Update version

Closes #132

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,8 @@
 blank_issues_enabled: false
 contact_links:
+  - name: ⚠ Feature request
+    url: https://github.com/Tyrrrz/.github/blob/master/docs/project-status.md
+    about: Sorry, but this project is in maintenance mode and no longer accepts new feature requests.
   - name: 💬 Discord server
     url: https://discord.gg/2SUWKFnHSm
     about: Chat with the project community.

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -1,22 +0,0 @@
-name: ✨ Feature request
-description: Request a new feature.
-labels: [enhancement]
-
-body:
-- type: markdown
-  attributes:
-    value: |
-      🧐 **Guidelines:**
-
-      - Search through [existing issues](https://github.com/Tyrrrz/CliFx/issues?q=is%3Aissue) first to ensure that this feature has not been requested before.
-      - Write a descriptive title for your issue. Avoid generic or vague titles such as "Some suggestions" or "Ideas for improvement".
-      - Keep your issue focused on one single problem. If you have multiple feature requests, please create separate issues for each of them.
-      - Provide as much context as possible in the details section. Include screenshots, screen recordings, links, references, or anything else you may consider relevant.
-      - If you want to ask a question instead of requesting a feature, please use [discussions](https://github.com/Tyrrrz/CliFx/discussions/new) instead.
-
-- type: textarea
-  attributes:
-    label: Details
-    description: Clear and thorough explanation of the feature you have in mind.
-  validations:
-    required: true

.github/workflows/main.yml

@@ -6,7 +6,7 @@ jobs:
   main:
     uses: Tyrrrz/.github/.github/workflows/nuget.yml@master
     with:
-      dotnet-version: 6.0.x
+      dotnet-version: 7.0.x
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
       NUGET_TOKEN: ${{ secrets.NUGET_TOKEN }}

Changelog.md

@@ -1,3 +1,7 @@
+### 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.

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

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -9,14 +9,14 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies" Version="1.2.4" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.1" />
-    <PackageReference Include="GitHubActionsTestLogger" Version="2.0.0" PrivateAssets="all" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="2.0.1" PrivateAssets="all" />
-    <PackageReference Include="FluentAssertions" Version="6.7.0" />
+    <PackageReference Include="FluentAssertions" Version="6.8.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.2.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="all" />
-    <PackageReference Include="coverlet.collector" Version="3.1.2" PrivateAssets="all" />
+    <PackageReference Include="coverlet.collector" Version="3.2.0" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Analyzers.Tests/CommandMustBeAnnotatedAnalyzerSpecs.cs

@@ -13,11 +13,13 @@ public class CommandMustBeAnnotatedAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyCommand : ICommand
+            """
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            {
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -28,12 +30,14 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public abstract class MyCommand : ICommand
+            [Command]
-{
+            public abstract class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            {
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -44,11 +48,13 @@ public abstract class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public abstract class MyCommand : ICommand
+            """
-{
+            public abstract class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            {
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -59,11 +65,13 @@ public abstract class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class Foo
+            """
-{
+            public class Foo
-    public int Bar { get; set; } = 5;
+            {
-}";
+                public int Bar { get; set; } = 5;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/CommandMustImplementInterfaceAnalyzerSpecs.cs

@@ -13,12 +13,14 @@ public class CommandMustImplementInterfaceAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand
+            [Command]
-{
+            public class MyCommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            {
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -29,12 +31,14 @@ public class MyCommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            {
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -45,11 +49,13 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class Foo
+            """
-{
+            public class Foo
-    public int Bar { get; set; } = 5;
+            {
-}";
+                public int Bar { get; set; } = 5;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustBeInsideCommandAnalyzerSpecs.cs

@@ -13,12 +13,14 @@ public class OptionMustBeInsideCommandAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyClass
+            """
-{
+            public class MyClass
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-}";
+                public string Foo { get; set; }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -29,15 +31,17 @@ public class MyClass
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}";
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -48,12 +52,14 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public abstract class MyCommand
+            """
-{
+            public abstract class MyCommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-}";
+                public string Foo { get; set; }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -64,14 +70,16 @@ public abstract class MyCommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}";
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustBeRequiredIfPropertyRequiredAnalyzerSpecs.cs

@@ -0,0 +1,114 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests;
+
+public class OptionMustBeRequiredIfPropertyRequiredAnalyzerSpecs
+{
+    private static DiagnosticAnalyzer Analyzer { get; } = new OptionMustBeRequiredIfPropertyRequiredAnalyzer();
+
+    [Fact]
+    public void Analyzer_reports_an_error_if_a_non_required_option_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = false)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().ProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_option_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = true)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_non_required_option_is_bound_to_a_non_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = false)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_option_is_bound_to_a_non_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = true)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_an_option()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+}

CliFx.Analyzers.Tests/OptionMustHaveNameOrShortNameAnalyzerSpecs.cs

@@ -13,15 +13,17 @@ public class OptionMustHaveNameOrShortNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(null)]
+            {
-    public string Foo { get; set; }
+                [CommandOption(null)]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -32,15 +34,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -51,15 +55,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -70,14 +76,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveUniqueNameAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class OptionMustHaveUniqueNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    [CommandOption(""foo"")]
+            
-    public string Bar { get; set; }
+                [CommandOption("foo")]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    [CommandOption(""bar"")]
+            
-    public string Bar { get; set; }
+                [CommandOption("bar")]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,15 +61,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -76,14 +82,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveUniqueShortNameAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class OptionMustHaveUniqueShortNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    [CommandOption('f')]
+            
-    public string Bar { get; set; }
+                [CommandOption('f')]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    [CommandOption('b')]
+            
-    public string Bar { get; set; }
+                [CommandOption('b')]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,18 +61,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    [CommandOption('F')]
+            
-    public string Bar { get; set; }
+                [CommandOption('F')]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -79,15 +85,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -98,14 +106,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveValidConverterAnalyzerSpecs.cs

@@ -13,20 +13,22 @@ public class OptionMustHaveValidConverterAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter
+            """
-{
+            public class MyConverter
-    public string Convert(string rawValue) => rawValue;
+            {
-}
+                public string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -37,20 +39,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<int>
+            """
-{
+            public class MyConverter : BindingConverter<int>
-    public override int Convert(string rawValue) => 42;
+            {
-}
+                public override int Convert(string rawValue) => 42;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -61,20 +65,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<string>
+            """
-{
+            public class MyConverter : BindingConverter<string>
-    public override string Convert(string rawValue) => rawValue;
+            {
-}
+                public override string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -85,20 +91,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<int>
+            """
-{
+            public class MyConverter : BindingConverter<int>
-    public override int Convert(string rawValue) => 42;
+            {
-}
+                public override int Convert(string rawValue) => 42;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public int? Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public int? Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -109,20 +117,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<string>
+            """
-{
+            public class MyConverter : BindingConverter<string>
-    public override string Convert(string rawValue) => rawValue;
+            {
-}
+                public override string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public IReadOnlyList<string> Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public IReadOnlyList<string> Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -133,15 +143,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -152,14 +164,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveValidNameAnalyzerSpecs.cs

@@ -13,15 +13,17 @@ public class OptionMustHaveValidNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""f"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("f")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -32,15 +34,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""1foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("1foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -51,15 +55,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -70,15 +76,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -89,14 +97,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveValidShortNameAnalyzerSpecs.cs

@@ -13,15 +13,17 @@ public class OptionMustHaveValidShortNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('1')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('1')]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -32,15 +34,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption('f')]
+            {
-    public string Foo { get; set; }
+                [CommandOption('f')]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -51,15 +55,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -70,14 +76,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/OptionMustHaveValidValidatorsAnalyzerSpecs.cs

@@ -13,20 +13,22 @@ public class OptionMustHaveValidValidatorsAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator
+            """
-{
+            public class MyValidator
-    public void Validate(string value) {}
+            {
-}
+                public void Validate(string value) {}
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -37,20 +39,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator : BindingValidator<int>
+            """
-{
+            public class MyValidator : BindingValidator<int>
-    public override BindingValidationError Validate(int value) => Ok();
+            {
-}
+                public override BindingValidationError Validate(int value) => Ok();
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -61,20 +65,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator : BindingValidator<string>
+            """
-{
+            public class MyValidator : BindingValidator<string>
-    public override BindingValidationError Validate(string value) => Ok();
+            {
-}
+                public override BindingValidationError Validate(string value) => Ok();
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo", Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -85,15 +91,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandOption("foo")]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -104,14 +112,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustBeInsideCommandAnalyzerSpecs.cs

@@ -13,12 +13,14 @@ public class ParameterMustBeInsideCommandAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyClass
+            """
-{
+            public class MyClass
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-}";
+                public string Foo { get; set; }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -29,15 +31,17 @@ public class MyClass
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -48,12 +52,14 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public abstract class MyCommand
+            """
-{
+            public abstract class MyCommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-}";
+                public string Foo { get; set; }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -64,14 +70,16 @@ public abstract class MyCommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustBeLastIfNonRequiredAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustBeLastIfNonRequiredAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Name = ""foo"", IsRequired = false)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, IsRequired = false)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, Name = ""bar"")]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Name = ""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, Name = ""bar"", IsRequired = false)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, IsRequired = false)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,18 +61,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Name = ""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, Name = ""bar"", IsRequired = true)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, IsRequired = true)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -79,14 +85,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustBeLastIfNonScalarAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustBeLastIfNonScalarAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string[] Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string[] Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string[] Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string[] Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,18 +61,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -79,14 +85,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustBeRequiredIfPropertyRequiredAnalyzerSpecs.cs

@@ -0,0 +1,114 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests;
+
+public class ParameterMustBeRequiredIfPropertyRequiredAnalyzerSpecs
+{
+    private static DiagnosticAnalyzer Analyzer { get; } = new ParameterMustBeRequiredIfPropertyRequiredAnalyzer();
+
+    [Fact]
+    public void Analyzer_reports_an_error_if_a_non_required_parameter_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = false)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().ProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_parameter_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = true)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_non_required_parameter_is_bound_to_a_non_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = false)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_parameter_is_bound_to_a_non_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = true)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_a_parameter()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+}

CliFx.Analyzers.Tests/ParameterMustBeSingleIfNonRequiredAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustBeSingleIfNonRequiredAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, IsRequired = false)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, IsRequired = false)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, IsRequired = false)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, IsRequired = false)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, IsRequired = false)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, IsRequired = false)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,18 +61,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, IsRequired = true)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, IsRequired = true)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -79,14 +85,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustBeSingleIfNonScalarAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustBeSingleIfNonScalarAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string[] Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string[] Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string[] Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string[] Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string[] Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string[] Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,18 +61,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -79,14 +85,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustHaveUniqueNameAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustHaveUniqueNameAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Name = ""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Name = "foo")]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, Name = ""foo"")]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, Name = "foo")]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Name = ""foo"")]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Name = "foo")]
-
+                public string Foo { get; set; }
-    [CommandParameter(1, Name = ""bar"")]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1, Name = "bar")]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,14 +61,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustHaveUniqueOrderAnalyzerSpecs.cs

@@ -13,18 +13,20 @@ public class ParameterMustHaveUniqueOrderAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(0)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(0)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -35,18 +37,20 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    [CommandParameter(1)]
+            
-    public string Bar { get; set; }
+                [CommandParameter(1)]
-
+                public string Bar { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -57,14 +61,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustHaveValidConverterAnalyzerSpecs.cs

@@ -13,20 +13,22 @@ public class ParameterMustHaveValidConverterAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter
+            """
-{
+            public class MyConverter
-    public string Convert(string rawValue) => rawValue;
+            {
-}
+                public string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -37,20 +39,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<int>
+            """
-{
+            public class MyConverter : BindingConverter<int>
-    public override int Convert(string rawValue) => 42;
+            {
-}
+                public override int Convert(string rawValue) => 42;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
 
