
     public ValueTask ExecuteAsync(IConsole console)
     {
-        if (_libraryProvider.TryGetBook(Title) is not null)
+        if (libraryProvider.TryGetBook(Title) is not null)
-            throw new CommandException("Book already exists.", 10);
+            throw new CommandException($"Book '{Title}' already exists.", 10);
 
         var book = new Book(Title, Author, Published, Isbn);
-        _libraryProvider.AddBook(book);
+        libraryProvider.AddBook(book);
 
-        console.Output.WriteLine("Book added.");
+        console.WriteLine($"Book '{Title}' added.");
-        console.Output.WriteBook(book);
+        console.WriteBook(book);
 
         return default;
     }
 }
-
-public partial class BookAddCommand
-{
-    private static readonly Random Random = new();
-
-    private static DateTimeOffset CreateRandomDate() =>
-        new(
-            Random.Next(1800, 2020),
-            Random.Next(1, 12),
-            Random.Next(1, 28),
-            Random.Next(1, 23),
-            Random.Next(1, 59),
-            Random.Next(1, 59),
-            TimeSpan.Zero
-        );
-
-    private static Isbn CreateRandomIsbn() =>
-        new(
-            Random.Next(0, 999),
-            Random.Next(0, 99),
-            Random.Next(0, 99999),
-            Random.Next(0, 99),
-            Random.Next(0, 9)
-        );
-}

CliFx.Demo/Commands/BookCommand.cs

@@ -8,26 +8,19 @@ using CliFx.Infrastructure;
 namespace CliFx.Demo.Commands;
 
 [Command("book", Description = "Retrieves a book from the library.")]
-public class BookCommand : ICommand
+public class BookCommand(LibraryProvider libraryProvider) : ICommand
 {
-    private readonly LibraryProvider _libraryProvider;
-
     [CommandParameter(0, Name = "title", Description = "Title of the book to retrieve.")]
     public required string Title { get; init; }
 
-    public BookCommand(LibraryProvider libraryProvider)
-    {
-        _libraryProvider = libraryProvider;
-    }
-
     public ValueTask ExecuteAsync(IConsole console)
     {
-        var book = _libraryProvider.TryGetBook(Title);
+        var book = libraryProvider.TryGetBook(Title);
 
         if (book is null)
-            throw new CommandException("Book not found.", 10);
+            throw new CommandException($"Book '{Title}' not found.", 10);
 
-        console.Output.WriteBook(book);
+        console.WriteBook(book);
 
         return default;
     }

CliFx.Demo/Commands/BookListCommand.cs

@@ -7,28 +7,21 @@ using CliFx.Infrastructure;
 namespace CliFx.Demo.Commands;
 
 [Command("book list", Description = "Lists all books in the library.")]
-public class BookListCommand : ICommand
+public class BookListCommand(LibraryProvider libraryProvider) : ICommand
 {
-    private readonly LibraryProvider _libraryProvider;
-
-    public BookListCommand(LibraryProvider libraryProvider)
-    {
-        _libraryProvider = libraryProvider;
-    }
-
     public ValueTask ExecuteAsync(IConsole console)
     {
-        var library = _libraryProvider.GetLibrary();
+        var library = libraryProvider.GetLibrary();
 
         for (var i = 0; i < library.Books.Count; i++)
         {
             // Add margin
             if (i != 0)
-                console.Output.WriteLine();
+                console.WriteLine();
 
             // Render book
             var book = library.Books[i];
-            console.Output.WriteBook(book);
+            console.WriteBook(book);
         }
 
         return default;

CliFx.Demo/Commands/BookRemoveCommand.cs

@@ -7,28 +7,21 @@ using CliFx.Infrastructure;
 namespace CliFx.Demo.Commands;
 
 [Command("book remove", Description = "Removes a book from the library.")]
-public class BookRemoveCommand : ICommand
+public class BookRemoveCommand(LibraryProvider libraryProvider) : ICommand
 {
-    private readonly LibraryProvider _libraryProvider;
-
     [CommandParameter(0, Name = "title", Description = "Title of the book to remove.")]
     public required string Title { get; init; }
 
-    public BookRemoveCommand(LibraryProvider libraryProvider)
-    {
-        _libraryProvider = libraryProvider;
-    }
-
     public ValueTask ExecuteAsync(IConsole console)
     {
-        var book = _libraryProvider.TryGetBook(Title);
+        var book = libraryProvider.TryGetBook(Title);
 
         if (book is null)
-            throw new CommandException("Book not found.", 10);
+            throw new CommandException($"Book '{Title}' not found.", 10);
 
-        _libraryProvider.RemoveBook(book);
+        libraryProvider.RemoveBook(book);
 
-        console.Output.WriteLine($"Book {Title} removed.");
+        console.WriteLine($"Book '{Title}' removed.");
 
         return default;
     }

CliFx.Demo/Utils/ConsoleExtensions.cs

@@ -33,4 +33,7 @@ internal static class ConsoleExtensions
         using (writer.Console.WithForegroundColor(ConsoleColor.White))
             writer.WriteLine(book.Isbn);
     }
+
+    public static void WriteBook(this IConsole console, Book book) =>
+        console.Output.WriteBook(book);
 }

CliFx.Tests.Dummy/CliFx.Tests.Dummy.csproj

@@ -2,12 +2,12 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <ApplicationIcon>../favicon.ico</ApplicationIcon>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Tests.Dummy/Commands/CancellationTestCommand.cs

@@ -12,15 +12,15 @@ public class CancellationTestCommand : ICommand
     {
         try
         {
-            console.Output.WriteLine("Started.");
+            console.WriteLine("Started.");
 
             await Task.Delay(TimeSpan.FromSeconds(3), console.RegisterCancellationHandler());
 
-            console.Output.WriteLine("Completed.");
+            console.WriteLine("Completed.");
         }
         catch (OperationCanceledException)
         {
-            console.Output.WriteLine("Cancelled.");
+            console.WriteLine("Cancelled.");
             throw;
         }
     }

CliFx.Tests.Dummy/Commands/EnvironmentTestCommand.cs

@@ -12,8 +12,7 @@ public class EnvironmentTestCommand : ICommand
 
     public ValueTask ExecuteAsync(IConsole console)
     {
-        console.Output.WriteLine($"Hello {GreetingTarget}!");
+        console.WriteLine($"Hello {GreetingTarget}!");
-
         return default;
     }
 }

CliFx.Tests/ApplicationSpecs.cs

@@ -8,11 +8,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class ApplicationSpecs : SpecsBase
+public class ApplicationSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public ApplicationSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_create_an_application_with_the_default_configuration()
     {
@@ -35,8 +32,8 @@ public class ApplicationSpecs : SpecsBase
         var app = new CliApplicationBuilder()
             .AddCommand<NoOpCommand>()
             .AddCommandsFrom(typeof(NoOpCommand).Assembly)
-            .AddCommands(new[] { typeof(NoOpCommand) })
+            .AddCommands([typeof(NoOpCommand)])
-            .AddCommandsFrom(new[] { typeof(NoOpCommand).Assembly })
+            .AddCommandsFrom([typeof(NoOpCommand).Assembly])
             .AddCommandsFromThisAssembly()
             .AllowDebugMode()
             .AllowPreviewMode()

CliFx.Tests/CancellationSpecs.cs

@@ -12,11 +12,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class CancellationSpecs : SpecsBase
+public class CancellationSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public CancellationSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact(Timeout = 15000)]
     public async Task I_can_configure_the_command_to_listen_to_the_interrupt_signal()
     {
@@ -69,18 +66,18 @@ public class CancellationSpecs : SpecsBase
                 {
                     try
                     {
-                        console.Output.WriteLine("Started.");
+                        console.WriteLine("Started.");
 
                         await Task.Delay(
                             TimeSpan.FromSeconds(3),
                             console.RegisterCancellationHandler()
                         );
 
-                        console.Output.WriteLine("Completed.");
+                        console.WriteLine("Completed.");
                     }
                     catch (OperationCanceledException)
                     {
-                        console.Output.WriteLine("Cancelled.");
+                        console.WriteLine("Cancelled.");
                         throw;
                     }
                 }

CliFx.Tests/CliFx.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -9,18 +9,18 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.5" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net80" Version="1.8.0" />
-    <PackageReference Include="CliWrap" Version="3.6.4" />
+    <PackageReference Include="CliWrap" Version="3.7.1" />
-    <PackageReference Include="coverlet.collector" Version="6.0.0" PrivateAssets="all" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
-    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="FluentAssertions" Version="8.0.1" />
-    <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" PrivateAssets="all" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="2.4.1" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.7.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.11.0" />
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.1" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="PolyShim" Version="1.8.0" PrivateAssets="all" />
+    <PackageReference Include="PolyShim" Version="1.14.0" PrivateAssets="all" />
-    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" PrivateAssets="all" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.1" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Tests/ConsoleSpecs.cs

@@ -14,11 +14,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class ConsoleSpecs : SpecsBase
+public class ConsoleSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public ConsoleSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact(Timeout = 15000)]
     public async Task I_can_run_the_application_with_the_default_console_implementation_to_interact_with_the_system_console()
     {
@@ -173,9 +170,9 @@ public class ConsoleSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(console.ReadKey().Key);
+                    console.WriteLine(console.ReadKey().Key);
-                    console.Output.WriteLine(console.ReadKey().Key);
+                    console.WriteLine(console.ReadKey().Key);
-                    console.Output.WriteLine(console.ReadKey().Key);
+                    console.WriteLine(console.ReadKey().Key);
 
                     return default;
                 }

CliFx.Tests/ConversionSpecs.cs

@@ -8,11 +8,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class ConversionSpecs : SpecsBase
+public class ConversionSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public ConversionSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_bind_a_parameter_or_an_option_to_a_string_property()
     {
@@ -28,7 +25,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -41,10 +38,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "xyz"], new Dictionary<string, string>());
-            new[] { "-f", "xyz" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -68,7 +62,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -81,10 +75,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "xyz"], new Dictionary<string, string>());
-            new[] { "-f", "xyz" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -114,9 +105,9 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
-                    console.Output.WriteLine("Baz = " + Baz);
+                    console.WriteLine("Baz = " + Baz);
 
                     return default;
                 }
@@ -131,7 +122,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "true", "-b", "false", "-c" },
+            ["-f", "true", "-b", "false", "-c"],
             new Dictionary<string, string>()
         );
 
@@ -157,7 +148,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -170,10 +161,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "32"], new Dictionary<string, string>());
-            new[] { "-f", "32" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -197,7 +185,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo.ToString(CultureInfo.InvariantCulture));
+                    console.WriteLine(Foo.ToString(CultureInfo.InvariantCulture));
                     return default;
                 }
             }
@@ -211,7 +199,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "32.14" },
+            ["-f", "32.14"],
             new Dictionary<string, string>()
         );
 
@@ -237,7 +225,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo.ToString("u", CultureInfo.InvariantCulture));
+                    console.WriteLine(Foo.ToString("u", CultureInfo.InvariantCulture));
                     return default;
                 }
             }
@@ -251,7 +239,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "1995-04-28Z" },
+            ["-f", "1995-04-28Z"],
             new Dictionary<string, string>()
         );
 
@@ -277,7 +265,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo.ToString(null, CultureInfo.InvariantCulture));
+                    console.WriteLine(Foo.ToString(null, CultureInfo.InvariantCulture));
                     return default;
                 }
             }
@@ -291,7 +279,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "12:34:56" },
+            ["-f", "12:34:56"],
             new Dictionary<string, string>()
         );
 
