Add file-scoped namespace support to SA1208

Author: ylabade

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/OrderingRules/SA1208CSharp10UnitTests.cs

@@ -3,9 +3,45 @@
 
 namespace StyleCop.Analyzers.Test.CSharp10.OrderingRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
     using StyleCop.Analyzers.Test.CSharp9.OrderingRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.OrderingRules.SA1208SystemUsingDirectivesMustBePlacedBeforeOtherUsingDirectives,
+        StyleCop.Analyzers.OrderingRules.UsingCodeFixProvider>;
 
     public class SA1208CSharp10UnitTests : SA1208CSharp9UnitTests
     {
+        [Fact]
+        public async Task TestWhenSystemUsingDirectivesAreNotOnTopInFileScopedNamespaceAsync()
+        {
+            await new CSharpTest
+            {
+                TestSources =
+                {
+                    "namespace Xyz {}",
+                    "namespace AnotherNamespace {}",
+                    @"
+namespace Test;
+
+using Xyz;
+using System;
+using System.IO;
+using AnotherNamespace;
+using System.Threading.Tasks;
+
+class A
+{
+}",
+                },
+                ExpectedDiagnostics =
+                {
+                    Diagnostic().WithLocation("/0/Test2.cs", 5, 1).WithArguments("System", "Xyz"),
+                    Diagnostic().WithLocation("/0/Test2.cs", 6, 1).WithArguments("System.IO", "Xyz"),
+                    Diagnostic().WithLocation("/0/Test2.cs", 8, 1).WithArguments("System.Threading.Tasks", "Xyz"),
+                },
+            }.RunAsync(CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/OrderingRules/SA1208SystemUsingDirectivesMustBePlacedBeforeOtherUsingDirectives.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.OrderingRules
     using Microsoft.CodeAnalysis.CSharp.Syntax;
     using Microsoft.CodeAnalysis.Diagnostics;
     using StyleCop.Analyzers.Helpers;
+    using StyleCop.Analyzers.Lightup;
     using StyleCop.Analyzers.Settings.ObjectModel;
 
     /// <summary>
@@ -40,6 +41,7 @@ internal class SA1208SystemUsingDirectivesMustBePlacedBeforeOtherUsingDirectives
 
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> CompilationUnitAction = HandleCompilationUnit;
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> NamespaceDeclarationAction = HandleNamespaceDeclaration;
+        private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> FileScopedNamespaceDeclarationAction = HandleFileScopedNamespaceDeclaration;
 
         /// <inheritdoc/>
         public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } =
@@ -53,6 +55,7 @@ public override void Initialize(AnalysisContext context)
 
             context.RegisterSyntaxNodeAction(CompilationUnitAction, SyntaxKind.CompilationUnit);
             context.RegisterSyntaxNodeAction(NamespaceDeclarationAction, SyntaxKind.NamespaceDeclaration);
+            context.RegisterSyntaxNodeAction(FileScopedNamespaceDeclarationAction, SyntaxKindEx.FileScopedNamespaceDeclaration);
         }
 
         private static void HandleCompilationUnit(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
@@ -77,9 +80,19 @@ private static void HandleNamespaceDeclaration(SyntaxNodeAnalysisContext context
             }
 
             var namespaceDeclaration = (NamespaceDeclarationSyntax)context.Node;
-
             var usings = namespaceDeclaration.Usings;
+            ProcessUsingsAndReportDiagnostic(usings, context);
+        }
+
+        private static void HandleFileScopedNamespaceDeclaration(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
+        {
+            if (!settings.OrderingRules.SystemUsingDirectivesFirst)
+            {
+                return;
+            }
 
+            var namespaceDeclaration = (FileScopedNamespaceDeclarationSyntaxWrapper)context.Node;
+            var usings = namespaceDeclaration.Usings;
             ProcessUsingsAndReportDiagnostic(usings, context);
         }