         // Act & assert
@@ -62,20 +66,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<string>
+            """
-{
+            public class MyConverter : BindingConverter<string>
-    public override string Convert(string rawValue) => rawValue;
+            {
-}
+                public override string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Converter = typeof(MyConverter))]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Converter = typeof(MyConverter))]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -86,20 +92,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<int>
+            """
-{
+            public class MyConverter : BindingConverter<int>
-    public override int Convert(string rawValue) => 42;
+            {
-}
+                public override int Convert(string rawValue) => 42;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandOption(""foo"", Converter = typeof(MyConverter))]
+            {
-    public int? Foo { get; set; }
+                [CommandOption("foo", Converter = typeof(MyConverter))]
-
+                public int? Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -110,20 +118,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyConverter : BindingConverter<string>
+            """
-{
+            public class MyConverter : BindingConverter<string>
-    public override string Convert(string rawValue) => rawValue;
+            {
-}
+                public override string Convert(string rawValue) => rawValue;
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Converter = typeof(MyConverter))]
+            {
-    public IReadOnlyList<string> Foo { get; set; }
+                [CommandParameter(0, Converter = typeof(MyConverter))]
-
+                public IReadOnlyList<string> Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -134,15 +144,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -153,14 +165,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/ParameterMustHaveValidValidatorsAnalyzerSpecs.cs

@@ -13,20 +13,22 @@ public class ParameterMustHaveValidValidatorsAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator
+            """
-{
+            public class MyValidator
-    public void Validate(string value) {}
+            {
-}
+                public void Validate(string value) {}
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -37,20 +39,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator : BindingValidator<int>
+            """
-{
+            public class MyValidator : BindingValidator<int>
-    public override BindingValidationError Validate(int value) => Ok();
+            {
-}
+                public override BindingValidationError Validate(int value) => Ok();
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -61,20 +65,22 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-public class MyValidator : BindingValidator<string>
+            """
-{
+            public class MyValidator : BindingValidator<string>
-    public override BindingValidationError Validate(string value) => Ok();
+            {
-}
+                public override BindingValidationError Validate(string value) => Ok();
-
+            }
-[Command]
+            
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0, Validators = new[] {typeof(MyValidator)})]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -85,15 +91,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    [CommandParameter(0)]
+            {
-    public string Foo { get; set; }
+                [CommandParameter(0)]
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -104,14 +112,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public string Foo { get; set; }
+            {
-
+                public string Foo { get; set; }
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/SystemConsoleShouldBeAvoidedAnalyzerSpecs.cs

@@ -13,16 +13,18 @@ public class SystemConsoleShouldBeAvoidedAnalyzerSpecs
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console)
+            {
-    {
+                public ValueTask ExecuteAsync(IConsole console)
-        Console.WriteLine(""Hello world"");
+                {
-        return default;
+                    Console.WriteLine("Hello world");
-    }
+                    return default;
-}";
+                }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -33,16 +35,19 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console)
+            {
-    {
+                public ValueTask ExecuteAsync(IConsole console)
-        Console.ForegroundColor = ConsoleColor.Black;
+                {
-        return default;
+                    Console.ForegroundColor = ConsoleColor.Black;
-    }
+                    return default;
-}";
+                }
+            }
+            """;
+
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
     }
@@ -52,16 +57,18 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console)
+            {
-    {
+                public ValueTask ExecuteAsync(IConsole console)
-        Console.Error.WriteLine(""Hello world"");
+                {
-        return default;
+                    Console.Error.WriteLine("Hello world");
-    }
+                    return default;
-}";
+                }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().ProduceDiagnostics(code);
@@ -72,16 +79,18 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console)
+            {
-    {
+                public ValueTask ExecuteAsync(IConsole console)
-        console.Output.WriteLine(""Hello world"");
+                {
-        return default;
+                    console.Output.WriteLine("Hello world");
-    }
+                    return default;
-}";
+                }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -92,14 +101,16 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public void SomeOtherMethod() => Console.WriteLine(""Test"");
+            {
-
+                public void SomeOtherMethod() => Console.WriteLine("Test");
-    public ValueTask ExecuteAsync(IConsole console) => default;
+            
-}";
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);
@@ -110,15 +121,17 @@ public class MyCommand : ICommand
     {
         // Arrange
         // language=cs
-        const string code = @"
+        const string code =
-[Command]
+            """
-public class MyCommand : ICommand
+            [Command]
-{
+            public class MyCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console)
+            {
-    {
+                public ValueTask ExecuteAsync(IConsole console)
-        return default;
+                {
-    }
+                    return default;
-}";
+                }
+            }
+            """;
 
         // Act & assert
         Analyzer.Should().NotProduceDiagnostics(code);

CliFx.Analyzers.Tests/Utils/AnalyzerAssertions.cs

@@ -58,7 +58,7 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
             new[] { ast },
-            ReferenceAssemblies.Net50
+            Net70.References.All
                 .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location)),
             // DLL to avoid having to define the Main() method
             new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
@@ -72,9 +72,10 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         if (compilationErrors.Any())
         {
             throw new InvalidOperationException(
-                "Failed to compile code." +
+                $"""
-                Environment.NewLine +
+                Failed to compile code.
-                string.Join(Environment.NewLine, compilationErrors.Select(e => e.ToString()))
+                {string.Join(Environment.NewLine, compilationErrors.Select(e => e.ToString()))}
+                """
             );
         }
 

CliFx.Analyzers/CliFx.Analyzers.csproj

@@ -3,14 +3,20 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
-    <Nullable>annotations</Nullable>
+    <GenerateDependencyFile>true</GenerateDependencyFile>
     <NoWarn>$(NoWarn);RS1025;RS1026</NoWarn>
   </PropertyGroup>
+  
+  <PropertyGroup>
+    <!--
+      Because this project only has a single target framework, the condition in
+      Directory.Build.props does not appear to work. This is a workaround for that.
+    -->
+    <Nullable>annotations</Nullable>
+  </PropertyGroup>
 
   <ItemGroup>
-    <!-- Keep this dependency as low as possible since we can't bundle it -->
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" PrivateAssets="all" />
-    <!-- https://github.com/Tyrrrz/CliFx/issues/127 -->
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.8.0" PrivateAssets="all" />
   </ItemGroup>
 
 </Project>

CliFx.Analyzers/ObjectModel/CommandOptionSymbol.cs

@@ -13,6 +13,8 @@ internal partial class CommandOptionSymbol : ICommandMemberSymbol
 
     public char? ShortName { get; }
 
+    public bool? IsRequired { get; }
+
     public ITypeSymbol? ConverterType { get; }
 
     public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; }
@@ -21,12 +23,14 @@ internal partial class CommandOptionSymbol : ICommandMemberSymbol
         IPropertySymbol property,
         string? name,
         char? shortName,
+        bool? isRequired,
         ITypeSymbol? converterType,
         IReadOnlyList<ITypeSymbol> validatorTypes)
     {
         Property = property;
         Name = name;
         ShortName = shortName;
+        IsRequired = isRequired;
         ConverterType = converterType;
         ValidatorTypes = validatorTypes;
     }
@@ -56,6 +60,12 @@ internal partial class CommandOptionSymbol
             .Select(a => a.Value)
             .FirstOrDefault() as char?;
 
+        var isRequired = attribute
+            .NamedArguments
+            .Where(a => a.Key == "IsRequired")
+            .Select(a => a.Value.Value)
+            .FirstOrDefault() as bool?;
+
         var converter = attribute
             .NamedArguments
             .Where(a => a.Key == "Converter")
@@ -71,7 +81,7 @@ internal partial class CommandOptionSymbol
             .Cast<ITypeSymbol>()
             .ToArray();
 
-        return new CommandOptionSymbol(property, name, shortName, converter, validators);
+        return new CommandOptionSymbol(property, name, shortName, isRequired, converter, validators);
     }
 
     public static bool IsOptionProperty(IPropertySymbol property) =>

CliFx.Analyzers/OptionMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -0,0 +1,49 @@
+using CliFx.Analyzers.ObjectModel;
+using CliFx.Analyzers.Utils.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace CliFx.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+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,
+        IPropertySymbol property)
+    {
+        if (property.ContainingType is null)
+            return;
+
+        if (!property.IsRequired)
+            return;
+
+        var option = CommandOptionSymbol.TryResolve(property);
+        if (option is null)
+            return;
+
+        if (option.IsRequired != false)
+            return;
+
+        context.ReportDiagnostic(
+            CreateDiagnostic(
+                propertyDeclaration.Identifier.GetLocation()
+            )
+        );
+    }
+
+    public override void Initialize(AnalysisContext context)
+    {
+        base.Initialize(context);
+        context.HandlePropertyDeclaration(Analyze);
+    }
+}

CliFx.Analyzers/ParameterMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -0,0 +1,49 @@
+using CliFx.Analyzers.ObjectModel;
+using CliFx.Analyzers.Utils.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace CliFx.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+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,
+        IPropertySymbol property)
+    {
+        if (property.ContainingType is null)
+            return;
+
+        if (!property.IsRequired)
+            return;
+
+        var parameter = CommandParameterSymbol.TryResolve(property);
+        if (parameter is null)
+            return;
+
+        if (parameter.IsRequired != false)
+            return;
+
+        context.ReportDiagnostic(
+            CreateDiagnostic(
+                propertyDeclaration.Identifier.GetLocation()
+            )
+        );
+    }
+
+    public override void Initialize(AnalysisContext context)
+    {
+        base.Initialize(context);
+        context.HandlePropertyDeclaration(Analyze);
+    }
+}

CliFx.Benchmarks/CliFx.Benchmarks.csproj

@@ -2,16 +2,16 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.1" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.2" />
     <PackageReference Include="clipr" Version="1.6.1" />
-    <PackageReference Include="Cocona" Version="2.0.3" />
+    <PackageReference Include="Cocona" Version="2.1.0" />
     <PackageReference Include="CommandLineParser" Version="2.9.1" />
-    <PackageReference Include="McMaster.Extensions.CommandLineUtils" Version="4.0.1" />
+    <PackageReference Include="McMaster.Extensions.CommandLineUtils" Version="4.0.2" />
-    <PackageReference Include="PowerArgs" Version="3.6.0" />
+    <PackageReference Include="PowerArgs" Version="4.0.0" />
     <PackageReference Include="System.CommandLine" Version="2.0.0-beta1.20574.7" />
   </ItemGroup>
 

CliFx.Demo/CliFx.Demo.csproj

@@ -2,12 +2,12 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
   </ItemGroup>
 
   <ItemGroup>

CliFx.Demo/Commands/BookAddCommand.cs

@@ -14,10 +14,10 @@ public partial class BookAddCommand : ICommand
     private readonly LibraryProvider _libraryProvider;
 
     [CommandParameter(0, Name = "title", Description = "Book title.")]
-    public string Title { get; init; } = "";
+    public required string Title { get; init; }
 
     [CommandOption("author", 'a', IsRequired = true, Description = "Book author.")]
-    public string Author { get; init; } = "";
+    public required string Author { get; init; }
 
     [CommandOption("published", 'p', Description = "Book publish date.")]
     public DateTimeOffset Published { get; init; } = CreateRandomDate();

CliFx.Demo/Commands/BookCommand.cs

@@ -13,7 +13,7 @@ public class BookCommand : ICommand
     private readonly LibraryProvider _libraryProvider;
 
     [CommandParameter(0, Name = "title", Description = "Title of the book to retrieve.")]
-    public string Title { get; init; } = "";
+    public required string Title { get; init; }
 
     public BookCommand(LibraryProvider libraryProvider)
     {

CliFx.Demo/Commands/BookRemoveCommand.cs

@@ -12,7 +12,7 @@ public class BookRemoveCommand : ICommand
     private readonly LibraryProvider _libraryProvider;
 
     [CommandParameter(0, Name = "title", Description = "Title of the book to remove.")]
-    public string Title { get; init; } = "";
+    public required string Title { get; init; }
 
     public BookRemoveCommand(LibraryProvider libraryProvider)
     {

CliFx.Demo/Readme.md

@@ -2,4 +2,4 @@
 
 Sample command line interface for managing a library of books.
 