@@ -319,7 +307,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine((int) Foo);
+                    console.WriteLine((int) Foo);
                     return default;
                 }
             }
@@ -332,10 +320,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "two"], new Dictionary<string, string>());
-            new[] { "-f", "two" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -362,8 +347,8 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -377,10 +362,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-b", "123"], new Dictionary<string, string>());
-            new[] { "-b", "123" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -409,8 +391,8 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + (int?) Foo);
+                    console.WriteLine("Foo = " + (int?) Foo);
-                    console.Output.WriteLine("Bar = " + (int?) Bar);
+                    console.WriteLine("Bar = " + (int?) Bar);
 
                     return default;
                 }
@@ -424,10 +406,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-b", "two"], new Dictionary<string, string>());
-            new[] { "-b", "two" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -458,7 +437,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo.Value);
+                    console.WriteLine(Foo.Value);
                     return default;
                 }
             }
@@ -471,10 +450,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "xyz"], new Dictionary<string, string>());
-            new[] { "-f", "xyz" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -521,8 +497,8 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo.Value);
+                    console.WriteLine("Foo = " + Foo.Value);
-                    console.Output.WriteLine("Bar = " + Bar.Value);
+                    console.WriteLine("Bar = " + Bar.Value);
 
                     return default;
                 }
@@ -537,7 +513,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "hello", "-b", "world" },
+            ["-f", "hello", "-b", "world"],
             new Dictionary<string, string>()
         );
 
@@ -569,7 +545,7 @@ public class ConversionSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -583,7 +559,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "hello world" },
+            ["-f", "hello world"],
             new Dictionary<string, string>()
         );
 
@@ -610,7 +586,7 @@ public class ConversionSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -625,7 +601,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "two", "three" },
+            ["-f", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 
@@ -652,7 +628,7 @@ public class ConversionSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -667,7 +643,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "two", "three" },
+            ["-f", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 
@@ -694,7 +670,7 @@ public class ConversionSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -709,7 +685,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "two", "three" },
+            ["-f", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 
@@ -736,7 +712,7 @@ public class ConversionSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -751,7 +727,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "1", "13", "27" },
+            ["-f", "1", "13", "27"],
             new Dictionary<string, string>()
         );
 
@@ -790,10 +766,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "xyz"], new Dictionary<string, string>());
-            new[] { "-f", "xyz" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -834,7 +807,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "two" },
+            ["-f", "one", "two"],
             new Dictionary<string, string>()
         );
 
@@ -870,7 +843,7 @@ public class ConversionSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "12.34" },
+            ["-f", "12.34"],
             new Dictionary<string, string>()
         );
 
@@ -901,7 +874,7 @@ public class ConversionSpecs : SpecsBase
             [Command]
             public class Command : ICommand
             {
-                [CommandOption('f', Validators = new[] {typeof(ValidatorA), typeof(ValidatorB)})]
+                [CommandOption('f', Validators = [typeof(ValidatorA), typeof(ValidatorB)])]
                 public int Foo { get; init; }
 
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -915,10 +888,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "12"], new Dictionary<string, string>());
-            new[] { "-f", "12" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -960,10 +930,7 @@ public class ConversionSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["-f", "bar"], new Dictionary<string, string>());
-            new[] { "-f", "bar" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);

CliFx.Tests/DirectivesSpecs.cs

@@ -11,11 +11,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class DirectivesSpecs : SpecsBase
+public class DirectivesSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public DirectivesSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact(Timeout = 15000)]
     public async Task I_can_use_the_debug_directive_to_make_the_application_wait_for_the_debugger_to_attach()
     {
@@ -66,7 +63,7 @@ public class DirectivesSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "[preview]", "cmd", "param", "-abc", "--option", "foo" },
+            ["[preview]", "cmd", "param", "-abc", "--option", "foo"],
             new Dictionary<string, string> { ["ENV_QOP"] = "hello", ["ENV_KIL"] = "world" }
         );
 

CliFx.Tests/EnvironmentSpecs.cs

@@ -12,11 +12,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class EnvironmentSpecs : SpecsBase
+public class EnvironmentSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public EnvironmentSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_configure_an_option_to_fall_back_to_an_environment_variable_if_the_user_does_not_provide_the_corresponding_argument()
     {
@@ -35,8 +32,8 @@ public class EnvironmentSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
-                    console.Output.WriteLine(Bar);
+                    console.WriteLine(Bar);
 
                     return default;
                 }
@@ -51,7 +48,7 @@ public class EnvironmentSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "42" },
+            ["--foo", "42"],
             new Dictionary<string, string> { ["ENV_FOO"] = "100", ["ENV_BAR"] = "200" }
         );
 
@@ -78,7 +75,7 @@ public class EnvironmentSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -119,7 +116,7 @@ public class EnvironmentSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }

CliFx.Tests/ErrorReportingSpecs.cs

@@ -9,11 +9,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class ErrorReportingSpecs : SpecsBase
+public class ErrorReportingSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public ErrorReportingSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_throw_an_exception_in_a_command_to_report_an_error_with_a_stacktrace()
     {

CliFx.Tests/HelpTextSpecs.cs

@@ -9,11 +9,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class HelpTextSpecs : SpecsBase
+public class HelpTextSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public HelpTextSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_request_the_help_text_by_running_the_application_without_arguments_if_the_default_command_is_not_defined()
     {
@@ -58,10 +55,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -98,10 +92,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -144,7 +135,7 @@ public class HelpTextSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "cmd", "--help" },
+            ["cmd", "--help"],
             new Dictionary<string, string>()
         );
 
@@ -189,7 +180,7 @@ public class HelpTextSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "cmd", "sub", "--help" },
+            ["cmd", "sub", "--help"],
             new Dictionary<string, string>()
         );
 
@@ -212,7 +203,7 @@ public class HelpTextSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "invalid-command", "--invalid-option" },
+            ["invalid-command", "--invalid-option"],
             new Dictionary<string, string>()
         );
 
@@ -238,10 +229,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -271,10 +259,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -310,10 +295,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -352,10 +334,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -401,10 +380,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -443,10 +419,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -484,10 +457,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -526,10 +496,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -569,7 +536,7 @@ public class HelpTextSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "cmd", "--help" },
+            ["cmd", "--help"],
             new Dictionary<string, string>()
         );
 
@@ -612,10 +579,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -668,10 +632,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -724,10 +685,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -780,10 +738,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -849,10 +804,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -930,10 +882,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -1004,10 +953,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--help"], new Dictionary<string, string>());
-            new[] { "--help" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -1038,10 +984,7 @@ public class HelpTextSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--version"], new Dictionary<string, string>());
-            new[] { "--version" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);

CliFx.Tests/OptionBindingSpecs.cs

@@ -9,11 +9,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class OptionBindingSpecs : SpecsBase
+public class OptionBindingSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public OptionBindingSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_bind_an_option_to_a_property_and_get_the_value_from_the_corresponding_argument_by_name()
     {
@@ -29,7 +26,7 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -42,10 +39,7 @@ public class OptionBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--foo"], new Dictionary<string, string>());
-            new[] { "--foo" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -69,7 +63,7 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -82,7 +76,7 @@ public class OptionBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(new[] { "-f" }, new Dictionary<string, string>());
+        var exitCode = await application.RunAsync(["-f"], new Dictionary<string, string>());
 
         // Assert
         exitCode.Should().Be(0);
@@ -109,8 +103,8 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -125,7 +119,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "--bar", "two" },
+            ["--foo", "one", "--bar", "two"],
             new Dictionary<string, string>()
         );
 
@@ -154,8 +148,8 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -170,7 +164,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "-b", "two" },
+            ["-f", "one", "-b", "two"],
             new Dictionary<string, string>()
         );
 
@@ -199,8 +193,8 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -215,7 +209,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-fb", "value" },
+            ["-fb", "value"],
             new Dictionary<string, string>()
         );
 
@@ -242,7 +236,7 @@ public class OptionBindingSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -257,7 +251,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "two", "three" },
+            ["--foo", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 
@@ -284,7 +278,7 @@ public class OptionBindingSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -299,7 +293,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "two", "three" },
+            ["-f", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 
@@ -326,7 +320,7 @@ public class OptionBindingSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -341,7 +335,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "--foo", "two", "--foo", "three" },
+            ["--foo", "one", "--foo", "two", "--foo", "three"],
             new Dictionary<string, string>()
         );
 
@@ -368,7 +362,7 @@ public class OptionBindingSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -383,7 +377,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "-f", "one", "-f", "two", "-f", "three" },
+            ["-f", "one", "-f", "two", "-f", "three"],
             new Dictionary<string, string>()
         );
 
@@ -410,7 +404,7 @@ public class OptionBindingSpecs : SpecsBase
                 public ValueTask ExecuteAsync(IConsole console)
                 {
                     foreach (var i in Foo)
-                        console.Output.WriteLine(i);
+                        console.WriteLine(i);
 
                     return default;
                 }
@@ -425,7 +419,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "-f", "two", "--foo", "three" },
+            ["--foo", "one", "-f", "two", "--foo", "three"],
             new Dictionary<string, string>()
         );
 
@@ -454,8 +448,8 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -470,7 +464,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one" },
+            ["--foo", "one"],
             new Dictionary<string, string>()
         );
 
@@ -528,9 +522,9 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + SharedContext.Foo);
+                    console.WriteLine("Foo = " + SharedContext.Foo);
-                    console.Output.WriteLine("Bar = " + SharedContext.Bar);
+                    console.WriteLine("Bar = " + SharedContext.Bar);
-                    console.Output.WriteLine("Baz = " + Baz);
+                    console.WriteLine("Baz = " + Baz);
 
                     return default;
                 }
@@ -544,7 +538,7 @@ public class OptionBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(new[] { "--foo", "42", "--bar", "--baz", "xyz" });
+        var exitCode = await application.RunAsync(["--foo", "42", "--bar", "--baz", "xyz"]);
 
         // Assert
         exitCode.Should().Be(0);
@@ -568,7 +562,7 @@ public class OptionBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(Foo);
+                    console.WriteLine(Foo);
                     return default;
                 }
             }
@@ -582,7 +576,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "-13" },
+            ["--foo", "-13"],
             new Dictionary<string, string>()
         );
 
@@ -653,10 +647,7 @@ public class OptionBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--foo"], new Dictionary<string, string>());
-            new[] { "--foo" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -689,10 +680,7 @@ public class OptionBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["--foo"], new Dictionary<string, string>());
-            new[] { "--foo" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -726,7 +714,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "--bar", "two" },
+            ["--foo", "one", "--bar", "two"],
             new Dictionary<string, string>()
         );
 
@@ -762,7 +750,7 @@ public class OptionBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "--foo", "one", "two", "three" },
+            ["--foo", "one", "two", "three"],
             new Dictionary<string, string>()
         );
 

CliFx.Tests/ParameterBindingSpecs.cs

@@ -8,11 +8,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class ParameterBindingSpecs : SpecsBase
+public class ParameterBindingSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public ParameterBindingSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_bind_a_parameter_to_a_property_and_get_the_value_from_the_corresponding_argument()
     {
@@ -31,8 +28,8 @@ public class ParameterBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -46,10 +43,7 @@ public class ParameterBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["one", "two"], new Dictionary<string, string>());
-            new[] { "one", "two" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -82,11 +76,11 @@ public class ParameterBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     foreach (var i in Baz)
-                        console.Output.WriteLine("Baz = " + i);
+                        console.WriteLine("Baz = " + i);
 
                     return default;
                 }
@@ -101,7 +95,7 @@ public class ParameterBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "one", "two", "three", "four", "five", "--boo", "xxx" },
+            ["one", "two", "three", "four", "five", "--boo", "xxx"],
             new Dictionary<string, string>()
         );
 