-This demo project showcases basic CliFx functionality such as command routing, argument parsing, autogenerated help text.
+This demo project showcases basic CliFx functionality such as command routing, argument parsing, and autogenerated help text.

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

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

CliFx.Tests/CancellationSpecs.cs

@@ -21,28 +21,30 @@ public class CancellationSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public async ValueTask ExecuteAsync(IConsole console)
+                public async ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        try
+                    try
-        {
+                    {
-            await Task.Delay(
+                        await Task.Delay(
-                TimeSpan.FromSeconds(3),
+                            TimeSpan.FromSeconds(3),
-                console.RegisterCancellationHandler()
+                            console.RegisterCancellationHandler()
-            );
+                        );
 
-            console.Output.WriteLine(""Completed successfully"");
+                        console.Output.WriteLine("Completed successfully");
-        }
+                    }
-        catch (OperationCanceledException)
+                    catch (OperationCanceledException)
-        {
+                    {
-            console.Output.WriteLine(""Cancelled"");
+                        console.Output.WriteLine("Cancelled");
-            throw;
+                        throw;
-        }
+                    }
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/CliFx.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -9,16 +9,16 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies" Version="1.2.4" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.1" />
-    <PackageReference Include="CliWrap" Version="3.4.4" />
+    <PackageReference Include="CliWrap" Version="3.5.0" />
-    <PackageReference Include="FluentAssertions" Version="6.7.0" />
+    <PackageReference Include="FluentAssertions" Version="6.8.0" />
-    <PackageReference Include="GitHubActionsTestLogger" Version="2.0.0" PrivateAssets="all" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="2.0.1" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.2.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" />
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="all" />
-    <PackageReference Include="coverlet.collector" Version="3.1.2" PrivateAssets="all" />
+    <PackageReference Include="coverlet.collector" Version="3.2.0" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>
@@ -26,12 +26,4 @@
     <ProjectReference Include="..\CliFx\CliFx.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <None Include="../CliFx.Tests.Dummy/bin/$(Configuration)/$(TargetFramework)/CliFx.Tests.Dummy.runtimeconfig.json">
-      <Link>CliFx.Tests.Dummy.runtimeconfig.json</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <Visible>false</Visible>
-    </None>
-  </ItemGroup>
-
 </Project>

CliFx.Tests/ConsoleSpecs.cs

@@ -48,27 +48,28 @@ public class ConsoleSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{   
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.ResetColor();
+                    console.ResetColor();
-        console.ForegroundColor = ConsoleColor.DarkMagenta;
+                    console.ForegroundColor = ConsoleColor.DarkMagenta;
-        console.BackgroundColor = ConsoleColor.DarkMagenta;
+                    console.BackgroundColor = ConsoleColor.DarkMagenta;
-        console.WindowWidth = 100;
+                    console.WindowWidth = 100;
-        console.WindowHeight = 25;
+                    console.WindowHeight = 25;
-        console.CursorLeft = 42;
+                    console.CursorLeft = 42;
-        console.CursorTop = 24;
+                    console.CursorTop = 24;
 
-        console.Output.WriteLine(""Hello "");
+                    console.Output.WriteLine("Hello ");
-        console.Error.WriteLine(""world!"");
+                    console.Error.WriteLine("world!");
 
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -108,20 +109,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{   
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        var input = console.Input.ReadToEnd();
+                    var input = console.Input.ReadToEnd();
-        console.Output.WriteLine(input);
+                    console.Output.WriteLine(input);
-        console.Error.WriteLine(input);
+                    console.Error.WriteLine(input);
 
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -151,20 +153,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{   
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(console.ReadKey().Key);
+                    console.Output.WriteLine(console.ReadKey().Key);
-        console.Output.WriteLine(console.ReadKey().Key);
+                    console.Output.WriteLine(console.ReadKey().Key);
-        console.Output.WriteLine(console.ReadKey().Key);
+                    console.Output.WriteLine(console.ReadKey().Key);
 
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/ConversionSpecs.cs

@@ -21,20 +21,22 @@ public class ConversionSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -59,20 +61,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public object Foo { get; set; }
+                public object Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -97,25 +101,27 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public bool Foo { get; set; }
+                public bool Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public bool Bar { get; set; }
+                public bool Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -143,20 +149,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public bool Foo { get; set; }
+                public bool Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -181,20 +189,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public int Foo { get; set; }
+                public int Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -219,20 +229,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public double Foo { get; set; }
+                public double Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo.ToString(CultureInfo.InvariantCulture));
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo.ToString(CultureInfo.InvariantCulture));
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -257,20 +269,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public DateTimeOffset Foo { get; set; }
+                public DateTimeOffset Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo.ToString("u", CultureInfo.InvariantCulture));
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo.ToString(""u"", CultureInfo.InvariantCulture));
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -295,20 +309,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public TimeSpan Foo { get; set; }
+                public TimeSpan Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo.ToString(null, CultureInfo.InvariantCulture));
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo.ToString(null, CultureInfo.InvariantCulture));
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -333,22 +349,24 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One = 1, Two = 2, Three = 3 }
+            public enum CustomEnum { One = 1, Two = 2, Three = 3 }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomEnum Foo { get; set; }
+                public CustomEnum Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine((int) Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine((int) Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -373,25 +391,27 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public int? Foo { get; set; }
+                public int? Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public int? Bar { get; set; }
+                public int? Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -419,27 +439,29 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One = 1, Two = 2, Three = 3 }
+            public enum CustomEnum { One = 1, Two = 2, Three = 3 }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomEnum? Foo { get; set; }
+                public CustomEnum? Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public CustomEnum? Bar { get; set; }
+                public CustomEnum? Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + (int?) Foo);
+                    console.Output.WriteLine("Foo = " + (int?) Foo);
-        console.Output.WriteLine(""Bar = "" + (int?) Bar);
+                    console.Output.WriteLine("Bar = " + (int?) Bar);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -467,27 +489,29 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomType
+            public class CustomType
-{
+            {
-    public string Value { get; }
+                public string Value { get; }
 
-    public CustomType(string value) => Value = value;
+                public CustomType(string value) => Value = value;
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomType Foo { get; set; }
+                public CustomType Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo.Value);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo.Value);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -512,45 +536,47 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomTypeA
+            public class CustomTypeA
-{
+            {
-    public string Value { get; }
+                public string Value { get; }
 
-    private CustomTypeA(string value) => Value = value;
+                private CustomTypeA(string value) => Value = value;
 
-    public static CustomTypeA Parse(string value) => 
+                public static CustomTypeA Parse(string value) =>
-        new CustomTypeA(value);
+                    new CustomTypeA(value);
-}
+            }
 
-public class CustomTypeB
+            public class CustomTypeB
-{
+            {
-    public string Value { get; }
+                public string Value { get; }
 
-    private CustomTypeB(string value) => Value = value;
+                private CustomTypeB(string value) => Value = value;
 
-    public static CustomTypeB Parse(string value, IFormatProvider formatProvider) =>
+                public static CustomTypeB Parse(string value, IFormatProvider formatProvider) =>
-        new CustomTypeB(value);
+                    new CustomTypeB(value);
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomTypeA Foo { get; set; }
+                public CustomTypeA Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public CustomTypeB Bar { get; set; }
+                public CustomTypeB Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo.Value);
+                    console.Output.WriteLine("Foo = " + Foo.Value);
-        console.Output.WriteLine(""Bar = "" + Bar.Value);
+                    console.Output.WriteLine("Bar = " + Bar.Value);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -578,26 +604,28 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomConverter : BindingConverter<int>
+            public class CustomConverter : BindingConverter<int>
-{
+            {
-    public override int Convert(string rawValue) =>
+                public override int Convert(string rawValue) =>
-        rawValue.Length;
+                    rawValue.Length;
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f', Converter = typeof(CustomConverter))]
+                [CommandOption('f', Converter = typeof(CustomConverter))]
-    public int Foo { get; set; }
+                public int Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console)
+                {
+                    console.Output.WriteLine(Foo);
+                    return default;
+                }
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console)
-    {
-        console.Output.WriteLine(Foo);
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -622,22 +650,24 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public string[] Foo { get; set; }
+                public string[] Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -666,22 +696,24 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -710,22 +742,24 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public List<string> Foo { get; set; }
+                public List<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -754,22 +788,24 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public int[] Foo { get; set; }
+                public int[] Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
+
+                    return default;
+                }
+            }
+            """
+        );
 
-        return default;
-    }
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -798,16 +834,18 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public int Foo { get; set; }
+                public int Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -832,18 +870,20 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomType {}
+            public class CustomType {}
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomType Foo { get; set; }
+                public CustomType Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -868,23 +908,25 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomType : IEnumerable<object>
+            public class CustomType : IEnumerable<object>
-{
+            {
-    public IEnumerator<object> GetEnumerator() => Enumerable.Empty<object>().GetEnumerator();
+                public IEnumerator<object> GetEnumerator() => Enumerable.Empty<object>().GetEnumerator();
 
-    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+                IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomType Foo { get; set; }
+                public CustomType Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -909,26 +951,28 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class ValidatorA : BindingValidator<int>
+            public class ValidatorA : BindingValidator<int>
-{
+            {
-    public override BindingValidationError Validate(int value) => Ok();
+                public override BindingValidationError Validate(int value) => Ok();
-}
+            }
 
-public class ValidatorB : BindingValidator<int>
+            public class ValidatorB : BindingValidator<int>
-{
+            {
-    public override BindingValidationError Validate(int value) => Error(""Hello world"");
+                public override BindingValidationError Validate(int value) => Error("Hello world");
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f', Validators = new[] {typeof(ValidatorA), typeof(ValidatorB)})]
+                [CommandOption('f', Validators = new[] {typeof(ValidatorA), typeof(ValidatorB)})]
-    public int Foo { get; set; }
+                public int Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
@@ -953,25 +997,27 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public class CustomType
+            public class CustomType
-{
+            {
-    public string Value { get; }
+                public string Value { get; }
 
-    private CustomType(string value) => Value = value;
+                private CustomType(string value) => Value = value;
 
-    public static CustomType Parse(string value) => throw new Exception(""Hello world"");
+                public static CustomType Parse(string value) => throw new Exception("Hello world");
-}
+            }
 
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public CustomType Foo { get; set; }
+                public CustomType Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)

CliFx.Tests/DirectivesSpecs.cs

@@ -75,13 +75,14 @@ public class DirectivesSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command(""cmd"")]
+            [Command("cmd")]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/EnvironmentSpecs.cs

@@ -25,20 +25,21 @@ public class EnvironmentSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", IsRequired = true, EnvironmentVariable = ""ENV_FOO"")]
+                [CommandOption("foo", IsRequired = true, EnvironmentVariable = "ENV_FOO")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -67,20 +68,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", EnvironmentVariable = ""ENV_FOO"")]
+                [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -109,22 +111,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", EnvironmentVariable = ""ENV_FOO"")]
+                [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -156,20 +159,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", EnvironmentVariable = ""ENV_FOO"")]
+                [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -198,20 +202,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", EnvironmentVariable = ""ENV_FOO"")]
+                [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/ErrorReportingSpecs.cs