@@ -141,10 +135,7 @@ public class ParameterBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["one"], new Dictionary<string, string>());
-            new[] { "one" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -180,10 +171,7 @@ public class ParameterBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["one"], new Dictionary<string, string>());
-            new[] { "one" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().NotBe(0);
@@ -210,8 +198,8 @@ public class ParameterBindingSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("Foo = " + Foo);
+                    console.WriteLine("Foo = " + Foo);
-                    console.Output.WriteLine("Bar = " + Bar);
+                    console.WriteLine("Bar = " + Bar);
 
                     return default;
                 }
@@ -225,10 +213,7 @@ public class ParameterBindingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["abc"], new Dictionary<string, string>());
-            new[] { "abc" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -265,7 +250,7 @@ public class ParameterBindingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "one", "two", "three" },
+            ["one", "two", "three"],
             new Dictionary<string, string>()
         );
 

CliFx.Tests/RoutingSpecs.cs

@@ -8,11 +8,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class RoutingSpecs : SpecsBase
+public class RoutingSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public RoutingSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_configure_a_command_to_be_executed_by_default_when_the_user_does_not_specify_a_command_name()
     {
@@ -25,7 +22,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("default");
+                    console.WriteLine("default");
                     return default;
                 }
             }
@@ -35,7 +32,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd");
+                    console.WriteLine("cmd");
                     return default;
                 }
             }
@@ -45,7 +42,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd child");
+                    console.WriteLine("cmd child");
                     return default;
                 }
             }
@@ -82,7 +79,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("default");
+                    console.WriteLine("default");
                     return default;
                 }
             }
@@ -92,7 +89,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd");
+                    console.WriteLine("cmd");
                     return default;
                 }
             }
@@ -102,7 +99,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd child");
+                    console.WriteLine("cmd child");
                     return default;
                 }
             }
@@ -115,10 +112,7 @@ public class RoutingSpecs : SpecsBase
             .Build();
 
         // Act
-        var exitCode = await application.RunAsync(
+        var exitCode = await application.RunAsync(["cmd"], new Dictionary<string, string>());
-            new[] { "cmd" },
-            new Dictionary<string, string>()
-        );
 
         // Assert
         exitCode.Should().Be(0);
@@ -139,7 +133,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("default");
+                    console.WriteLine("default");
                     return default;
                 }
             }
@@ -149,7 +143,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd");
+                    console.WriteLine("cmd");
                     return default;
                 }
             }
@@ -159,7 +153,7 @@ public class RoutingSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("cmd child");
+                    console.WriteLine("cmd child");
                     return default;
                 }
             }
@@ -173,7 +167,7 @@ public class RoutingSpecs : SpecsBase
 
         // Act
         var exitCode = await application.RunAsync(
-            new[] { "cmd", "child" },
+            ["cmd", "child"],
             new Dictionary<string, string>()
         );
 

CliFx.Tests/SpecsBase.cs

@@ -5,14 +5,12 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public abstract class SpecsBase : IDisposable
+public abstract class SpecsBase(ITestOutputHelper testOutput) : IDisposable
 {
-    public ITestOutputHelper TestOutput { get; }
+    public ITestOutputHelper TestOutput { get; } = testOutput;
 
     public FakeInMemoryConsole FakeConsole { get; } = new();
 
-    protected SpecsBase(ITestOutputHelper testOutput) => TestOutput = testOutput;
-
     public void Dispose()
     {
         FakeConsole.DumpToTestOutput(TestOutput);

CliFx.Tests/TypeActivationSpecs.cs

@@ -10,11 +10,8 @@ using Xunit.Abstractions;
 
 namespace CliFx.Tests;
 
-public class TypeActivationSpecs : SpecsBase
+public class TypeActivationSpecs(ITestOutputHelper testOutput) : SpecsBase(testOutput)
 {
-    public TypeActivationSpecs(ITestOutputHelper testOutput)
-        : base(testOutput) { }
-
     [Fact]
     public async Task I_can_configure_the_application_to_use_the_default_type_activator_to_initialize_types_through_parameterless_constructors()
     {
@@ -27,7 +24,7 @@ public class TypeActivationSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("foo");
+                    console.WriteLine("foo");
                     return default;
                 }
             }
@@ -105,7 +102,7 @@ public class TypeActivationSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(_foo);
+                    console.WriteLine(_foo);
                     return default;
                 }
             }
@@ -147,7 +144,7 @@ public class TypeActivationSpecs : SpecsBase
 
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine(_foo);
+                    console.WriteLine(_foo);
                     return default;
                 }
             }
@@ -198,7 +195,7 @@ public class TypeActivationSpecs : SpecsBase
             {
                 public ValueTask ExecuteAsync(IConsole console)
                 {
-                    console.Output.WriteLine("foo");
+                    console.WriteLine("foo");
                     return default;
                 }
             }

CliFx.Tests/Utils/DynamicCommandBuilder.cs

@@ -27,13 +27,12 @@ internal static class DynamicCommandBuilder
             "System.Collections.Generic",
             "System.Linq",
             "System.Threading.Tasks",
-            "System.Globalization"
+            "System.Globalization",
         };
 
         // Get default CliFx namespaces
         var defaultCliFxNamespaces = typeof(ICommand)
-            .Assembly
+            .Assembly.GetTypes()
-            .GetTypes()
             .Where(t => t.IsPublic)
             .Select(t => t.Namespace)
             .Distinct()
@@ -49,17 +48,17 @@ internal static class DynamicCommandBuilder
         // Parse the source code
         var ast = SyntaxFactory.ParseSyntaxTree(
             SourceText.From(sourceCodeWithUsings),
-            CSharpParseOptions.Default
+            CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.Preview)
         );
 
         // Compile the code to IL
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
-            new[] { ast },
+            [ast],
-            Net70
+            Net80
-                .References
+                .References.All.Append(
-                .All
+                    MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location)
-                .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location))
+                )
                 .Append(
                     MetadataReference.CreateFromFile(
                         typeof(DynamicCommandBuilder).Assembly.Location
@@ -88,8 +87,8 @@ internal static class DynamicCommandBuilder
         using var buffer = new MemoryStream();
         var emit = compilation.Emit(buffer);
 
-        var emitErrors = emit.Diagnostics
+        var emitErrors = emit
-            .Where(d => d.Severity >= DiagnosticSeverity.Error)
+            .Diagnostics.Where(d => d.Severity >= DiagnosticSeverity.Error)
             .ToArray();
 
         if (emitErrors.Any())

CliFx.Tests/Utils/Extensions/AssertionExtensions.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using FluentAssertions;
-using FluentAssertions.Execution;
 using FluentAssertions.Primitives;
 
 namespace CliFx.Tests.Utils.Extensions;
@@ -10,17 +9,13 @@ internal static class AssertionExtensions
 {
     public static void ConsistOfLines(
         this StringAssertions assertions,
-        IEnumerable<string> lines
+        params IEnumerable<string> lines
     ) =>
         assertions
-            .Subject
+            .Subject.Split(['\n', '\r'], StringSplitOptions.RemoveEmptyEntries)
-            .Split(new[] { '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries)
             .Should()
             .Equal(lines);
 
-    public static void ConsistOfLines(this StringAssertions assertions, params string[] lines) =>
-        assertions.ConsistOfLines((IEnumerable<string>)lines);
-
     public static AndConstraint<StringAssertions> ContainAllInOrder(
         this StringAssertions assertions,
         IEnumerable<string> values
@@ -34,9 +29,7 @@ internal static class AssertionExtensions
 
             if (index < 0)
             {
-                Execute
+                assertions.CurrentAssertionChain.FailWith(
-                    .Assertion
-                    .FailWith(
                     $"Expected string '{assertions.Subject}' to contain '{value}' after position {lastIndex}."
                 );
             }

CliFx.sln

@@ -9,7 +9,6 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CliFx.Tests", "CliFx.Tests\
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{3AAE8166-BB8E-49DA-844C-3A0EE6BD40A0}"
 	ProjectSection(SolutionItems) = preProject
-		Changelog.md = Changelog.md
 		Directory.Build.props = Directory.Build.props
 		License.txt = License.txt
 		Readme.md = Readme.md

CliFx/ApplicationConfiguration.cs

@@ -6,34 +6,24 @@ namespace CliFx;
 /// <summary>
 /// Configuration of an application.
 /// </summary>
-public class ApplicationConfiguration
+public class ApplicationConfiguration(
+    IReadOnlyList<Type> commandTypes,
+    bool isDebugModeAllowed,
+    bool isPreviewModeAllowed
+)
 {
     /// <summary>
     /// Command types defined in the application.
     /// </summary>
-    public IReadOnlyList<Type> CommandTypes { get; }
+    public IReadOnlyList<Type> CommandTypes { get; } = commandTypes;
 
     /// <summary>
     /// Whether debug mode is allowed in the application.
     /// </summary>
-    public bool IsDebugModeAllowed { get; }
+    public bool IsDebugModeAllowed { get; } = isDebugModeAllowed;
 
     /// <summary>
     /// Whether preview mode is allowed in the application.
     /// </summary>
-    public bool IsPreviewModeAllowed { get; }
+    public bool IsPreviewModeAllowed { get; } = isPreviewModeAllowed;
-
-    /// <summary>
-    /// Initializes an instance of <see cref="ApplicationConfiguration" />.
-    /// </summary>
-    public ApplicationConfiguration(
-        IReadOnlyList<Type> commandTypes,
-        bool isDebugModeAllowed,
-        bool isPreviewModeAllowed
-    )
-    {
-        CommandTypes = commandTypes;
-        IsDebugModeAllowed = isDebugModeAllowed;
-        IsPreviewModeAllowed = isPreviewModeAllowed;
-    }
 }

CliFx/ApplicationMetadata.cs

@@ -3,41 +3,30 @@
 /// <summary>
 /// Metadata associated with an application.
 /// </summary>
-public class ApplicationMetadata
+public class ApplicationMetadata(
-{
-    /// <summary>
-    /// Application title.
-    /// </summary>
-    public string Title { get; }
-
-    /// <summary>
-    /// Application executable name.
-    /// </summary>
-    public string ExecutableName { get; }
-
-    /// <summary>
-    /// Application version.
-    /// </summary>
-    public string Version { get; }
-
-    /// <summary>
-    /// Application description.
-    /// </summary>
-    public string? Description { get; }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="ApplicationMetadata" />.
-    /// </summary>
-    public ApplicationMetadata(
     string title,
     string executableName,
     string version,
     string? description
-    )
+)
-    {
+{
-        Title = title;
+    /// <summary>
-        ExecutableName = executableName;
+    /// Application title.
-        Version = version;
+    /// </summary>
-        Description = description;
+    public string Title { get; } = title;
-    }
+
+    /// <summary>
+    /// Application executable name.
+    /// </summary>
+    public string ExecutableName { get; } = executableName;
+
+    /// <summary>
+    /// Application version.
+    /// </summary>
+    public string Version { get; } = version;
+
+    /// <summary>
+    /// Application description.
+    /// </summary>
+    public string? Description { get; } = description;
 }

CliFx/Attributes/CommandAttribute.cs

@@ -8,6 +8,16 @@ namespace CliFx.Attributes;
 [AttributeUsage(AttributeTargets.Class, Inherited = false)]
 public sealed class CommandAttribute : Attribute
 {
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandAttribute" />.
+    /// </summary>
+    public CommandAttribute(string name) => Name = name;
+
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandAttribute" />.
+    /// </summary>
+    public CommandAttribute() { }
+
     /// <summary>
     /// Command name.
     /// </summary>
@@ -23,17 +33,4 @@ public sealed class CommandAttribute : Attribute
     /// This is shown to the user in the help text.
     /// </summary>
     public string? Description { get; set; }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandAttribute" />.
-    /// </summary>
-    public CommandAttribute(string name)
-    {
-        Name = name;
-    }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandAttribute" />.
-    /// </summary>
-    public CommandAttribute() { }
 }