@@ -22,14 +22,15 @@ public class ErrorReportingSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) =>
+                public ValueTask ExecuteAsync(IConsole console) =>
-        throw new Exception(""Something went wrong"");
+                    throw new Exception("Something went wrong");
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -60,14 +61,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) =>
+                public ValueTask ExecuteAsync(IConsole console) =>
-        throw new Exception(""Something went wrong"", new Exception(""Another exception""));
+                    throw new Exception("Something went wrong", new Exception("Another exception"));
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -99,14 +101,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) =>
+                public ValueTask ExecuteAsync(IConsole console) =>
-        throw new CommandException(""Something went wrong"", 69);
+                    throw new CommandException("Something went wrong", 69);
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -134,14 +137,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) =>
+                public ValueTask ExecuteAsync(IConsole console) =>
-        throw new CommandException("""", 69);
+                    throw new CommandException("", 69);
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -172,14 +176,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) =>
+                public ValueTask ExecuteAsync(IConsole console) =>
-        throw new CommandException(""Something went wrong"", 69, true);
+                    throw new CommandException("Something went wrong", 69, true);
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/HelpTextSpecs.cs

@@ -44,13 +44,14 @@ public class HelpTextSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -77,19 +78,20 @@ public class DefaultCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command(""cmd"")]
+            [Command("cmd")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
 
-[Command(""cmd child"")]
+            [Command("cmd child")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -116,25 +118,26 @@ public class NamedChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
 
-[Command(""cmd"", Description = ""Description of a named command."")]
+            [Command("cmd", Description = "Description of a named command.")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
 
-[Command(""cmd child"")]
+            [Command("cmd child")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -160,25 +163,26 @@ public class NamedChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
 
-[Command(""cmd"")]
+            [Command("cmd")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
 
-[Command(""cmd child"", Description = ""Description of a named child command."")]
+            [Command("cmd child", Description = "Description of a named child command.")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -257,13 +261,15 @@ public class NamedChildCommand : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command(Description = ""Description of the default command."")]
+                
-public class DefaultCommand : ICommand
+                [Command(Description = "Description of the default command.")]
-{
+                public class DefaultCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
-");
+                }
+
+                """);
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -292,19 +298,21 @@ public class DefaultCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+                
-public class DefaultCommand : ICommand
+                [Command]
-{
+                public class DefaultCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd")]
+                public class NamedCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command(""cmd"")]
+                """);
-public class NamedCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -333,22 +341,24 @@ public class NamedCommand : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+                
-public class Command : ICommand
+                [Command]
-{
+                public class Command : ICommand
-    [CommandParameter(0)]
+                {
-    public string Foo { get; set; }
+                    [CommandParameter(0)]
+                    public string Foo { get; set; }
+                
+                    [CommandParameter(1)]
+                    public string Bar { get; set; }
+                
+                    [CommandParameter(2)]
+                    public IReadOnlyList<string> Baz { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-    [CommandParameter(1)]
+                """);
-    public string Bar { get; set; }
-
-    [CommandParameter(2)]
-    public IReadOnlyList<string> Baz { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -378,28 +388,30 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-// Base members appear last in reflection order
+                
-public abstract class CommandBase : ICommand
+                // Base members appear last in reflection order
-{
+                public abstract class CommandBase : ICommand
-    [CommandParameter(0)]
+                {
-    public string Foo { get; set; }
+                    [CommandParameter(0)]
+                    public string Foo { get; set; }
+                
+                    public abstract ValueTask ExecuteAsync(IConsole console);
+                }
+                
+                [Command]
+                public class Command : CommandBase
+                {
+                    [CommandParameter(2)]
+                    public IReadOnlyList<string> Baz { get; set; }
+                
+                    [CommandParameter(1)]
+                    public string Bar { get; set; }
+                
+                    public override ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-    public abstract ValueTask ExecuteAsync(IConsole console);
+                """);
-}
-
-[Command]
-public class Command : CommandBase
-{
-    [CommandParameter(2)]
-    public IReadOnlyList<string> Baz { get; set; }
-
-    [CommandParameter(1)]
-    public string Bar { get; set; }
-
-    public override ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -428,22 +440,24 @@ public class Command : CommandBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+                
-public class Command : ICommand
+                [Command]
-{
+                public class Command : ICommand
-    [CommandOption(""foo"", IsRequired = true)]
+                {
-    public string Foo { get; set; }
+                    [CommandOption("foo", IsRequired = true)]
+                    public string Foo { get; set; }
+                
+                    [CommandOption("bar")]
+                    public string Bar { get; set; }
+                
+                    [CommandOption("baz", IsRequired = true)]
+                    public IReadOnlyList<string> Baz { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-    [CommandOption(""bar"")]
+                """);
-    public string Bar { get; set; }
-
-    [CommandOption(""baz"", IsRequired = true)]
-    public IReadOnlyList<string> Baz { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -472,19 +486,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+                
-public class Command : ICommand
+                [Command]
-{
+                public class Command : ICommand
-    [CommandParameter(0, Name = ""foo"", Description = ""Description of foo."")]
+                {
-    public string Foo { get; set; }
+                    [CommandParameter(0, Name = "foo", Description = "Description of foo.")]
+                    public string Foo { get; set; }
+                
+                    [CommandOption("bar", Description = "Description of bar.")]
+                    public string Bar { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-    [CommandOption(""bar"", Description = ""Description of bar."")]
+                """);
-    public string Bar { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -515,13 +531,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+                
-public class Command : ICommand
+                [Command]
-{
+                public class Command : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
-");
+                }
+
+                """);
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -551,13 +569,15 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command(""cmd"")]
+                
-public class Command : ICommand
+                [Command("cmd")]
-{
+                public class Command : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
-");
+                }
+
+                """);
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -589,21 +609,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One, Two, Three }
+                
+                public enum CustomEnum { One, Two, Three }
+                
+                [Command]
+                public class Command : ICommand
+                {
+                    [CommandParameter(0)]
+                    public CustomEnum Foo { get; set; }
+                
+                    [CommandOption("bar")]
+                    public CustomEnum Bar { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command]
+                """);
-public class Command : ICommand
-{
-    [CommandParameter(0)]
-    public CustomEnum Foo { get; set; }
-
-    [CommandOption(""bar"")]
-    public CustomEnum Bar { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -634,21 +656,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One, Two, Three }
+                
+                public enum CustomEnum { One, Two, Three }
+                
+                [Command]
+                public class Command : ICommand
+                {
+                    [CommandParameter(0)]
+                    public IReadOnlyList<CustomEnum> Foo { get; set; }
+                
+                    [CommandOption("bar")]
+                    public IReadOnlyList<CustomEnum> Bar { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command]
+                """);
-public class Command : ICommand
-{
-    [CommandParameter(0)]
-    public IReadOnlyList<CustomEnum> Foo { get; set; }
-
-    [CommandOption(""bar"")]
-    public IReadOnlyList<CustomEnum> Bar { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -679,21 +703,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One, Two, Three }
+                
+                public enum CustomEnum { One, Two, Three }
+                
+                [Command]
+                public class Command : ICommand
+                {
+                    [CommandParameter(0)]
+                    public CustomEnum? Foo { get; set; }
+                
+                    [CommandOption("bar")]
+                    public IReadOnlyList<CustomEnum?> Bar { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command]
+                """);
-public class Command : ICommand
-{
-    [CommandParameter(0)]
-    public CustomEnum? Foo { get; set; }
-
-    [CommandOption(""bar"")]
-    public IReadOnlyList<CustomEnum?> Bar { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -724,21 +750,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One, Two, Three }
+                
+                public enum CustomEnum { One, Two, Three }
+                
+                [Command]
+                public class Command : ICommand
+                {
+                    [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
+                    public CustomEnum Foo { get; set; }
+                
+                    [CommandOption("bar", EnvironmentVariable = "ENV_BAR")]
+                    public CustomEnum Bar { get; set; }
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command]
+                """);
-public class Command : ICommand
-{
-    [CommandOption(""foo"", EnvironmentVariable = ""ENV_FOO"")]
-    public CustomEnum Foo { get; set; }
-
-    [CommandOption(""bar"", EnvironmentVariable = ""ENV_BAR"")]
-    public CustomEnum Bar { get; set; }
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -768,39 +796,41 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public enum CustomEnum { One, Two, Three }
+                
+                public enum CustomEnum { One, Two, Three }
+                
+                [Command]
+                public class Command : ICommand
+                {
+                    [CommandOption("foo")]
+                    public object Foo { get; set; } = 42;
+                
+                    [CommandOption("bar")]
+                    public string Bar { get; set; } = "hello";
+                
+                    [CommandOption("baz")]
+                    public IReadOnlyList<string> Baz { get; set; } = new[] {"one", "two", "three"};
+                
+                    [CommandOption("qwe")]
+                    public bool Qwe { get; set; } = true;
+                
+                    [CommandOption("qop")]
+                    public int? Qop { get; set; } = 1337;
+                
+                    [CommandOption("zor")]
+                    public TimeSpan Zor { get; set; } = TimeSpan.FromMinutes(123);
+                
+                    [CommandOption("lol")]
+                    public CustomEnum Lol { get; set; } = CustomEnum.Two;
+                
+                    [CommandOption("hmm", IsRequired = true)]
+                    public string Hmm { get; set; } = "not printed";
+                
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command]
+                """);
-public class Command : ICommand
-{
-    [CommandOption(""foo"")]
-    public object Foo { get; set; } = 42;
-
-    [CommandOption(""bar"")]
-    public string Bar { get; set; } = ""hello"";
-
-    [CommandOption(""baz"")]
-    public IReadOnlyList<string> Baz { get; set; } = new[] {""one"", ""two"", ""three""};
-
-    [CommandOption(""qwe"")]
-    public bool Qwe { get; set; } = true;
-
-    [CommandOption(""qop"")]
-    public int? Qop { get; set; } = 1337;
-
-    [CommandOption(""zor"")]
-    public TimeSpan Zor { get; set; } = TimeSpan.FromMinutes(123);
-
-    [CommandOption(""lol"")]
-    public CustomEnum Lol { get; set; } = CustomEnum.Two;
-
-    [CommandOption(""hmm"", IsRequired = true)]
-    public string Hmm { get; set; } = ""not printed"";
-
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -836,25 +866,27 @@ public class Command : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command(""cmd1"", Description = ""Description of one command."")]
+                
-public class FirstCommand : ICommand
+                [Command("cmd1", Description = "Description of one command.")]
-{
+                public class FirstCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2", Description = "Description of another command.")]
+                public class SecondCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2 child", Description = "Description of another command's child command.")]
+                public class SecondCommandChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command(""cmd2"", Description = ""Description of another command."")]
+                """);
-public class SecondCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-
-[Command(""cmd2 child"", Description = ""Description of another command's child command."")]
-public class SecondCommandChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -890,37 +922,39 @@ public class SecondCommandChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command(""cmd1"")]
+                
-public class FirstCommand : ICommand
+                [Command("cmd1")]
-{
+                public class FirstCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd1 child1")]
+                public class FirstCommandFirstChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2")]
+                public class SecondCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2 child11")]
+                public class SecondCommandFirstChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2 child2")]
+                public class SecondCommandSecondChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command(""cmd1 child1"")]
+                """);
-public class FirstCommandFirstChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-
-[Command(""cmd2"")]
-public class SecondCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-
-[Command(""cmd2 child11"")]
-public class SecondCommandFirstChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-
-[Command(""cmd2 child2"")]
-public class SecondCommandSecondChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -950,25 +984,27 @@ public class SecondCommandSecondChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command(""cmd1"")]
+                
-public class FirstCommand : ICommand
+                [Command("cmd1")]
-{
+                public class FirstCommand : ICommand
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                {
-}
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2 child1")]
+                public class SecondCommandFirstChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
+                
+                [Command("cmd2 child2")]
+                public class SecondCommandSecondChildCommand : ICommand
+                {
+                    public ValueTask ExecuteAsync(IConsole console) => default;
+                }
 
-[Command(""cmd2 child1"")]
+                """);
-public class SecondCommandFirstChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-
-[Command(""cmd2 child2"")]
-public class SecondCommandSecondChildCommand : ICommand
-{
-    public ValueTask ExecuteAsync(IConsole console) => default;
-}
-");
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)

CliFx.Tests/OptionBindingSpecs.cs

@@ -22,19 +22,21 @@ public class OptionBindingSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public bool Foo { get; set; }
+                public bool Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -60,19 +62,21 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public bool Foo { get; set; }
+                public bool Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -98,24 +102,26 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandOption(""bar"")]
+                [CommandOption("bar")]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -144,24 +150,26 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -190,24 +198,26 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandOption('b')]
+                [CommandOption('b')]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -236,21 +246,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""Foo"")]
+                [CommandOption("Foo")]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -280,21 +292,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -324,21 +338,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -368,21 +384,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption('f')]
+                [CommandOption('f')]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -412,21 +430,23 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", 'f')]
+                [CommandOption("foo", 'f')]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        foreach (var i in Foo)
+                    foreach (var i in Foo)
-            console.Output.WriteLine(i);
+                        console.Output.WriteLine(i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -456,24 +476,26 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandOption(""bar"")]
+                [CommandOption("bar")]
-    public string Bar { get; set; } = ""hello"";
+                public string Bar { get; set; } = "hello";
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -502,55 +524,56 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-public static class SharedContext
+            public static class SharedContext
-{
+            {
-    public static int Foo { get; set; }
+                public static int Foo { get; set; }
 
-    public static bool Bar { get; set; }
+                public static bool Bar { get; set; }
-}
+            }
 
-public interface IHasFoo : ICommand
+            public interface IHasFoo : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public int Foo
+                public int Foo
-    {
+                {
-        get => SharedContext.Foo;
+                    get => SharedContext.Foo;
-        set => SharedContext.Foo = value;
+                    set => SharedContext.Foo = value;
-    }
+                }
-}
+            }
 
-public interface IHasBar : ICommand
+            public interface IHasBar : ICommand
-{
+            {
-    [CommandOption(""bar"")]
+                [CommandOption("bar")]
-    public bool Bar
+                public bool Bar
-    {
+                {
-        get => SharedContext.Bar;
+                    get => SharedContext.Bar;
-        set => SharedContext.Bar = value;
+                    set => SharedContext.Bar = value;
-    }
+                }
-}
+            }
 
-public interface IHasBaz : ICommand
+            public interface IHasBaz : ICommand
-{
+            {
-    public string Baz { get; set; }
+                public string Baz { get; set; }
-}
+            }
 
-[Command]
+            [Command]
-public class Command : IHasFoo, IHasBar, IHasBaz
+            public class Command : IHasFoo, IHasBar, IHasBaz
-{
+            {
-    [CommandOption(""baz"")]
+                [CommandOption("baz")]
-    public string Baz { get; set; }
+                public string Baz { get; set; }
 
-	public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-	{
+                {
-        console.Output.WriteLine(""Foo = "" + SharedContext.Foo);
+                    console.Output.WriteLine("Foo = " + SharedContext.Foo);
-        console.Output.WriteLine(""Bar = "" + SharedContext.Bar);
+                    console.Output.WriteLine("Bar = " + SharedContext.Bar);
-        console.Output.WriteLine(""Baz = "" + Baz);
+                    console.Output.WriteLine("Baz = " + Baz);
 
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -579,20 +602,22 @@ public class Command : IHasFoo, IHasBar, IHasBaz
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(Foo);
+                    console.Output.WriteLine(Foo);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -618,15 +643,17 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", IsRequired = true)]
+                [CommandOption("foo", IsRequired = true)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -652,15 +679,17 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", IsRequired = true)]
+                [CommandOption("foo", IsRequired = true)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -686,15 +715,17 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"", IsRequired = true)]
+                [CommandOption("foo", IsRequired = true)]
-    public IReadOnlyList<string> Foo { get; set; }
+                public IReadOnlyList<string> Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -720,15 +751,17 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -754,15 +787,17 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandOption(""foo"")]
+                [CommandOption("foo")]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -781,4 +816,40 @@ public class Command : ICommand
         exitCode.Should().NotBe(0);
         stdErr.Should().Contain("expects a single argument, but provided with multiple");
     }
+
+    [Fact]
+    public async Task Option_binding_fails_if_a_required_property_option_has_not_been_provided()
+    {
+        // Arrange
+        var commandType = DynamicCommandBuilder.Compile(
+            // language=cs
+            """
+            [Command]
+            public class Command : ICommand
+            {
+                [CommandOption("foo")]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
+
+        var application = new CliApplicationBuilder()
+            .AddCommand(commandType)
+            .UseConsole(FakeConsole)
+            .Build();
+
+        // Act
+        var exitCode = await application.RunAsync(
+            Array.Empty<string>(),
+            new Dictionary<string, string>()
+        );
+
+        var stdErr = FakeConsole.ReadErrorString();
+
+        // Assert
+        exitCode.Should().NotBe(0);
+        stdErr.Should().Contain("Missing required option(s)");
+    }
 }

CliFx.Tests/ParameterBindingSpecs.cs

@@ -21,24 +21,26 @@ public class ParameterBindingSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1)]
+                [CommandParameter(1)]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -67,33 +69,35 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1)]
+                [CommandParameter(1)]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    [CommandParameter(2)]
+                [CommandParameter(2)]
-    public IReadOnlyList<string> Baz { get; set; }
+                public IReadOnlyList<string> Baz { get; set; }
 
-    [CommandOption(""boo"")]
+                [CommandOption("boo")]
-    public string Boo { get; set; }
+                public string Boo { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        foreach (var i in Baz)
+                    foreach (var i in Baz)
-            console.Output.WriteLine(""Baz = "" + i);
+                        console.Output.WriteLine("Baz = " + i);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -125,24 +129,26 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1, IsRequired = false)]
+                [CommandParameter(1, IsRequired = false)]
-    public string Bar { get; set; } = ""xyz"";
+                public string Bar { get; set; } = "xyz";
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""Foo = "" + Foo);
+                    console.Output.WriteLine("Foo = " + Foo);
-        console.Output.WriteLine(""Bar = "" + Bar);
+                    console.Output.WriteLine("Bar = " + Bar);
 
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -171,18 +177,20 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1)]
+                [CommandParameter(1)]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -208,18 +216,20 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1)]
+                [CommandParameter(1)]
-    public IReadOnlyList<string> Bar { get; set; }
+                public IReadOnlyList<string> Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -245,18 +255,20 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    [CommandParameter(0)]
+                [CommandParameter(0)]
-    public string Foo { get; set; }
+                public string Foo { get; set; }
 
-    [CommandParameter(1)]
+                [CommandParameter(1)]
-    public string Bar { get; set; }
+                public string Bar { get; set; }
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/RoutingSpecs.cs

@@ -21,37 +21,38 @@ public class RoutingSpecs : SpecsBase
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""default"");
+                    console.Output.WriteLine("default");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd"")]
+            [Command("cmd")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd"");
+                    console.Output.WriteLine("cmd");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd child"")]
+            [Command("cmd child")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd child"");
+                    console.Output.WriteLine("cmd child");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -77,37 +78,38 @@ public class NamedChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""default"");
+                    console.Output.WriteLine("default");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd"")]
+            [Command("cmd")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd"");
+                    console.Output.WriteLine("cmd");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd child"")]
+            [Command("cmd child")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd child"");
+                    console.Output.WriteLine("cmd child");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)
@@ -133,37 +135,38 @@ public class NamedChildCommand : ICommand
         // Arrange
         var commandTypes = DynamicCommandBuilder.CompileMany(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class DefaultCommand : ICommand
+            public class DefaultCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""default"");
+                    console.Output.WriteLine("default");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd"")]
+            [Command("cmd")]
-public class NamedCommand : ICommand
+            public class NamedCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd"");
+                    console.Output.WriteLine("cmd");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
 
-[Command(""cmd child"")]
+            [Command("cmd child")]
-public class NamedChildCommand : ICommand
+            public class NamedChildCommand : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""cmd child"");
+                    console.Output.WriteLine("cmd child");
-        return default;
+                    return default;
-    }
+                }
-}
+            }
-");
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommands(commandTypes)

CliFx.Tests/TypeActivationSpecs.cs

@@ -23,16 +23,18 @@ public class TypeActivationSpecs : SpecsBase
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""foo"");
+                    console.Output.WriteLine("foo");
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -59,14 +61,16 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public Command(string foo) {}
+                public Command(string foo) {}
 
-    public ValueTask ExecuteAsync(IConsole console) => default;
+                public ValueTask ExecuteAsync(IConsole console) => default;
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -93,20 +97,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    private readonly string _foo;
+                private readonly string _foo;
 
-    public Command(string foo) => _foo = foo;
+                public Command(string foo) => _foo = foo;
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(_foo);
+                    console.Output.WriteLine(_foo);
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
@@ -133,20 +139,22 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    private readonly string _foo;
+                private readonly string _foo;
 
-    public Command(string foo) => _foo = foo;
+                public Command(string foo) => _foo = foo;
 
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(_foo);
+                    console.Output.WriteLine(_foo);
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var serviceProvider = new ServiceCollection()
             .AddSingleton(commandType, Activator.CreateInstance(commandType, "Hello world")!)
@@ -177,16 +185,18 @@ public class Command : ICommand
         // Arrange
         var commandType = DynamicCommandBuilder.Compile(
             // language=cs
-            @"
+            """
-[Command]
+            [Command]
-public class Command : ICommand
+            public class Command : ICommand
-{
+            {
-    public ValueTask ExecuteAsync(IConsole console)
+                public ValueTask ExecuteAsync(IConsole console)
-    {
+                {
-        console.Output.WriteLine(""foo"");
+                    console.Output.WriteLine("foo");
-        return default;
+                    return default;
-    }
+                }
-}");
+            }
+            """
+        );
 
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)

CliFx.Tests/Utils/DynamicCommandBuilder.cs

@@ -61,7 +61,7 @@ internal static class DynamicCommandBuilder
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
             new[] {ast},
-            ReferenceAssemblies.Net50
+            Net70.References.All
                 .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location))
                 .Append(MetadataReference.CreateFromFile(typeof(DynamicCommandBuilder).Assembly.Location)),
             // DLL to avoid having to define the Main() method
@@ -76,9 +76,10 @@ internal static class DynamicCommandBuilder
         if (compilationErrors.Any())
         {
             throw new InvalidOperationException(
-                "Failed to compile code." +
+                $"""
-                Environment.NewLine +
+                Failed to compile code.
-                string.Join(Environment.NewLine, compilationErrors.Select(e => e.ToString()))
+                {string.Join(Environment.NewLine, compilationErrors.Select(e => e.ToString()))}
+                """
             );
         }
 
@@ -94,9 +95,10 @@ internal static class DynamicCommandBuilder
         if (emitErrors.Any())
         {
             throw new InvalidOperationException(
-                "Failed to emit code." +
+                $"""
-                Environment.NewLine +
+                Failed to emit code.
-                string.Join(Environment.NewLine, emitErrors.Select(e => e.ToString()))
+                {string.Join(Environment.NewLine, emitErrors.Select(e => e.ToString()))}
+                """
             );
         }
 

CliFx/ApplicationConfiguration.cs

@@ -24,7 +24,7 @@ public class ApplicationConfiguration
     public bool IsPreviewModeAllowed { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ApplicationConfiguration"/>.
+    /// Initializes an instance of <see cref="ApplicationConfiguration" />.
     /// </summary>
     public ApplicationConfiguration(
         IReadOnlyList<Type> commandTypes,

CliFx/ApplicationMetadata.cs

@@ -26,7 +26,7 @@ public class ApplicationMetadata
     public string? Description { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ApplicationMetadata"/>.
+    /// Initializes an instance of <see cref="ApplicationMetadata" />.
     /// </summary>
     public ApplicationMetadata(
         string title,