CliFx/Attributes/CommandOptionAttribute.cs

@@ -9,6 +9,33 @@ namespace CliFx.Attributes;
 [AttributeUsage(AttributeTargets.Property)]
 public sealed class CommandOptionAttribute : Attribute
 {
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
+    /// </summary>
+    private CommandOptionAttribute(string? name, char? shortName)
+    {
+        Name = name;
+        ShortName = shortName;
+    }
+
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
+    /// </summary>
+    public CommandOptionAttribute(string name, char shortName)
+        : this(name, (char?)shortName) { }
+
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
+    /// </summary>
+    public CommandOptionAttribute(string name)
+        : this(name, null) { }
+
+    /// <summary>
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
+    /// </summary>
+    public CommandOptionAttribute(char shortName)
+        : this(null, (char?)shortName) { }
+
     /// <summary>
     /// Option name.
     /// </summary>
@@ -67,31 +94,4 @@ public sealed class CommandOptionAttribute : Attribute
     /// Validators must derive from <see cref="BindingValidator{T}" />.
     /// </remarks>
     public Type[] Validators { get; set; } = Array.Empty<Type>();
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
-    /// </summary>
-    private CommandOptionAttribute(string? name, char? shortName)
-    {
-        Name = name;
-        ShortName = shortName;
-    }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
-    /// </summary>
-    public CommandOptionAttribute(string name, char shortName)
-        : this(name, (char?)shortName) { }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
-    /// </summary>
-    public CommandOptionAttribute(string name)
-        : this(name, null) { }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
-    /// </summary>
-    public CommandOptionAttribute(char shortName)
-        : this(null, (char?)shortName) { }
 }

CliFx/Attributes/CommandParameterAttribute.cs

@@ -7,7 +7,7 @@ namespace CliFx.Attributes;
 /// Annotates a property that defines a command parameter.
 /// </summary>
 [AttributeUsage(AttributeTargets.Property)]
-public sealed class CommandParameterAttribute : Attribute
+public sealed class CommandParameterAttribute(int order) : Attribute
 {
     /// <summary>
     /// Parameter order.
@@ -18,7 +18,7 @@ public sealed class CommandParameterAttribute : Attribute
     /// Parameter whose type is a non-scalar (e.g. array), must always be the last in order.
     /// Only one non-scalar parameter is allowed in a command.
     /// </remarks>
-    public int Order { get; }
+    public int Order { get; } = order;
 
     /// <summary>
     /// Whether this parameter is required (default: <c>true</c>).
@@ -62,12 +62,4 @@ public sealed class CommandParameterAttribute : Attribute
     /// Validators must derive from <see cref="BindingValidator{T}" />.
     /// </remarks>
     public Type[] Validators { get; set; } = Array.Empty<Type>();
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandParameterAttribute" />.
-    /// </summary>
-    public CommandParameterAttribute(int order)
-    {
-        Order = order;
-    }
 }

CliFx/CliApplication.cs

@@ -17,40 +17,24 @@ namespace CliFx;
 /// <summary>
 /// Command-line application facade.
 /// </summary>
-public class CliApplication
+public class CliApplication(
-{
-    /// <summary>
-    /// Application metadata.
-    /// </summary>
-    public ApplicationMetadata Metadata { get; }
-
-    /// <summary>
-    /// Application configuration.
-    /// </summary>
-    public ApplicationConfiguration Configuration { get; }
-
-    private readonly IConsole _console;
-    private readonly ITypeActivator _typeActivator;
-
-    private readonly CommandBinder _commandBinder;
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CliApplication" />.
-    /// </summary>
-    public CliApplication(
     ApplicationMetadata metadata,
     ApplicationConfiguration configuration,
     IConsole console,
     ITypeActivator typeActivator
-    )
+)
-    {
+{
-        Metadata = metadata;
+    private readonly CommandBinder _commandBinder = new(typeActivator);
-        Configuration = configuration;
-        _console = console;
-        _typeActivator = typeActivator;
 
-        _commandBinder = new CommandBinder(typeActivator);
+    /// <summary>
-    }
+    /// Application metadata.
+    /// </summary>
+    public ApplicationMetadata Metadata { get; } = metadata;
+
+    /// <summary>
+    /// Application configuration.
+    /// </summary>
+    public ApplicationConfiguration Configuration { get; } = configuration;
 
     private bool IsDebugModeEnabled(CommandInput commandInput) =>
         Configuration.IsDebugModeAllowed && commandInput.IsDebugDirectiveSpecified;
@@ -70,11 +54,9 @@ public class CliApplication
 
     private async ValueTask PromptDebuggerAsync()
     {
-        using (_console.WithForegroundColor(ConsoleColor.Green))
+        using (console.WithForegroundColor(ConsoleColor.Green))
         {
-            _console
+            console.Output.WriteLine(
-                .Output
-                .WriteLine(
                 $"Attach the debugger to process with ID {ProcessEx.GetCurrentProcessId()} to continue."
             );
         }
@@ -93,7 +75,7 @@ public class CliApplication
     {
         // Console colors may have already been overridden by the parent process,
         // so we need to reset it to make sure that everything we write looks properly.
-        _console.ResetColor();
+        console.ResetColor();
 
         // Handle the debug directive
         if (IsDebugModeEnabled(commandInput))
@@ -104,7 +86,7 @@ public class CliApplication
         // Handle the preview directive
         if (IsPreviewModeEnabled(commandInput))
         {
-            _console.Output.WriteCommandInput(commandInput);
+            console.WriteCommandInput(commandInput);
             return 0;
         }
 
@@ -128,7 +110,7 @@ public class CliApplication
         var commandInstance =
             commandSchema == FallbackDefaultCommand.Schema
                 ? new FallbackDefaultCommand() // bypass the activator
-                : _typeActivator.CreateInstance<ICommand>(commandSchema.Type);
+                : typeActivator.CreateInstance<ICommand>(commandSchema.Type);
 
         // Assemble the help context
         var helpContext = new HelpContext(
@@ -141,14 +123,14 @@ public class CliApplication
         // Handle the help option
         if (ShouldShowHelpText(commandSchema, commandInput))
         {
-            _console.Output.WriteHelpText(helpContext);
+            console.WriteHelpText(helpContext);
             return 0;
         }
 
         // Handle the version option
         if (ShouldShowVersionText(commandSchema, commandInput))
         {
-            _console.Output.WriteLine(Metadata.Version);
+            console.WriteLine(Metadata.Version);
             return 0;
         }
 
@@ -160,18 +142,18 @@ public class CliApplication
         {
             // Bind and execute the command
             _commandBinder.Bind(commandInput, commandSchema, commandInstance);
-            await commandInstance.ExecuteAsync(_console);
+            await commandInstance.ExecuteAsync(console);
 
             return 0;
         }
         catch (CliFxException ex)
         {
-            _console.Error.WriteException(ex);
+            console.WriteException(ex);
 
             if (ex.ShowHelp)
             {
-                _console.Output.WriteLine();
+                console.WriteLine();
-                _console.Output.WriteHelpText(helpContext);
+                console.WriteHelpText(helpContext);
             }
 
             return ex.ExitCode;
@@ -211,7 +193,7 @@ public class CliApplication
         // developer, so we don't swallow them in that case.
         catch (Exception ex) when (!Debugger.IsAttached)
         {
-            _console.Error.WriteException(ex);
+            console.WriteException(ex);
             return 1;
         }
     }

CliFx/CliApplicationBuilder.cs

@@ -16,7 +16,7 @@ namespace CliFx;
 /// </summary>
 public partial class CliApplicationBuilder
 {
-    private readonly HashSet<Type> _commandTypes = new();
+    private readonly HashSet<Type> _commandTypes = [];
 
     private bool _isDebugModeAllowed = true;
     private bool _isPreviewModeAllowed = true;
@@ -186,7 +186,8 @@ public partial class CliApplicationBuilder
     /// Configures the application to use the specified service provider for activating types.
     /// </summary>
     public CliApplicationBuilder UseTypeActivator(IServiceProvider serviceProvider) =>
-        UseTypeActivator(serviceProvider.GetService);
+        // Null returns are handled by DelegateTypeActivator
+        UseTypeActivator(serviceProvider.GetService!);
 
     /// <summary>
     /// Configures the application to use the specified service provider for activating types.

CliFx/CliFx.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net8.0</TargetFrameworks>
     <IsPackable>true</IsPackable>
   </PropertyGroup>
 
@@ -10,7 +10,7 @@
     <Description>Class-first framework for building command-line interfaces</Description>
     <PackageTags>command line executable interface framework parser arguments cli app application net core</PackageTags>
     <PackageProjectUrl>https://github.com/Tyrrrz/CliFx</PackageProjectUrl>
-    <PackageReleaseNotes>https://github.com/Tyrrrz/CliFx/blob/master/Changelog.md</PackageReleaseNotes>
+    <PackageReleaseNotes>https://github.com/Tyrrrz/CliFx/releases</PackageReleaseNotes>
     <PackageIcon>favicon.png</PackageIcon>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
@@ -21,10 +21,10 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="CSharpier.MsBuild" Version="0.26.1" PrivateAssets="all" />
+    <PackageReference Include="CSharpier.MsBuild" Version="0.30.6" PrivateAssets="all" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="all" />
-    <PackageReference Include="PolyShim" Version="1.8.0" PrivateAssets="all" />
+    <PackageReference Include="PolyShim" Version="1.14.0" PrivateAssets="all" />
-    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
+    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.6.0" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
   </ItemGroup>
 
   <!-- Embed the analyzer inside the package -->

CliFx/CommandBinder.cs

@@ -12,22 +12,16 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx;
 
-internal class CommandBinder
+internal class CommandBinder(ITypeActivator typeActivator)
 {
-    private readonly ITypeActivator _typeActivator;
     private readonly IFormatProvider _formatProvider = CultureInfo.InvariantCulture;
 
-    public CommandBinder(ITypeActivator typeActivator)
-    {
-        _typeActivator = typeActivator;
-    }
-
     private object? ConvertSingle(IMemberSchema memberSchema, string? rawValue, Type targetType)
     {
         // Custom converter
         if (memberSchema.ConverterType is not null)
         {
-            var converter = _typeActivator.CreateInstance<IBindingConverter>(
+            var converter = typeActivator.CreateInstance<IBindingConverter>(
                 memberSchema.ConverterType
             );
             return converter.Convert(rawValue);
@@ -48,13 +42,15 @@ internal class CommandBinder
         // Special case for DateTimeOffset
         if (targetType == typeof(DateTimeOffset))
         {
-            return DateTimeOffset.Parse(rawValue, _formatProvider);
+            // Null reference exception will be handled upstream
+            return DateTimeOffset.Parse(rawValue!, _formatProvider);
         }
 
         // Special case for TimeSpan
         if (targetType == typeof(TimeSpan))
         {
-            return TimeSpan.Parse(rawValue, _formatProvider);
+            // Null reference exception will be handled upstream
+            return TimeSpan.Parse(rawValue!, _formatProvider);
         }
 
         // Enum
@@ -80,27 +76,24 @@ internal class CommandBinder
         }
 
         // String-constructable (FileInfo, etc)
-        var stringConstructor = targetType.GetConstructor(new[] { typeof(string) });
+        var stringConstructor = targetType.GetConstructor([typeof(string)]);
         if (stringConstructor is not null)
         {
-            return stringConstructor.Invoke(new object?[] { rawValue });
+            return stringConstructor.Invoke([rawValue]);
         }
 