CliFx/Attributes/CommandAttribute.cs

@@ -26,7 +26,7 @@ public sealed class CommandAttribute : Attribute
     public string? Description { get; set; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CommandAttribute"/>.
+    /// Initializes an instance of <see cref="CommandAttribute" />.
     /// </summary>
     public CommandAttribute(string name)
     {
@@ -34,7 +34,7 @@ public sealed class CommandAttribute : Attribute
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CommandAttribute"/>.
+    /// Initializes an instance of <see cref="CommandAttribute" />.
     /// </summary>
     public CommandAttribute()
     {

CliFx/Attributes/CommandOptionAttribute.cs

@@ -14,7 +14,7 @@ public sealed class CommandOptionAttribute : Attribute
     /// </summary>
     /// <remarks>
     /// Must contain at least two characters and start with a letter.
-    /// Either <see cref="Name"/> or <see cref="ShortName"/> must be set.
+    /// Either <see cref="Name" /> or <see cref="ShortName" /> must be set.
     /// All options in a command must have unique names (comparison IS NOT case-sensitive).
     /// </remarks>
     public string? Name { get; }
@@ -23,7 +23,7 @@ public sealed class CommandOptionAttribute : Attribute
     /// Option short name.
     /// </summary>
     /// <remarks>
-    /// Either <see cref="Name"/> or <see cref="ShortName"/> must be set.
+    /// Either <see cref="Name" /> or <see cref="ShortName" /> must be set.
     /// All options in a command must have unique short names (comparison IS case-sensitive).
     /// </remarks>
     public char? ShortName { get; }
@@ -32,6 +32,10 @@ public sealed class CommandOptionAttribute : Attribute
     /// Whether this option is required (default: <c>false</c>).
     /// If an option is required, the user will get an error if they don't set it.
     /// </summary>
+    /// <remarks>
+    /// You can use the <c>required</c> keyword on the property (introduced in C# 11) to implicitly
+    /// set <see cref="IsRequired" /> to <c>true</c>.
+    /// </remarks>
     public bool IsRequired { get; set; }
 
     /// <summary>
@@ -51,7 +55,7 @@ public sealed class CommandOptionAttribute : Attribute
     /// a value expected by the underlying property.
     /// </summary>
     /// <remarks>
-    /// Converter must derive from <see cref="BindingConverter{T}"/>.
+    /// Converter must derive from <see cref="BindingConverter{T}" />.
     /// </remarks>
     public Type? Converter { get; set; }
 
@@ -60,12 +64,12 @@ public sealed class CommandOptionAttribute : Attribute
     /// property, after it has been bound.
     /// </summary>
     /// <remarks>
-    /// Validators must derive from <see cref="BindingValidator{T}"/>.
+    /// 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"/>.
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
     /// </summary>
     private CommandOptionAttribute(string? name, char? shortName)
     {
@@ -74,7 +78,7 @@ public sealed class CommandOptionAttribute : Attribute
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute"/>.
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
     /// </summary>
     public CommandOptionAttribute(string name, char shortName)
         : this(name, (char?) shortName)
@@ -82,7 +86,7 @@ public sealed class CommandOptionAttribute : Attribute
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute"/>.
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
     /// </summary>
     public CommandOptionAttribute(string name)
         : this(name, null)
@@ -90,7 +94,7 @@ public sealed class CommandOptionAttribute : Attribute
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CommandOptionAttribute"/>.
+    /// Initializes an instance of <see cref="CommandOptionAttribute" />.
     /// </summary>
     public CommandOptionAttribute(char shortName)
         : this(null, (char?) shortName)

CliFx/Attributes/CommandParameterAttribute.cs

@@ -51,7 +51,7 @@ public sealed class CommandParameterAttribute : Attribute
     /// a value expected by the underlying property.
     /// </summary>
     /// <remarks>
-    /// Converter must derive from <see cref="BindingConverter{T}"/>.
+    /// Converter must derive from <see cref="BindingConverter{T}" />.
     /// </remarks>
     public Type? Converter { get; set; }
 
@@ -60,12 +60,12 @@ public sealed class CommandParameterAttribute : Attribute
     /// property, after it has been bound.
     /// </summary>
     /// <remarks>
-    /// Validators must derive from <see cref="BindingValidator{T}"/>.
+    /// 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"/>.
+    /// Initializes an instance of <see cref="CommandParameterAttribute" />.
     /// </summary>
     public CommandParameterAttribute(int order)
     {

CliFx/CliApplication.cs

@@ -34,7 +34,7 @@ public class CliApplication
     private readonly CommandBinder _commandBinder;
 
     /// <summary>
-    /// Initializes an instance of <see cref="CliApplication"/>.
+    /// Initializes an instance of <see cref="CliApplication" />.
     /// </summary>
     public CliApplication(
         ApplicationMetadata metadata,

CliFx/CliApplicationBuilder.cs

@@ -12,7 +12,7 @@ using CliFx.Utils.Extensions;
 namespace CliFx;
 
 /// <summary>
-/// Builder for <see cref="CliApplication"/>.
+/// Builder for <see cref="CliApplication" />.
 /// </summary>
 public partial class CliApplicationBuilder
 {
@@ -58,8 +58,8 @@ public partial class CliApplicationBuilder
     /// Adds commands from the specified assembly to the application.
     /// </summary>
     /// <remarks>
-    /// This method looks for public non-abstract classes that implement <see cref="ICommand"/>
+    /// This method looks for public non-abstract classes that implement <see cref="ICommand" />
-    /// and are annotated by <see cref="CommandAttribute"/>.
+    /// and are annotated by <see cref="CommandAttribute" />.
     /// </remarks>
     public CliApplicationBuilder AddCommandsFrom(Assembly commandAssembly)
     {
@@ -73,8 +73,8 @@ public partial class CliApplicationBuilder
     /// Adds commands from the specified assemblies to the application.
     /// </summary>
     /// <remarks>
-    /// This method looks for public non-abstract classes that implement <see cref="ICommand"/>
+    /// This method looks for public non-abstract classes that implement <see cref="ICommand" />
-    /// and are annotated by <see cref="CommandAttribute"/>.
+    /// and are annotated by <see cref="CommandAttribute" />.
     /// </remarks>
     public CliApplicationBuilder AddCommandsFrom(IEnumerable<Assembly> commandAssemblies)
     {
@@ -88,8 +88,8 @@ public partial class CliApplicationBuilder
     /// Adds commands from the calling assembly to the application.
     /// </summary>
     /// <remarks>
-    /// This method looks for public non-abstract classes that implement <see cref="ICommand"/>
+    /// This method looks for public non-abstract classes that implement <see cref="ICommand" />
-    /// and are annotated by <see cref="CommandAttribute"/>.
+    /// and are annotated by <see cref="CommandAttribute" />.
     /// </remarks>
     public CliApplicationBuilder AddCommandsFromThisAssembly() => AddCommandsFrom(Assembly.GetCallingAssembly());
 
@@ -159,7 +159,7 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Configures the application to use the specified implementation of <see cref="IConsole"/>.
+    /// Configures the application to use the specified implementation of <see cref="IConsole" />.
     /// </summary>
     public CliApplicationBuilder UseConsole(IConsole console)
     {
@@ -168,7 +168,7 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Configures the application to use the specified implementation of <see cref="ITypeActivator"/>.
+    /// Configures the application to use the specified implementation of <see cref="ITypeActivator" />.
     /// </summary>
     public CliApplicationBuilder UseTypeActivator(ITypeActivator typeActivator)
     {
@@ -189,7 +189,7 @@ public partial class CliApplicationBuilder
         UseTypeActivator(serviceProvider.GetService);
 
     /// <summary>
-    /// Creates a configured instance of <see cref="CliApplication"/>.
+    /// Creates a configured instance of <see cref="CliApplication" />.
     /// </summary>
     public CliApplication Build()
     {

CliFx/CliFx.csproj

@@ -2,9 +2,12 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.1;netstandard2.0</TargetFrameworks>
+    <IsPackable>true</IsPackable>
+  </PropertyGroup>
+
+  <PropertyGroup>
     <Authors>$(Company)</Authors>
     <Description>Declarative framework for building command line applications</Description>
-    <IsPackable>true</IsPackable>
     <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>
@@ -24,16 +27,17 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="all" />
-    <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="all" />
+    <PackageReference Include="Nullable" Version="1.3.1" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />
   </ItemGroup>
 
-  <!-- Pack the analyzer assembly inside the package -->
+  <!-- Embed the analyzer inside the package -->
   <ItemGroup>
     <ProjectReference Include="../CliFx.Analyzers/CliFx.Analyzers.csproj" ReferenceOutputAssembly="false" OutputItemType="analyzer" />
+    <None Include="../CliFx.Analyzers/bin/$(Configuration)/netstandard2.0/CliFx.Analyzers.deps.json" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
     <None Include="../CliFx.Analyzers/bin/$(Configuration)/netstandard2.0/CliFx.Analyzers.dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
     <None Include="../CliFx.Analyzers/bin/$(Configuration)/netstandard2.0/System.Buffers.dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
     <None Include="../CliFx.Analyzers/bin/$(Configuration)/netstandard2.0/System.Collections.Immutable.dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />

CliFx/CommandBinder.cs

@@ -99,11 +99,11 @@ internal class CommandBinder
         }
 
         throw CliFxException.InternalError(
-            $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has an unsupported underlying property type." +
+            $"""
-            Environment.NewLine +
+            {memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has an unsupported underlying property type.
-            $"There is no known way to convert a string value into an instance of type `{targetType.FullName}`." +
+            There is no known way to convert a string value into an instance of type `{targetType.FullName}`
-            Environment.NewLine +
+            To fix this, either change the property to use a supported type or configure a custom converter.
-            "To fix this, either change the property to use a supported type or configure a custom converter."
+            """
         );
     }
 
@@ -133,11 +133,11 @@ internal class CommandBinder
         }
 
         throw CliFxException.InternalError(
-            $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has an unsupported underlying property type." +
+            $"""
-            Environment.NewLine +
+            {memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has an unsupported underlying property type.
-            $"There is no known way to convert an array of `{targetElementType.FullName}` into an instance of type `{targetEnumerableType.FullName}`." +
+            There is no known way to convert an array of `{targetElementType.FullName}` into an instance of type `{targetEnumerableType.FullName}`.
-            Environment.NewLine +
+            To fix this, change the property to use a type which can be assigned from an array or a type that has a constructor which accepts an array.
-            "To fix this, change the property to use a type which can be assigned from an array or a type that has a constructor which accepts an array."
+            """
         );
     }
 
@@ -169,20 +169,21 @@ internal class CommandBinder
                 : ex.Message;
 
             throw CliFxException.UserError(
-                $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} cannot be set from the provided argument(s):" +
+                $"""
-                Environment.NewLine +
+                {memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} cannot be set from the provided argument(s):
-                rawValues.Select(v => '<' + v + '>').JoinToString(" ") +
+                {rawValues.Select(v => '<' + v + '>').JoinToString(" ")}
-                Environment.NewLine +
+                Error: {errorMessage}
-                $"Error: {errorMessage}",
+                """,
                 ex
             );
         }
 
         // Mismatch (scalar but too many values)
         throw CliFxException.UserError(
-            $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} expects a single argument, but provided with multiple:" +
+            $"""
-            Environment.NewLine +
+            {memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} expects a single argument, but provided with multiple:
-            rawValues.Select(v => '<' + v + '>').JoinToString(" ")
+            {rawValues.Select(v => '<' + v + '>').JoinToString(" ")}
+            """
         );
     }
 
@@ -202,11 +203,11 @@ internal class CommandBinder
         if (errors.Any())
         {
             throw CliFxException.UserError(
-                $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has been provided with an invalid value." +
+                $"""
-                Environment.NewLine +
+                {memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} has been provided with an invalid value.
-                "Error(s):" +
+                Error(s):
-                Environment.NewLine +
+                {errors.Select(e => "- " + e.Message).JoinToString(Environment.NewLine)}
-                errors.Select(e => "- " + e.Message).JoinToString(Environment.NewLine)
+                """
             );
         }
     }
@@ -264,22 +265,20 @@ internal class CommandBinder
         if (remainingParameterInputs.Any())
         {
             throw CliFxException.UserError(
-                "Unexpected parameter(s):" +
+                $"""
-                Environment.NewLine +
+                Unexpected parameter(s):
-                remainingParameterInputs
+                {remainingParameterInputs.Select(p => p.GetFormattedIdentifier()).JoinToString(" ")}
-                    .Select(p => p.GetFormattedIdentifier())
+                """
-                    .JoinToString(" ")
             );
         }
 
         if (remainingRequiredParameterSchemas.Any())
         {
             throw CliFxException.UserError(
-                "Missing required parameter(s):" +
+                $"""
-                Environment.NewLine +
+                Missing required parameter(s):
-                remainingRequiredParameterSchemas
+                {remainingRequiredParameterSchemas.Select(p => p.GetFormattedIdentifier()).JoinToString(" ")}
-                    .Select(p => p.GetFormattedIdentifier())
+                """
-                    .JoinToString(" ")
             );
         }
     }
@@ -337,22 +336,20 @@ internal class CommandBinder
         if (remainingOptionInputs.Any())
         {
             throw CliFxException.UserError(
-                "Unrecognized option(s):" +
+                $"""
-                Environment.NewLine +
+                Unrecognized option(s):
-                remainingOptionInputs
+                {remainingOptionInputs.Select(o => o.GetFormattedIdentifier()).JoinToString(", ")}
-                    .Select(o => o.GetFormattedIdentifier())
+                """
-                    .JoinToString(", ")
             );
         }
 
         if (remainingRequiredOptionSchemas.Any())
         {
             throw CliFxException.UserError(
-                "Missing required option(s):" +
+                $"""
-                Environment.NewLine +
+                Missing required option(s):
-                remainingRequiredOptionSchemas
+                {remainingRequiredOptionSchemas.Select(o => o.GetFormattedIdentifier()).JoinToString(", ")}
-                    .Select(o => o.GetFormattedIdentifier())
+                """
-                    .JoinToString(", ")
             );
         }
     }

CliFx/Exceptions/CliFxException.cs

@@ -24,7 +24,7 @@ public partial class CliFxException : Exception
     public bool ShowHelp { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="CliFxException"/>.
+    /// Initializes an instance of <see cref="CliFxException" />.
     /// </summary>
     public CliFxException(
         string message,

CliFx/Exceptions/CommandException.cs

@@ -9,7 +9,7 @@ namespace CliFx.Exceptions;
 public class CommandException : CliFxException
 {
     /// <summary>
-    /// Initializes an instance of <see cref="CommandException"/>.
+    /// Initializes an instance of <see cref="CommandException" />.
     /// </summary>
     public CommandException(
         string message,

CliFx/Extensibility/BindingValidationError.cs

@@ -11,7 +11,7 @@ public class BindingValidationError
     public string Message { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="BindingValidationError"/>.
+    /// Initializes an instance of <see cref="BindingValidationError" />.
     /// </summary>
     public BindingValidationError(string message) => Message = message;
 }

CliFx/Extensibility/BindingValidator.cs

@@ -26,7 +26,7 @@ public abstract class BindingValidator<T> : IBindingValidator
     /// Returns null if validation is successful, or an error in case of failure.
     /// </summary>
     /// <remarks>
-    /// You can use the utility methods <see cref="Ok"/> and <see cref="Error"/> to
+    /// You can use the utility methods <see cref="Ok" /> and <see cref="Error" /> to
     /// create an appropriate result.
     /// </remarks>
     public abstract BindingValidationError? Validate(T? value);

CliFx/ICommand.cs

@@ -9,7 +9,7 @@ namespace CliFx;
 public interface ICommand
 {
     /// <summary>
-    /// Executes the command using the specified implementation of <see cref="IConsole"/>.
+    /// Executes the command using the specified implementation of <see cref="IConsole" />.
     /// </summary>
     /// <remarks>
     /// If the execution of the command is not asynchronous, simply end the method with

CliFx/Infrastructure/ConsoleReader.cs

@@ -7,7 +7,7 @@ using System.Threading.Tasks;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implements a <see cref="TextReader"/> for reading characters from a console stream.
+/// Implements a <see cref="TextReader" /> for reading characters from a console stream.
 /// </summary>
 // Both the underlying stream AND the stream reader must be synchronized!
 // https://github.com/Tyrrrz/CliFx/issues/123
@@ -19,7 +19,7 @@ public partial class ConsoleReader : StreamReader
     public IConsole Console { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ConsoleReader"/>.
+    /// Initializes an instance of <see cref="ConsoleReader" />.
     /// </summary>
     public ConsoleReader(IConsole console, Stream stream, Encoding encoding)
         : base(stream, encoding, false, 4096)
@@ -28,7 +28,7 @@ public partial class ConsoleReader : StreamReader
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ConsoleReader"/>.
+    /// Initializes an instance of <see cref="ConsoleReader" />.
     /// </summary>
     public ConsoleReader(IConsole console, Stream stream)
         : this(console, stream, System.Console.InputEncoding)

CliFx/Infrastructure/ConsoleWriter.cs

@@ -8,7 +8,7 @@ using CliFx.Utils;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implements a <see cref="TextWriter"/> for writing characters to a console stream.
+/// Implements a <see cref="TextWriter" /> for writing characters to a console stream.
 /// </summary>
 // Both the underlying stream AND the stream writer must be synchronized!
 // https://github.com/Tyrrrz/CliFx/issues/123
@@ -20,7 +20,7 @@ public partial class ConsoleWriter : StreamWriter
     public IConsole Console { get; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ConsoleWriter"/>.
+    /// Initializes an instance of <see cref="ConsoleWriter" />.
     /// </summary>
     public ConsoleWriter(IConsole console, Stream stream, Encoding encoding)
         : base(stream, encoding.WithoutPreamble(), 256)
@@ -29,7 +29,7 @@ public partial class ConsoleWriter : StreamWriter
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="ConsoleWriter"/>.
+    /// Initializes an instance of <see cref="ConsoleWriter" />.
     /// </summary>
     public ConsoleWriter(IConsole console, Stream stream)
         : this(console, stream, System.Console.OutputEncoding)

CliFx/Infrastructure/DefaultTypeActivator.cs

@@ -4,7 +4,7 @@ using CliFx.Exceptions;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="ITypeActivator"/> that instantiates an object
+/// Implementation of <see cref="ITypeActivator" /> that instantiates an object
 /// by using its parameterless constructor.
 /// </summary>
 public class DefaultTypeActivator : ITypeActivator
@@ -20,11 +20,11 @@ public class DefaultTypeActivator : ITypeActivator
         catch (MemberAccessException ex)
         {
             throw CliFxException.InternalError(
-                $"Failed to create an instance of type `{type.FullName}`, could not access the constructor." +
+                $"""
-                Environment.NewLine +
+                Failed to create an instance of type `{type.FullName}`, could not access the constructor.
-                "Default type activator is only capable of instantiating a type if it has a public parameterless constructor." +
+                Default type activator is only capable of instantiating a type if it has a public parameterless constructor.
-                Environment.NewLine +
+                To fix this, either add a parameterless constructor to the type or configure a custom activator for the application.
-                "To fix this, either add a parameterless constructor to the type or configure a custom activator for the application.",
+                """,
                 ex
             );
         }

CliFx/Infrastructure/DelegateTypeActivator.cs

@@ -4,7 +4,7 @@ using CliFx.Exceptions;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="ITypeActivator"/> that instantiates an object
+/// Implementation of <see cref="ITypeActivator" /> that instantiates an object
 /// by using a predefined function.
 /// </summary>
 public class DelegateTypeActivator : ITypeActivator
@@ -12,7 +12,7 @@ public class DelegateTypeActivator : ITypeActivator
     private readonly Func<Type, object> _func;
 
     /// <summary>
-    /// Initializes an instance of <see cref="DelegateTypeActivator"/>.
+    /// Initializes an instance of <see cref="DelegateTypeActivator" />.
     /// </summary>
     public DelegateTypeActivator(Func<Type, object> func) => _func = func;
 
@@ -24,11 +24,11 @@ public class DelegateTypeActivator : ITypeActivator
         if (instance is null)
         {
             throw CliFxException.InternalError(
-                $"Failed to create an instance of type `{type.FullName}`, received <null> instead." +
+                $"""
-                Environment.NewLine +
+                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>." +
+                To fix this, ensure that the provided type activator is configured correctly, as it's not expected to return <null>.
-                Environment.NewLine +
+                If you are relying on a dependency container, this error may indicate that the specified type has not been registered.
-                "If you are relying on a dependency container, this error may indicate that the specified type has not been registered."
+                """
             );
         }
 

CliFx/Infrastructure/FakeConsole.cs

@@ -6,7 +6,7 @@ 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.
 /// </summary>
 /// <remarks>
@@ -54,7 +54,7 @@ public class FakeConsole : IConsole, IDisposable
     public int CursorTop { get; set; }
 
     /// <summary>
-    /// Initializes an instance of <see cref="FakeConsole"/>.
+    /// Initializes an instance of <see cref="FakeConsole" />.
     /// </summary>
     public FakeConsole(Stream? input = null, Stream? output = null, Stream? error = null)
     {
@@ -73,7 +73,7 @@ public class FakeConsole : IConsole, IDisposable
             );
 
     /// <summary>
-    /// Enqueues a simulated key press, which can then be read by calling <see cref="ReadKey"/>.
+    /// Enqueues a simulated key press, which can then be read by calling <see cref="ReadKey" />.
     /// </summary>
     public void EnqueueKey(ConsoleKeyInfo key) => _keys.Enqueue(key);
 
@@ -96,7 +96,7 @@ public class FakeConsole : IConsole, IDisposable
     /// Sends a cancellation signal to the currently executing command.
     /// </summary>
     /// <remarks>
-    /// If the command is not cancellation-aware (i.e. it doesn't call <see cref="IConsole.RegisterCancellationHandler"/>),
+    /// If the command is not cancellation-aware (i.e. it doesn't call <see cref="IConsole.RegisterCancellationHandler" />),
     /// this method will not have any effect.
     /// </remarks>
     public void RequestCancellation(TimeSpan? delay = null)

CliFx/Infrastructure/FakeInMemoryConsole.cs

@@ -3,7 +3,7 @@
 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 backed by in-memory stores.
 /// </summary>
 /// <remarks>
@@ -24,7 +24,7 @@ public class FakeInMemoryConsole : FakeConsole
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="FakeInMemoryConsole"/>.
+    /// Initializes an instance of <see cref="FakeInMemoryConsole" />.
     /// </summary>
     public FakeInMemoryConsole()
         : this(new MemoryStream(), new MemoryStream(), new MemoryStream())

CliFx/Infrastructure/IConsole.cs

@@ -105,12 +105,12 @@ public interface IConsole
 }
 
 /// <summary>
-/// Extensions for <see cref="IConsole"/>.
+/// Extensions for <see cref="IConsole" />.
 /// </summary>
 public static class ConsoleExtensions
 {
     /// <summary>
-    /// Sets the specified foreground color and returns an <see cref="IDisposable"/>
+    /// Sets the specified foreground color and returns an <see cref="IDisposable" />
     /// that will reset the color back to its previous value upon disposal.
     /// </summary>
     public static IDisposable WithForegroundColor(this IConsole console, ConsoleColor foregroundColor)
@@ -122,7 +122,7 @@ public static class ConsoleExtensions
     }
 
     /// <summary>
-    /// Sets the specified background color and returns an <see cref="IDisposable"/>
+    /// Sets the specified background color and returns an <see cref="IDisposable" />
     /// that will reset the color back to its previous value upon disposal.
     /// </summary>
     public static IDisposable WithBackgroundColor(this IConsole console, ConsoleColor backgroundColor)
@@ -134,7 +134,7 @@ public static class ConsoleExtensions
     }
 