         // String-parseable (with IFormatProvider)
         var parseMethodWithFormatProvider = targetType.TryGetStaticParseMethod(true);
         if (parseMethodWithFormatProvider is not null)
         {
-            return parseMethodWithFormatProvider.Invoke(
+            return parseMethodWithFormatProvider.Invoke(null, [rawValue, _formatProvider]);
-                null,
-                new object?[] { rawValue, _formatProvider }
-            );
         }
 
         // String-parseable (without IFormatProvider)
         var parseMethod = targetType.TryGetStaticParseMethod();
         if (parseMethod is not null)
         {
-            return parseMethod.Invoke(null, new object?[] { rawValue });
+            return parseMethod.Invoke(null, [rawValue]);
         }
 
         throw CliFxException.InternalError(
@@ -132,10 +125,10 @@ internal class CommandBinder
         }
 
         // Array-constructable (List<T>, HashSet<T>, etc)
-        var arrayConstructor = targetEnumerableType.GetConstructor(new[] { arrayType });
+        var arrayConstructor = targetEnumerableType.GetConstructor([arrayType]);
         if (arrayConstructor is not null)
         {
-            return arrayConstructor.Invoke(new object?[] { array });
+            return arrayConstructor.Invoke([array]);
         }
 
         throw CliFxException.InternalError(
@@ -152,10 +145,8 @@ internal class CommandBinder
         try
         {
             // Non-scalar
-            var enumerableUnderlyingType = memberSchema
+            var enumerableUnderlyingType =
-                .Property
+                memberSchema.Property.Type.TryGetEnumerableUnderlyingType();
-                .Type
-                .TryGetEnumerableUnderlyingType();
 
             if (
                 enumerableUnderlyingType is not null
@@ -213,7 +204,7 @@ internal class CommandBinder
 
         foreach (var validatorType in memberSchema.ValidatorTypes)
         {
-            var validator = _typeActivator.CreateInstance<IBindingValidator>(validatorType);
+            var validator = typeActivator.CreateInstance<IBindingValidator>(validatorType);
             var error = validator.Validate(convertedValue);
 
             if (error is not null)
@@ -253,8 +244,7 @@ internal class CommandBinder
         // Ensure there are no unexpected parameters and that all parameters are provided
         var remainingParameterInputs = commandInput.Parameters.ToList();
         var remainingRequiredParameterSchemas = commandSchema
-            .Parameters
+            .Parameters.Where(p => p.IsRequired)
-            .Where(p => p.IsRequired)
             .ToList();
 
         var position = 0;
@@ -269,12 +259,9 @@ internal class CommandBinder
             if (parameterSchema.Property.IsScalar())
             {
                 var parameterInput = commandInput.Parameters[position];
-
+                BindMember(parameterSchema, commandInstance, [parameterInput.Value]);
-                var rawValues = new[] { parameterInput.Value };
-                BindMember(parameterSchema, commandInstance, rawValues);
 
                 position++;
-
                 remainingParameterInputs.Remove(parameterInput);
             }
             // Non-scalar: take all remaining inputs starting from the current position
@@ -282,11 +269,13 @@ internal class CommandBinder
             {
                 var parameterInputs = commandInput.Parameters.Skip(position).ToArray();
 
-                var rawValues = parameterInputs.Select(p => p.Value).ToArray();
+                BindMember(
-                BindMember(parameterSchema, commandInstance, rawValues);
+                    parameterSchema,
+                    commandInstance,
+                    parameterInputs.Select(p => p.Value).ToArray()
+                );
 
                 position += parameterInputs.Length;
-
                 remainingParameterInputs.RemoveRange(parameterInputs);
             }
 
@@ -308,7 +297,9 @@ internal class CommandBinder
             throw CliFxException.UserError(
                 $"""
                 Missing required parameter(s):
-                {remainingRequiredParameterSchemas.Select(p => p.GetFormattedIdentifier()).JoinToString(" ")}
+                {remainingRequiredParameterSchemas
+                    .Select(p => p.GetFormattedIdentifier())
+                    .JoinToString(" ")}
                 """
             );
         }
@@ -323,20 +314,18 @@ internal class CommandBinder
         // Ensure there are no unrecognized options and that all required options are set
         var remainingOptionInputs = commandInput.Options.ToList();
         var remainingRequiredOptionSchemas = commandSchema
-            .Options
+            .Options.Where(o => o.IsRequired)
-            .Where(o => o.IsRequired)
             .ToList();
 
         foreach (var optionSchema in commandSchema.Options)
         {
             var optionInputs = commandInput
-                .Options
+                .Options.Where(o => optionSchema.MatchesIdentifier(o.Identifier))
-                .Where(o => optionSchema.MatchesIdentifier(o.Identifier))
                 .ToArray();
 
-            var environmentVariableInput = commandInput
+            var environmentVariableInput = commandInput.EnvironmentVariables.FirstOrDefault(e =>
-                .EnvironmentVariables
+                optionSchema.MatchesEnvironmentVariable(e.Name)
-                .FirstOrDefault(e => optionSchema.MatchesEnvironmentVariable(e.Name));
+            );
 
             // Direct input
             if (optionInputs.Any())
@@ -353,7 +342,7 @@ internal class CommandBinder
             else if (environmentVariableInput is not null)
             {
                 var rawValues = optionSchema.Property.IsScalar()
-                    ? new[] { environmentVariableInput.Value }
+                    ? [environmentVariableInput.Value]
                     : environmentVariableInput.SplitValues();
 
                 BindMember(optionSchema, commandInstance, rawValues);
@@ -386,7 +375,9 @@ internal class CommandBinder
             throw CliFxException.UserError(
                 $"""
                 Missing required option(s):
-                {remainingRequiredOptionSchemas.Select(o => o.GetFormattedIdentifier()).JoinToString(", ")}
+                {remainingRequiredOptionSchemas
+                    .Select(o => o.GetFormattedIdentifier())
+                    .JoinToString(", ")}
                 """
             );
         }

CliFx/Exceptions/CliFxException.cs

@@ -5,7 +5,12 @@ namespace CliFx.Exceptions;
 /// <summary>
 /// Exception thrown when there is an error during application execution.
 /// </summary>
-public partial class CliFxException : Exception
+public partial class CliFxException(
+    string message,
+    int exitCode = CliFxException.DefaultExitCode,
+    bool showHelp = false,
+    Exception? innerException = null
+) : Exception(message, innerException)
 {
     internal const int DefaultExitCode = 1;
 
@@ -13,33 +18,17 @@ public partial class CliFxException : Exception
     // provides a default message that is not very useful.
     // This property is used to identify whether this instance was created with
     // a custom message, so that we can avoid printing the default message.
-    internal bool HasCustomMessage { get; }
+    internal bool HasCustomMessage { get; } = !string.IsNullOrWhiteSpace(message);
 
     /// <summary>
     /// Returned exit code.
     /// </summary>
-    public int ExitCode { get; }
+    public int ExitCode { get; } = exitCode;
 
     /// <summary>
     /// Whether to show the help text before exiting.
     /// </summary>
-    public bool ShowHelp { get; }
+    public bool ShowHelp { get; } = showHelp;
-
-    /// <summary>
-    /// Initializes an instance of <see cref="CliFxException" />.
-    /// </summary>
-    public CliFxException(
-        string message,
-        int exitCode = DefaultExitCode,
-        bool showHelp = false,
-        Exception? innerException = null
-    )
-        : base(message, innerException)
-    {
-        HasCustomMessage = !string.IsNullOrWhiteSpace(message);
-        ExitCode = exitCode;
-        ShowHelp = showHelp;
-    }
 }
 
 public partial class CliFxException

CliFx/Exceptions/CommandException.cs

@@ -6,16 +6,9 @@ namespace CliFx.Exceptions;
 /// Exception thrown when a command cannot proceed with its normal execution due to an error.
 /// Use this exception to report an error to the console and return a specific exit code.
 /// </summary>
-public class CommandException : CliFxException
+public class CommandException(
-{
-    /// <summary>
-    /// Initializes an instance of <see cref="CommandException" />.
-    /// </summary>
-    public CommandException(
     string message,
-        int exitCode = DefaultExitCode,
+    int exitCode = CliFxException.DefaultExitCode,
     bool showHelp = false,
     Exception? innerException = null
-    )
+) : CliFxException(message, exitCode, showHelp, innerException);
-        : base(message, exitCode, showHelp, innerException) { }
-}

CliFx/Extensibility/BindingValidationError.cs

@@ -3,15 +3,10 @@
 /// <summary>
 /// Represents a validation error.
 /// </summary>
-public class BindingValidationError
+public class BindingValidationError(string message)
 {
     /// <summary>
     /// Error message shown to the user.
     /// </summary>
-    public string Message { get; }
+    public string Message { get; } = message;
-
-    /// <summary>
-    /// Initializes an instance of <see cref="BindingValidationError" />.
-    /// </summary>
-    public BindingValidationError(string message) => Message = message;
 }

CliFx/Formatting/CommandInputConsoleFormatter.cs

@@ -4,11 +4,9 @@ using CliFx.Input;
 
 namespace CliFx.Formatting;
 
-internal class CommandInputConsoleFormatter : ConsoleFormatter
+internal class CommandInputConsoleFormatter(ConsoleWriter consoleWriter)
+    : ConsoleFormatter(consoleWriter)
 {
-    public CommandInputConsoleFormatter(ConsoleWriter consoleWriter)
-        : base(consoleWriter) { }
-
     private void WriteCommandLineArguments(CommandInput commandInput)
     {
         Write("Command-line:");
@@ -94,4 +92,7 @@ internal static class CommandInputConsoleFormatterExtensions
         this ConsoleWriter consoleWriter,
         CommandInput commandInput
     ) => new CommandInputConsoleFormatter(consoleWriter).WriteCommandInput(commandInput);
+
+    public static void WriteCommandInput(this IConsole console, CommandInput commandInput) =>
+        console.Output.WriteCommandInput(commandInput);
 }

CliFx/Formatting/ConsoleFormatter.cs

@@ -3,50 +3,46 @@ using CliFx.Infrastructure;
 
 namespace CliFx.Formatting;
 
-internal class ConsoleFormatter
+internal class ConsoleFormatter(ConsoleWriter consoleWriter)
 {
-    private readonly ConsoleWriter _consoleWriter;
-
     private int _column;
     private int _row;
 
     public bool IsEmpty => _column == 0 && _row == 0;
 
-    public ConsoleFormatter(ConsoleWriter consoleWriter) => _consoleWriter = consoleWriter;
-
     public void Write(string? value)
     {
-        _consoleWriter.Write(value);
+        consoleWriter.Write(value);
         _column += value?.Length ?? 0;
     }
 
     public void Write(char value)
     {
-        _consoleWriter.Write(value);
+        consoleWriter.Write(value);
         _column++;
     }
 
     public void Write(ConsoleColor foregroundColor, string? value)
     {
-        using (_consoleWriter.Console.WithForegroundColor(foregroundColor))
+        using (consoleWriter.Console.WithForegroundColor(foregroundColor))
             Write(value);
     }
 
     public void Write(ConsoleColor foregroundColor, char value)
     {
-        using (_consoleWriter.Console.WithForegroundColor(foregroundColor))
+        using (consoleWriter.Console.WithForegroundColor(foregroundColor))
             Write(value);
     }
 
     public void Write(ConsoleColor foregroundColor, ConsoleColor backgroundColor, string? value)
     {
-        using (_consoleWriter.Console.WithColors(foregroundColor, backgroundColor))
+        using (consoleWriter.Console.WithColors(foregroundColor, backgroundColor))
             Write(value);
     }
 
     public void WriteLine()
     {
-        _consoleWriter.WriteLine();
+        consoleWriter.WriteLine();
         _column = 0;
         _row++;
     }