     /// <summary>
-    /// Sets the specified foreground and background colors and returns an <see cref="IDisposable"/>
+    /// Sets the specified foreground and background colors and returns an <see cref="IDisposable" />
     /// that will reset the colors back to their previous values upon disposal.
     /// </summary>
     public static IDisposable WithColors(

CliFx/Infrastructure/SystemConsole.cs

@@ -4,7 +4,7 @@ using System.Threading;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="IConsole"/> that represents the real system console.
+/// Implementation of <see cref="IConsole" /> that represents the real system console.
 /// </summary>
 public class SystemConsole : IConsole, IDisposable
 {
@@ -71,7 +71,7 @@ public class SystemConsole : IConsole, IDisposable
     }
 
     /// <summary>
-    /// Initializes an instance of <see cref="SystemConsole"/>.
+    /// Initializes an instance of <see cref="SystemConsole" />.
     /// </summary>
     public SystemConsole()
     {

CliFx/Input/CommandInput.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using CliFx.Utils.Extensions;
 
 namespace CliFx.Input;

CliFx/Schema/CommandSchema.cs

@@ -129,15 +129,13 @@ internal partial class CommandSchema
         if (schema is null)
         {
             throw CliFxException.InternalError(
-                $"Type `{type.FullName}` is not a valid command type." +
+                $"""
-                Environment.NewLine +
+                Type `{type.FullName}` is not a valid command type.
-                "In order to be a valid command type, it must:" +
+                In order to be a valid command type, it must:
-                Environment.NewLine +
+                - Implement `{typeof(ICommand).FullName}`
-                $"- Implement `{typeof(ICommand).FullName}`" +
+                - Be annotated with `{typeof(CommandAttribute).FullName}`
-                Environment.NewLine +
+                - Not be an abstract class
-                $"- Be annotated with `{typeof(CommandAttribute).FullName}`" +
+                """
-                Environment.NewLine +
-                "- Not be an abstract class"
             );
         }
 

CliFx/Schema/OptionSchema.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Reflection;
 using System.Text;
 using CliFx.Attributes;
+using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
@@ -101,6 +102,7 @@ internal partial class OptionSchema
         // The user may mistakenly specify dashes, thinking it's required, so trim them
         var name = attribute.Name?.TrimStart('-').Trim();
         var environmentVariable = attribute.EnvironmentVariable?.Trim();
+        var isRequired = attribute.IsRequired || property.IsRequired();
         var description = attribute.Description?.Trim();
 
         return new OptionSchema(
@@ -108,7 +110,7 @@ internal partial class OptionSchema
             name,
             attribute.ShortName,
             environmentVariable,
-            attribute.IsRequired,
+            isRequired,
             description,
             attribute.Converter,
             attribute.Validators

CliFx/Schema/ParameterSchema.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Reflection;
 using CliFx.Attributes;
+using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
@@ -53,13 +54,14 @@ internal partial class ParameterSchema
             return null;
 
         var name = attribute.Name?.Trim() ?? property.Name.ToLowerInvariant();
+        var isRequired = attribute.IsRequired || property.IsRequired();
         var description = attribute.Description?.Trim();
 
         return new ParameterSchema(
             new BindablePropertyDescriptor(property),
             attribute.Order,
             name,
-            attribute.IsRequired,
+            isRequired,
             description,
             attribute.Converter,
             attribute.Validators

CliFx/Utils/Extensions/CollectionExtensions.cs

@@ -1,4 +1,5 @@
-using System.Collections;
+using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -37,4 +38,14 @@ internal static class CollectionExtensions
         dictionary
             .Cast<DictionaryEntry>()
             .ToDictionary(entry => (TKey) entry.Key, entry => (TValue) entry.Value, comparer);
+
+    public static Array ToNonGenericArray<T>(this IEnumerable<T> source, Type elementType)
+    {
+        var sourceAsCollection = source as ICollection ?? source.ToArray();
+
+        var array = Array.CreateInstance(elementType, sourceAsCollection.Count);
+        sourceAsCollection.CopyTo(array, 0);
+
+        return array;
+    }
 }

CliFx/Utils/Extensions/PropertyExtensions.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Linq;
+using System.Reflection;
+
+namespace CliFx.Utils.Extensions;
+
+internal static class PropertyExtensions
+{
+    public static bool IsRequired(this PropertyInfo propertyInfo) =>
+        // Match attribute by name to avoid depending on .NET 7.0+ and to allow polyfilling
+        propertyInfo.GetCustomAttributes().Any(a =>
+            string.Equals(
+                a.GetType().FullName,
+                "System.Runtime.CompilerServices.RequiredMemberAttribute",
+                StringComparison.Ordinal
+            )
+        );
+}

CliFx/Utils/Extensions/TypeExtensions.cs

@@ -11,7 +11,8 @@ internal static class TypeExtensions
     public static bool Implements(this Type type, Type interfaceType) =>
         type.GetInterfaces().Contains(interfaceType);
 
-    public static Type? TryGetNullableUnderlyingType(this Type type) => Nullable.GetUnderlyingType(type);
+    public static Type? TryGetNullableUnderlyingType(this Type type) =>
+        Nullable.GetUnderlyingType(type);
 
     public static Type? TryGetEnumerableUnderlyingType(this Type type)
     {
@@ -44,16 +45,6 @@ internal static class TypeExtensions
         );
     }
 
-    public static Array ToNonGenericArray<T>(this IEnumerable<T> source, Type elementType)
-    {
-        var sourceAsCollection = source as ICollection ?? source.ToArray();
-
-        var array = Array.CreateInstance(elementType, sourceAsCollection.Count);
-        sourceAsCollection.CopyTo(array, 0);
-
-        return array;
-    }
-
     public static bool IsToStringOverriden(this Type type)
     {
         var toStringMethod = type.GetMethod(nameof(ToString), Type.EmptyTypes);

CliFx/Utils/StackFrame.cs

@@ -96,9 +96,10 @@ internal partial class StackFrame
             // If parsing fails, we include the original stacktrace in the
             // exception so that it's shown to the user.
             throw new FormatException(
-                "Could not parse stacktrace:" +
+                $"""
-                Environment.NewLine +
+                Could not parse stacktrace:
-                stackTrace
+                {stackTrace}
+                """
             );
         }
 

Directory.Build.props

@@ -1,12 +1,13 @@
 <Project>
 
   <PropertyGroup>
-    <Version>2.3</Version>
+    <Version>2.3.1</Version>
     <Company>Tyrrrz</Company>
     <Copyright>Copyright (C) Oleksii Holub</Copyright>
     <LangVersion>latest</LangVersion>
     <Nullable>enable</Nullable>
     <WarningsAsErrors>nullable</WarningsAsErrors>
+    <CheckEolTargetFramework>false</CheckEolTargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 

Readme.md

@@ -9,7 +9,7 @@
 [![Donate](https://img.shields.io/badge/donate-$$$-8a2be2.svg)](https://tyrrrz.me/donate)
 [![Fuck Russia](https://img.shields.io/badge/fuck-russia-e4181c.svg?labelColor=000000)](https://twitter.com/tyrrrz/status/1495972128977571848)
 
-> 🟢 **Project status**: active<sup>[[?]](https://github.com/Tyrrrz/.github/blob/master/docs/project-status.md)</sup>
+> 🟡 **Project status**: maintenance mode<sup>[[?]](https://github.com/Tyrrrz/.github/blob/master/docs/project-status.md)</sup>
 
 **CliFx** is a simple to use, yet powerful framework for building command line applications.
 Its primary goal is to completely take over the user input layer, allowing you to forget about infrastructural concerns and instead focus on writing your application.
@@ -144,7 +144,7 @@ public class LogCommand : ICommand
 {
     // Order: 0
     [CommandParameter(0, Description = "Value whose logarithm is to be found.")]
-    public double Value { get; init; }
+    public required double Value { get; init; }
 
     // Name: --base
     // Short name: -b
@@ -212,14 +212,14 @@ OPTIONS
 Overall, parameters and options are both used to consume input from the command line, but they differ in a few important ways:
 
 |                    | Parameter                                                                      | Option                                                                                               |
-|--------------------|--------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------|
+| ------------------ | ------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------- |
 | **Identification** | Positional (by relative order).                                                | Nominal (by name or short name).                                                                     |
 | **Requiredness**   | Required by default. Only the last parameter can be configured to be optional. | Optional by default. Any option can be configured to be required without limitations.                |
 | **Arity**          | Only the last parameter can be bound to a non-scalar property (i.e. an array). | Any option can be bound to a non-scalar property without limitations.                                |
 | **Fallback**       | —                                                                              | Can be configured to use an environment variable as fallback if the value isn't explicitly provided. |
 
 As a general guideline, use parameters for required inputs that the command can't function without.
-Use options for all other non-required inputs or when specifying the name explicitly makes the usage clearer.
+Use options for all other non-required inputs, or when specifying the name explicitly makes the usage clearer.
 
 ### Argument syntax
 
@@ -382,8 +382,8 @@ If the user does not provide value for such option through command line argument
 [Command]
 public class AuthCommand : ICommand
 {
-    [CommandOption("token", IsRequired = true, EnvironmentVariable = "AUTH_TOKEN")]
+    [CommandOption("token", EnvironmentVariable = "AUTH_TOKEN")]
-    public string AuthToken { get; init; }
+    public required string AuthToken { get; init; }
 
     public ValueTask ExecuteAsync(IConsole console)
     {
@@ -403,7 +403,7 @@ test
 ```
 
 Environment variables can be configured for options of non-scalar types (arrays, lists, etc.) as well.
-In such case, the values of the environment variable will be split by `Path.PathSeparator` (`;` on Windows, `:` on Linux).
+In such case, the values of the environment variable will be split by `Path.PathSeparator` (`;` on Windows, `:` on Unix systems).
 
 ### Multiple commands
 
@@ -488,7 +488,7 @@ You can run `dotnet myapp.dll cmd1 [command] --help` to show help on a specific
 
 > **Note**:
 > Defining a default (unnamed) command is not required.
-> If it's absent, running the application without specifying a command will just show the root level help text.
+> If it's absent, running the application without specifying a command will just show the root-level help text.
 
 ### Reporting errors
 
@@ -499,11 +499,11 @@ This special exception can be used to print an error message to the console, ret
 [Command]
 public class DivideCommand : ICommand
 {
-    [CommandOption("dividend", IsRequired = true)]
+    [CommandOption("dividend")]
-    public double Dividend { get; init; }
+    public required double Dividend { get; init; }
 
-    [CommandOption("divisor", IsRequired = true)]
+    [CommandOption("divisor")]
-    public double Divisor { get; init; }
+    public required double Divisor { get; init; }
 
     public ValueTask ExecuteAsync(IConsole console)
     {
@@ -567,12 +567,12 @@ public class CancellableCommand : ICommand
 ```
 
 > **Warning**:
-> Forceful termination of a command can only be delayed once.
+> Cancellation handler is only respected when the user sends the interrupt signal for the first time.
-> If the user issues a second interrupt signal, the process will be killed immediately without waiting for graceful cancellation.
+> If the user decides to issue the signal again, the application will terminate immediately regardless of whether the command is cancellation-aware.
 
 ### Type activation
 
-Because **CliFx** takes responsibility for the application's entire lifecycle, it needs to be capable of instantiating various user-defined types at runtime.
+Because **CliFx** takes responsibility for the application's entire lifecycle, it needs to be capable of instantiating various user-defined types at run-time.
 To facilitate that, it uses an interface called `ITypeActivator` that determines how to create a new instance of a given type.
 
 The default implementation of `ITypeActivator` only supports types that have public parameterless constructors, which is sufficient for the majority of scenarios.