CliFx/Formatting/ExceptionConsoleFormatter.cs

@@ -7,11 +7,9 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Formatting;
 
-internal class ExceptionConsoleFormatter : ConsoleFormatter
+internal class ExceptionConsoleFormatter(ConsoleWriter consoleWriter)
+    : ConsoleFormatter(consoleWriter)
 {
-    public ExceptionConsoleFormatter(ConsoleWriter consoleWriter)
-        : base(consoleWriter) { }
-
     private void WriteStackFrame(StackFrame stackFrame, int indentLevel)
     {
         WriteHorizontalMargin(2 + 4 * indentLevel);
@@ -124,4 +122,7 @@ internal static class ExceptionConsoleFormatterExtensions
 {
     public static void WriteException(this ConsoleWriter consoleWriter, Exception exception) =>
         new ExceptionConsoleFormatter(consoleWriter).WriteException(exception);
+
+    public static void WriteException(this IConsole console, Exception exception) =>
+        console.Error.WriteException(exception);
 }

CliFx/Formatting/HelpConsoleFormatter.cs

@@ -9,16 +9,9 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Formatting;
 
-internal class HelpConsoleFormatter : ConsoleFormatter
+internal class HelpConsoleFormatter(ConsoleWriter consoleWriter, HelpContext context)
+    : ConsoleFormatter(consoleWriter)
 {
-    private readonly HelpContext _context;
-
-    public HelpConsoleFormatter(ConsoleWriter consoleWriter, HelpContext context)
-        : base(consoleWriter)
-    {
-        _context = context;
-    }
-
     private void WriteHeader(string text)
     {
         Write(ConsoleColor.White, text.ToUpperInvariant());
@@ -27,13 +20,13 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
     private void WriteCommandInvocation()
     {
-        Write(_context.ApplicationMetadata.ExecutableName);
+        Write(context.ApplicationMetadata.ExecutableName);
 
         // Command name
-        if (!string.IsNullOrWhiteSpace(_context.CommandSchema.Name))
+        if (!string.IsNullOrWhiteSpace(context.CommandSchema.Name))
         {
             Write(' ');
-            Write(ConsoleColor.Cyan, _context.CommandSchema.Name);
+            Write(ConsoleColor.Cyan, context.CommandSchema.Name);
         }
     }
 
@@ -43,16 +36,16 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             WriteVerticalMargin();
 
         // Title and version
-        Write(ConsoleColor.White, _context.ApplicationMetadata.Title);
+        Write(ConsoleColor.White, context.ApplicationMetadata.Title);
         Write(' ');
-        Write(ConsoleColor.Yellow, _context.ApplicationMetadata.Version);
+        Write(ConsoleColor.Yellow, context.ApplicationMetadata.Version);
         WriteLine();
 
         // Description
-        if (!string.IsNullOrWhiteSpace(_context.ApplicationMetadata.Description))
+        if (!string.IsNullOrWhiteSpace(context.ApplicationMetadata.Description))
         {
             WriteHorizontalMargin();
-            Write(_context.ApplicationMetadata.Description);
+            Write(context.ApplicationMetadata.Description);
             WriteLine();
         }
     }
@@ -72,7 +65,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             Write(' ');
 
             // Parameters
-            foreach (var parameter in _context.CommandSchema.Parameters.OrderBy(p => p.Order))
+            foreach (var parameter in context.CommandSchema.Parameters.OrderBy(p => p.Order))
             {
                 Write(
                     ConsoleColor.DarkCyan,
@@ -82,7 +75,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             }
 
             // Required options
-            foreach (var option in _context.CommandSchema.Options.Where(o => o.IsRequired))
+            foreach (var option in context.CommandSchema.Options.Where(o => o.IsRequired))
             {
                 Write(
                     ConsoleColor.Yellow,
@@ -97,7 +90,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             }
 
             // Placeholder for non-required options
-            if (_context.CommandSchema.Options.Any(o => !o.IsRequired))
+            if (context.CommandSchema.Options.Any(o => !o.IsRequired))
             {
                 Write(ConsoleColor.Yellow, "[options]");
             }
@@ -106,9 +99,9 @@ internal class HelpConsoleFormatter : ConsoleFormatter
         }
 
         // Child command usage
-        var childCommandSchemas = _context
+        var childCommandSchemas = context.ApplicationSchema.GetChildCommands(
-            .ApplicationSchema
+            context.CommandSchema.Name
-            .GetChildCommands(_context.CommandSchema.Name);
+        );
 
         if (childCommandSchemas.Any())
         {
@@ -130,7 +123,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
     private void WriteCommandDescription()
     {
-        if (string.IsNullOrWhiteSpace(_context.CommandSchema.Description))
+        if (string.IsNullOrWhiteSpace(context.CommandSchema.Description))
             return;
 
         if (!IsEmpty)
@@ -140,13 +133,13 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
         WriteHorizontalMargin();
 
-        Write(_context.CommandSchema.Description);
+        Write(context.CommandSchema.Description);
         WriteLine();
     }
 
     private void WriteCommandParameters()
     {
-        if (!_context.CommandSchema.Parameters.Any())
+        if (!context.CommandSchema.Parameters.Any())
             return;
 
         if (!IsEmpty)
@@ -154,7 +147,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
         WriteHeader("Parameters");
 
-        foreach (var parameterSchema in _context.CommandSchema.Parameters.OrderBy(p => p.Order))
+        foreach (var parameterSchema in context.CommandSchema.Parameters.OrderBy(p => p.Order))
         {
             if (parameterSchema.IsRequired)
             {
@@ -224,7 +217,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
         WriteHeader("Options");
 
         foreach (
-            var optionSchema in _context.CommandSchema.Options.OrderByDescending(o => o.IsRequired)
+            var optionSchema in context.CommandSchema.Options.OrderByDescending(o => o.IsRequired)
         )
         {
             if (optionSchema.IsRequired)
@@ -314,7 +307,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
     private void WriteDefaultValue(IMemberSchema schema)
     {
-        var defaultValue = _context.CommandDefaultValues.GetValueOrDefault(schema);
+        var defaultValue = context.CommandDefaultValues.GetValueOrDefault(schema);
         if (defaultValue is not null)
         {
             // Non-Scalar
@@ -365,9 +358,8 @@ internal class HelpConsoleFormatter : ConsoleFormatter
 
     private void WriteCommandChildren()
     {
-        var childCommandSchemas = _context
+        var childCommandSchemas = context
-            .ApplicationSchema
+            .ApplicationSchema.GetChildCommands(context.CommandSchema.Name)
-            .GetChildCommands(_context.CommandSchema.Name)
             .OrderBy(a => a.Name, StringComparer.Ordinal)
             .ToArray();
 
@@ -386,7 +378,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             Write(
                 ConsoleColor.Cyan,
                 // Relative to current command
-                childCommandSchema.Name?.Substring(_context.CommandSchema.Name?.Length ?? 0).Trim()
+                childCommandSchema.Name?.Substring(context.CommandSchema.Name?.Length ?? 0).Trim()
             );
 
             WriteColumnMargin();
@@ -399,9 +391,8 @@ internal class HelpConsoleFormatter : ConsoleFormatter
             }
 
             // Child commands of child command
-            var grandChildCommandSchemas = _context
+            var grandChildCommandSchemas = context
-                .ApplicationSchema
+                .ApplicationSchema.GetChildCommands(childCommandSchema.Name)
-                .GetChildCommands(childCommandSchema.Name)
                 .OrderBy(c => c.Name, StringComparer.Ordinal)
                 .ToArray();
 
@@ -425,8 +416,7 @@ internal class HelpConsoleFormatter : ConsoleFormatter
                         ConsoleColor.Cyan,
                         // Relative to current command (not the parent)
                         grandChildCommandSchema
-                            .Name
+                            .Name?.Substring(context.CommandSchema.Name?.Length ?? 0)
-                            ?.Substring(_context.CommandSchema.Name?.Length ?? 0)
                             .Trim()
                     );
                 }
@@ -465,4 +455,7 @@ internal static class HelpConsoleFormatterExtensions
 {
     public static void WriteHelpText(this ConsoleWriter consoleWriter, HelpContext context) =>
         new HelpConsoleFormatter(consoleWriter, context).WriteHelpText();
+
+    public static void WriteHelpText(this IConsole console, HelpContext context) =>
+        console.Output.WriteHelpText(context);
 }

CliFx/Formatting/HelpContext.cs

@@ -3,26 +3,19 @@ using CliFx.Schema;
 
 namespace CliFx.Formatting;
 
-internal class HelpContext
+internal class HelpContext(
-{
-    public ApplicationMetadata ApplicationMetadata { get; }
-
-    public ApplicationSchema ApplicationSchema { get; }
-
-    public CommandSchema CommandSchema { get; }
-
-    public IReadOnlyDictionary<IMemberSchema, object?> CommandDefaultValues { get; }
-
-    public HelpContext(
     ApplicationMetadata applicationMetadata,
     ApplicationSchema applicationSchema,
     CommandSchema commandSchema,
     IReadOnlyDictionary<IMemberSchema, object?> commandDefaultValues
-    )
+)
-    {
+{
-        ApplicationMetadata = applicationMetadata;
+    public ApplicationMetadata ApplicationMetadata { get; } = applicationMetadata;
-        ApplicationSchema = applicationSchema;
+
-        CommandSchema = commandSchema;
+    public ApplicationSchema ApplicationSchema { get; } = applicationSchema;
-        CommandDefaultValues = commandDefaultValues;
+
-    }
+    public CommandSchema CommandSchema { get; } = commandSchema;
+
+    public IReadOnlyDictionary<IMemberSchema, object?> CommandDefaultValues { get; } =
+        commandDefaultValues;
 }

CliFx/Infrastructure/ConsoleReader.cs

@@ -11,28 +11,20 @@ namespace CliFx.Infrastructure;
 /// </summary>
 // Both the underlying stream AND the stream reader must be synchronized!
 // https://github.com/Tyrrrz/CliFx/issues/123
-public partial class ConsoleReader : StreamReader
+public class ConsoleReader(IConsole console, Stream stream, Encoding encoding)
+    : StreamReader(Stream.Synchronized(stream), encoding, false, 4096)
 {
-    /// <summary>
-    /// Console that owns this stream.
-    /// </summary>
-    public IConsole Console { get; }
-
-    /// <summary>
-    /// Initializes an instance of <see cref="ConsoleReader" />.
-    /// </summary>
-    public ConsoleReader(IConsole console, Stream stream, Encoding encoding)
-        : base(stream, encoding, false, 4096)
-    {
-        Console = console;
-    }
-
     /// <summary>
     /// Initializes an instance of <see cref="ConsoleReader" />.
     /// </summary>
     public ConsoleReader(IConsole console, Stream stream)
         : this(console, stream, System.Console.InputEncoding) { }
 
+    /// <summary>
+    /// Console that owns this stream.
+    /// </summary>
+    public IConsole Console { get; } = console;
+
     // The following overrides are required to establish thread-safe behavior
     // in methods deriving from StreamReader.
 
@@ -94,9 +86,3 @@ public partial class ConsoleReader : StreamReader
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
     protected override void Dispose(bool disposing) => base.Dispose(disposing);
 }
-
-public partial class ConsoleReader
-{
-    internal static ConsoleReader Create(IConsole console, Stream stream) =>
-        new(console, Stream.Synchronized(stream));
-}

CliFx/Infrastructure/ConsoleWriter.cs

@@ -12,20 +12,16 @@ namespace CliFx.Infrastructure;
 /// </summary>
 // Both the underlying stream AND the stream writer must be synchronized!
 // https://github.com/Tyrrrz/CliFx/issues/123
-public partial class ConsoleWriter : StreamWriter
+public class ConsoleWriter : StreamWriter
 {
-    /// <summary>
-    /// Console that owns this stream.
-    /// </summary>
-    public IConsole Console { get; }
-
     /// <summary>
     /// Initializes an instance of <see cref="ConsoleWriter" />.
     /// </summary>
     public ConsoleWriter(IConsole console, Stream stream, Encoding encoding)
-        : base(stream, encoding.WithoutPreamble(), 256)
+        : base(Stream.Synchronized(stream), encoding.WithoutPreamble(), 256)
     {
         Console = console;
+        AutoFlush = true;
     }
 
     /// <summary>
@@ -34,6 +30,11 @@ public partial class ConsoleWriter : StreamWriter
     public ConsoleWriter(IConsole console, Stream stream)
         : this(console, stream, System.Console.OutputEncoding) { }
 
+    /// <summary>
+    /// Console that owns this stream.
+    /// </summary>
+    public IConsole Console { get; }
+
     // The following overrides are required to establish thread-safe behavior
     // in methods deriving from StreamWriter.
 
@@ -44,7 +45,7 @@ public partial class ConsoleWriter : StreamWriter
 
     /// <inheritdoc />
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
-    public override void Write(char[] buffer) => base.Write(buffer);
+    public override void Write(char[]? buffer) => base.Write(buffer);
 
     /// <inheritdoc />
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
@@ -146,7 +147,7 @@ public partial class ConsoleWriter : StreamWriter
 
     /// <inheritdoc />
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
-    public override void WriteLine(char[] buffer) => base.WriteLine(buffer);
+    public override void WriteLine(char[]? buffer) => base.WriteLine(buffer);
 
     /// <inheritdoc />
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
@@ -268,9 +269,3 @@ public partial class ConsoleWriter : StreamWriter
     [ExcludeFromCodeCoverage, MethodImpl(MethodImplOptions.Synchronized)]
     protected override void Dispose(bool disposing) => base.Dispose(disposing);
 }
-
-public partial class ConsoleWriter
-{
-    internal static ConsoleWriter Create(IConsole console, Stream stream) =>
-        new(console, Stream.Synchronized(stream)) { AutoFlush = true };
-}

CliFx/Infrastructure/DefaultTypeActivator.cs

@@ -14,14 +14,20 @@ public class DefaultTypeActivator : ITypeActivator
     {
         try
         {
-            return Activator.CreateInstance(type);
+            return Activator.CreateInstance(type)
+                ?? throw CliFxException.InternalError(
+                    $"""
+                    Failed to create an instance of type `{type.FullName}`, received <null> instead.
+                    This may be caused by the type's constructor being trimmed away.
+                    """
+                );
         }
         // Only catch MemberAccessException because the constructor can throw for its own reasons too
         catch (MemberAccessException ex)
         {
             throw CliFxException.InternalError(
                 $"""
-                Failed to create an instance of type `{type.FullName}`, could not access the constructor.
+                Failed to create an instance of type `{type.FullName}` because an appropriate constructor is not available.
                 Default type activator is only capable of instantiating a type if it has a public parameterless constructor.
                 To fix this, either add a parameterless constructor to the type or configure a custom activator for the application.
                 """,

CliFx/Infrastructure/DelegateTypeActivator.cs

@@ -6,32 +6,16 @@ namespace CliFx.Infrastructure;
 /// <summary>
 /// Implementation of <see cref="ITypeActivator" /> that instantiates an object by using a predefined delegate.
 /// </summary>
-public class DelegateTypeActivator : ITypeActivator
+public class DelegateTypeActivator(Func<Type, object> createInstance) : ITypeActivator
 {
-    private readonly Func<Type, object> _createInstance;
-
-    /// <summary>
-    /// Initializes an instance of <see cref="DelegateTypeActivator" />.
-    /// </summary>
-    public DelegateTypeActivator(Func<Type, object> createInstance) =>
-        _createInstance = createInstance;
-
     /// <inheritdoc />
-    public object CreateInstance(Type type)
+    public object CreateInstance(Type type) =>
-    {
+        createInstance(type)
-        var instance = _createInstance(type);
+        ?? throw CliFxException.InternalError(
-
-        if (instance is null)
-        {
-            throw CliFxException.InternalError(
             $"""
             Failed to create an instance of type `{type.FullName}`, received <null> instead.
             To fix this, ensure that the provided type activator is configured correctly, as it's not expected to return <null>.
             If you are relying on a dependency container, this error may indicate that the specified type has not been registered.
             """
         );
-        }
-
-        return instance;
-    }
 }

CliFx/Infrastructure/FakeConsole.cs

@@ -6,15 +6,24 @@ using System.Threading;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="IConsole" /> that uses the provided fake
+/// Implementation of <see cref="IConsole" /> that uses the provided fake standard input, output, and error streams.
-/// standard input, output, and error streams.
+/// Use this implementation in tests to verify how a command interacts with the console.
-/// Use this implementation in tests to verify command interactions with the console.
 /// </summary>
 public class FakeConsole : IConsole, IDisposable
 {
     private readonly CancellationTokenSource _cancellationTokenSource = new();
     private readonly ConcurrentQueue<ConsoleKeyInfo> _keys = new();
 
+    /// <summary>
+    /// Initializes an instance of <see cref="FakeConsole" />.
+    /// </summary>
+    public FakeConsole(Stream? input = null, Stream? output = null, Stream? error = null)
+    {
+        Input = new ConsoleReader(this, input ?? Stream.Null);
+        Output = new ConsoleWriter(this, output ?? Stream.Null);
+        Error = new ConsoleWriter(this, error ?? Stream.Null);
+    }
+
     /// <inheritdoc />
     public ConsoleReader Input { get; }
 
@@ -52,14 +61,9 @@ public class FakeConsole : IConsole, IDisposable
     public int CursorTop { get; set; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="FakeConsole" />.
+    /// Enqueues a simulated key press, which can then be read by calling <see cref="ReadKey" />.
     /// </summary>
-    public FakeConsole(Stream? input = null, Stream? output = null, Stream? error = null)
+    public void EnqueueKey(ConsoleKeyInfo key) => _keys.Enqueue(key);
-    {
-        Input = ConsoleReader.Create(this, input ?? Stream.Null);
-        Output = ConsoleWriter.Create(this, output ?? Stream.Null);
-        Error = ConsoleWriter.Create(this, error ?? Stream.Null);
-    }
 
     /// <inheritdoc />
     public ConsoleKeyInfo ReadKey(bool intercept = false) =>
@@ -70,11 +74,6 @@ public class FakeConsole : IConsole, IDisposable
                     + $"Use the `{nameof(EnqueueKey)}(...)` method to simulate a key press."
             );
 
-    /// <summary>
-    /// Enqueues a simulated key press, which can then be read by calling <see cref="ReadKey" />.
-    /// </summary>
-    public void EnqueueKey(ConsoleKeyInfo key) => _keys.Enqueue(key);
-
     /// <inheritdoc />
     public void ResetColor()
     {
@@ -85,11 +84,8 @@ public class FakeConsole : IConsole, IDisposable
     /// <inheritdoc />
     public void Clear() { }
 
-    /// <inheritdoc />
-    public CancellationToken RegisterCancellationHandler() => _cancellationTokenSource.Token;
-
     /// <summary>
-    /// Sends a cancellation signal to the currently executing command.
+    /// Simulates a cancellation request.
     /// </summary>
     /// <remarks>
     /// If the command is not cancellation-aware (i.e. it doesn't call <see cref="IConsole.RegisterCancellationHandler" />),
@@ -108,6 +104,9 @@ public class FakeConsole : IConsole, IDisposable
         }
     }
 
+    /// <inheritdoc />
+    public CancellationToken RegisterCancellationHandler() => _cancellationTokenSource.Token;
+
     /// <inheritdoc />
     public virtual void Dispose() => _cancellationTokenSource.Dispose();
 }

CliFx/Infrastructure/FakeInMemoryConsole.cs

@@ -3,9 +3,9 @@
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="IConsole" /> that uses fake
+/// Implementation of <see cref="IConsole" /> that uses fake standard input, output, and error streams
-/// standard input, output, and error streams backed by in-memory stores.
+/// backed by in-memory stores.
-/// Use this implementation in tests to verify command interactions with the console.
+/// Use this implementation in tests to verify how a command interacts with the console.
 /// </summary>
 public class FakeInMemoryConsole : FakeConsole
 {

CliFx/Infrastructure/IConsole.cs

@@ -5,47 +5,47 @@ using CliFx.Utils;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Abstraction for the console layer.
+/// Abstraction for interacting with the console layer.
 /// </summary>
 public interface IConsole
 {
     /// <summary>
-    /// Input stream (stdin).
+    /// Console's standard input stream.
     /// </summary>
     ConsoleReader Input { get; }
 
     /// <summary>
-    /// Gets a value that indicates whether input has been redirected from the standard input stream.
+    /// Whether the input stream has been redirected.
     /// </summary>
     bool IsInputRedirected { get; }
 
     /// <summary>
-    /// Output stream (stdout).
+    /// Console's standard output stream.
     /// </summary>
     ConsoleWriter Output { get; }
 
     /// <summary>
-    /// Gets a value that indicates whether output has been redirected from the standard output stream.
+    /// Whether the output stream has been redirected.
     /// </summary>
     bool IsOutputRedirected { get; }
 
     /// <summary>
-    /// Error stream (stderr).
+    /// Console's standard error stream.
     /// </summary>
     ConsoleWriter Error { get; }
 
     /// <summary>
-    /// Gets a value that indicates whether error output has been redirected from the standard error stream.
+    /// Whether the error stream has been redirected.
     /// </summary>
     bool IsErrorRedirected { get; }
 
     /// <summary>
-    /// Gets or sets the foreground color of the console
+    /// Gets or sets the current foreground color of the console.
     /// </summary>
     ConsoleColor ForegroundColor { get; set; }
 
     /// <summary>
-    /// Gets or sets the background color of the console.
+    /// Gets or sets the current background color of the console.
     /// </summary>
     ConsoleColor BackgroundColor { get; set; }
 
@@ -108,6 +108,43 @@ public interface IConsole
 /// </summary>
 public static class ConsoleExtensions
 {
+    /// <summary>
+    /// Writes a string to the console's output stream.
+    /// </summary>
+    public static void Write(this IConsole console, string? value) => console.Output.Write(value);
+
+    /// <summary>
+    /// Writes an object to the console's output stream.
+    /// </summary>
+    public static void Write(this IConsole console, object? value) => console.Output.Write(value);
+
+    /// <summary>
+    /// Writes an empty line to the console's output stream.
+    /// </summary>
+    public static void WriteLine(this IConsole console) => console.Output.WriteLine();
+
+    /// <summary>
+    /// Writes a string to the console's output stream, followed by a line terminator.
+    /// </summary>
+    public static void WriteLine(this IConsole console, string? value) =>
+        console.Output.WriteLine(value);
+
+    /// <summary>
+    /// Writes an object to the console's output stream, followed by a line terminator.
+    /// </summary>
+    public static void WriteLine(this IConsole console, object? value) =>
+        console.Output.WriteLine(value);
+
+    /// <summary>
+    /// Reads a single character from the console's input stream.
+    /// </summary>
+    public static int Read(this IConsole console) => console.Input.Read();
+
+    /// <summary>
+    /// Reads a line from the console's input stream.
+    /// </summary>
+    public static string? ReadLine(this IConsole console) => console.Input.ReadLine();
+
     /// <summary>
     /// Sets the specified foreground color and returns an <see cref="IDisposable" />
     /// that will reset the color back to its previous value upon disposal.

CliFx/Infrastructure/SystemConsole.cs

@@ -10,6 +10,16 @@ public class SystemConsole : IConsole, IDisposable
 {
     private CancellationTokenSource? _cancellationTokenSource;
 
+    /// <summary>
+    /// Initializes an instance of <see cref="SystemConsole" />.
+    /// </summary>
+    public SystemConsole()
+    {
+        Input = new ConsoleReader(this, Console.OpenStandardInput());
+        Output = new ConsoleWriter(this, Console.OpenStandardOutput());
+        Error = new ConsoleWriter(this, Console.OpenStandardError());
+    }
+
     /// <inheritdoc />
     public ConsoleReader Input { get; }
 
@@ -70,16 +80,6 @@ public class SystemConsole : IConsole, IDisposable
         set => Console.CursorTop = value;
     }
 
-    /// <summary>
-    /// Initializes an instance of <see cref="SystemConsole" />.
-    /// </summary>
-    public SystemConsole()
-    {
-        Input = ConsoleReader.Create(this, Console.OpenStandardInput());
-        Output = ConsoleWriter.Create(this, Console.OpenStandardOutput());
-        Error = ConsoleWriter.Create(this, Console.OpenStandardError());
-    }
-
     /// <inheritdoc />
     public ConsoleKeyInfo ReadKey(bool intercept = false) => Console.ReadKey(intercept);
 

CliFx/Input/CommandInput.cs

@@ -5,17 +5,24 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Input;
 
-internal partial class CommandInput
+internal partial class CommandInput(
+    string? commandName,
+    IReadOnlyList<DirectiveInput> directives,
+    IReadOnlyList<ParameterInput> parameters,
+    IReadOnlyList<OptionInput> options,
+    IReadOnlyList<EnvironmentVariableInput> environmentVariables
+)
 {
-    public string? CommandName { get; }
+    public string? CommandName { get; } = commandName;
 
-    public IReadOnlyList<DirectiveInput> Directives { get; }
+    public IReadOnlyList<DirectiveInput> Directives { get; } = directives;
 
-    public IReadOnlyList<ParameterInput> Parameters { get; }
+    public IReadOnlyList<ParameterInput> Parameters { get; } = parameters;
 
-    public IReadOnlyList<OptionInput> Options { get; }
+    public IReadOnlyList<OptionInput> Options { get; } = options;
 
-    public IReadOnlyList<EnvironmentVariableInput> EnvironmentVariables { get; }
+    public IReadOnlyList<EnvironmentVariableInput> EnvironmentVariables { get; } =
+        environmentVariables;
 
     public bool HasArguments =>
         !string.IsNullOrWhiteSpace(CommandName)
@@ -30,21 +37,6 @@ internal partial class CommandInput
     public bool IsHelpOptionSpecified => Options.Any(o => o.IsHelpOption);
 
     public bool IsVersionOptionSpecified => Options.Any(o => o.IsVersionOption);
-
-    public CommandInput(
-        string? commandName,
-        IReadOnlyList<DirectiveInput> directives,
-        IReadOnlyList<ParameterInput> parameters,
-        IReadOnlyList<OptionInput> options,
-        IReadOnlyList<EnvironmentVariableInput> environmentVariables
-    )
-    {
-        CommandName = commandName;
-        Directives = directives;
-        Parameters = parameters;
-        Options = options;
-        EnvironmentVariables = environmentVariables;
-    }
 }
 
 internal partial class CommandInput
@@ -168,7 +160,7 @@ internal partial class CommandInput
                     result.Add(new OptionInput(lastOptionIdentifier, lastOptionValues));
 
                 lastOptionIdentifier = argument[2..];
-                lastOptionValues = new List<string>();
+                lastOptionValues = [];
             }
             // Short name
             else if (argument.StartsWith('-') && argument.Length > 1 && char.IsLetter(argument[1]))
@@ -180,7 +172,7 @@ internal partial class CommandInput
                         result.Add(new OptionInput(lastOptionIdentifier, lastOptionValues));
 
                     lastOptionIdentifier = identifier.AsString();
-                    lastOptionValues = new List<string>();
+                    lastOptionValues = [];
                 }
             }
             // Value

CliFx/Input/DirectiveInput.cs

@@ -2,15 +2,13 @@
 
 namespace CliFx.Input;
 
-internal class DirectiveInput
+internal class DirectiveInput(string name)
 {
-    public string Name { get; }
+    public string Name { get; } = name;
 
     public bool IsDebugDirective =>
         string.Equals(Name, "debug", StringComparison.OrdinalIgnoreCase);
 
     public bool IsPreviewDirective =>
         string.Equals(Name, "preview", StringComparison.OrdinalIgnoreCase);
-
-    public DirectiveInput(string name) => Name = name;
 }

CliFx/Input/EnvironmentVariableInput.cs

@@ -3,17 +3,11 @@ using System.IO;
 
 namespace CliFx.Input;
 
-internal class EnvironmentVariableInput
+internal class EnvironmentVariableInput(string name, string value)
 {
-    public string Name { get; }
+    public string Name { get; } = name;
 
-    public string Value { get; }
+    public string Value { get; } = value;
-
-    public EnvironmentVariableInput(string name, string value)
-    {
-        Name = name;
-        Value = value;
-    }
 
     public IReadOnlyList<string> SplitValues() => Value.Split(Path.PathSeparator);
 }

CliFx/Input/OptionInput.cs

@@ -3,26 +3,20 @@ using CliFx.Schema;
 
 namespace CliFx.Input;
 
-internal class OptionInput
+internal class OptionInput(string identifier, IReadOnlyList<string> values)
 {
-    public string Identifier { get; }
+    public string Identifier { get; } = identifier;
 
-    public IReadOnlyList<string> Values { get; }
+    public IReadOnlyList<string> Values { get; } = values;
 
     public bool IsHelpOption => OptionSchema.HelpOption.MatchesIdentifier(Identifier);
 
     public bool IsVersionOption => OptionSchema.VersionOption.MatchesIdentifier(Identifier);
 
-    public OptionInput(string identifier, IReadOnlyList<string> values)
-    {
-        Identifier = identifier;
-        Values = values;
-    }
-
     public string GetFormattedIdentifier() =>
         Identifier switch
         {
             { Length: >= 2 } => "--" + Identifier,
-            _ => '-' + Identifier
+            _ => '-' + Identifier,
         };
 }

CliFx/Input/ParameterInput.cs

@@ -1,10 +1,8 @@
 namespace CliFx.Input;
 
-internal class ParameterInput
+internal class ParameterInput(string value)
 {
-    public string Value { get; }
+    public string Value { get; } = value;
-
-    public ParameterInput(string value) => Value = value;
 
     public string GetFormattedIdentifier() => $"<{Value}>";
 }

CliFx/Schema/ApplicationSchema.cs

@@ -5,14 +5,9 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
-internal partial class ApplicationSchema
+internal partial class ApplicationSchema(IReadOnlyList<CommandSchema> commands)
 {
-    public IReadOnlyList<CommandSchema> Commands { get; }
+    public IReadOnlyList<CommandSchema> Commands { get; } = commands;
-
-    public ApplicationSchema(IReadOnlyList<CommandSchema> commands)
-    {
-        Commands = commands;
-    }
 
     public IReadOnlyList<string> GetCommandNames() =>
         Commands.Select(c => c.Name).WhereNotNullOrWhiteSpace().ToArray();
@@ -44,9 +39,10 @@ internal partial class ApplicationSchema
                 string.IsNullOrWhiteSpace(parentCommandName)
                 ||
                 // Otherwise a command is a descendant if it starts with the same name segments
-                potentialParentCommandSchema
+                potentialParentCommandSchema.Name.StartsWith(
-                    .Name
+                    parentCommandName + ' ',
-                    .StartsWith(parentCommandName + ' ', StringComparison.OrdinalIgnoreCase);
+                    StringComparison.OrdinalIgnoreCase
+                );
 
             if (isDescendant)
                 result.Add(potentialParentCommandSchema);

CliFx/Schema/BindablePropertyDescriptor.cs

@@ -5,18 +5,14 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
-internal class BindablePropertyDescriptor : IPropertyDescriptor
+internal class BindablePropertyDescriptor(PropertyInfo property) : IPropertyDescriptor
 {
-    private readonly PropertyInfo _property;
+    public Type Type => property.PropertyType;
 
-    public Type Type => _property.PropertyType;
+    public object? GetValue(ICommand commandInstance) => property.GetValue(commandInstance);
-
-    public BindablePropertyDescriptor(PropertyInfo property) => _property = property;
-
-    public object? GetValue(ICommand commandInstance) => _property.GetValue(commandInstance);
 
     public void SetValue(ICommand commandInstance, object? value) =>
-        _property.SetValue(commandInstance, value);
+        property.SetValue(commandInstance, value);
 
     public IReadOnlyList<object?> GetValidValues()
     {

CliFx/Schema/CommandSchema.cs

@@ -8,17 +8,23 @@ using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
-internal partial class CommandSchema
+internal partial class CommandSchema(
+    Type type,
+    string? name,
+    string? description,
+    IReadOnlyList<ParameterSchema> parameters,
+    IReadOnlyList<OptionSchema> options
+)
 {
-    public Type Type { get; }
+    public Type Type { get; } = type;
 
-    public string? Name { get; }
+    public string? Name { get; } = name;
 
-    public string? Description { get; }
+    public string? Description { get; } = description;
 
-    public IReadOnlyList<ParameterSchema> Parameters { get; }
+    public IReadOnlyList<ParameterSchema> Parameters { get; } = parameters;
 
-    public IReadOnlyList<OptionSchema> Options { get; }
+    public IReadOnlyList<OptionSchema> Options { get; } = options;
 
     public bool IsDefault => string.IsNullOrWhiteSpace(Name);
 
@@ -26,21 +32,6 @@ internal partial class CommandSchema
 
     public bool IsVersionOptionAvailable => Options.Contains(OptionSchema.VersionOption);
 
-    public CommandSchema(
-        Type type,
-        string? name,
-        string? description,
-        IReadOnlyList<ParameterSchema> parameters,
-        IReadOnlyList<OptionSchema> options
-    )
-    {
-        Type = type;
-        Name = name;
-        Description = description;
-        Parameters = parameters;
-        Options = options;
-    }
-
     public bool MatchesName(string? name) =>
         !string.IsNullOrWhiteSpace(Name)
             ? string.Equals(name, Name, StringComparison.OrdinalIgnoreCase)
@@ -95,10 +86,14 @@ internal partial class CommandSchema
                 type.GetInterfaces()
                     // Only interfaces implementing ICommand for explicitness
                     .Where(i => i != typeof(ICommand) && i.IsAssignableTo(typeof(ICommand)))
-                    .SelectMany(
+                    .SelectMany(i =>
-                        i =>
                         i.GetProperties()
-                                .Where(p => !p.GetMethod.IsAbstract && !p.SetMethod.IsAbstract)
+                            .Where(p =>
+                                p.GetMethod is not null
+                                && !p.GetMethod.IsAbstract
+                                && p.SetMethod is not null
+                                && !p.SetMethod.IsAbstract
+                            )
                     )
             )
             .ToArray();

CliFx/Schema/IMemberSchema.cs

@@ -21,6 +21,6 @@ internal static class MemberSchemaExtensions
         {
             ParameterSchema => "Parameter",
             OptionSchema => "Option",
-            _ => throw new ArgumentOutOfRangeException(nameof(memberSchema))
+            _ => throw new ArgumentOutOfRangeException(nameof(memberSchema)),
         };
 }