Exempt file-local types from SA1402 [resolves #3803]

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForClassCSharp11UnitTests.cs

@@ -3,9 +3,61 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForClassCSharp11UnitTests : SA1402ForClassCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local class types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalClassExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass1 {{ }}
+
+file class TestClass2 {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local static class types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalStaticClassExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass1 {{ }}
+
+file static class TestClass2 {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForDelegateCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForDelegateCSharp11UnitTests : SA1402ForDelegateCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local delegate types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalDelegateExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass {{ }}
+
+file delegate void TestDelegate();
+";
+
+            var expectedDiagnostic = Diagnostic().WithLocation(0);
+
+            await VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForEnumCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForEnumCSharp11UnitTests : SA1402ForEnumCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local enum types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalEnumExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass1 {{ }}
+
+file enum TestEnum {{ }}
+";
+
+            var expectedDiagnostic = Diagnostic().WithLocation(0);
+
+            await VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForInterfaceCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForInterfaceCSharp11UnitTests : SA1402ForInterfaceCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local interface types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalInterfaceExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public interface TestInterface1 {{ }}
+
+file interface TestInterface2 {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForRecordCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForRecordCSharp11UnitTests : SA1402ForRecordCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local record types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalRecordExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public record TestRecord1 {{ }}
+
+file record TestRecord2 {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForRecordClassCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForRecordClassCSharp11UnitTests : SA1402ForRecordClassCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local record class types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalRecordClassExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass {{ }}
+
+file record class TestRecordClass {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForRecordStructCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForRecordStructCSharp11UnitTests : SA1402ForRecordStructCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local record struct types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalRecordStructExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public class TestClass {{ }}
+
+file record struct TestRecordStruct {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/MaintainabilityRules/SA1402ForStructCSharp11UnitTests.cs

@@ -3,9 +3,37 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.MaintainabilityRules
 {
+    using System;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules;
+    using Xunit;
 
     public partial class SA1402ForStructCSharp11UnitTests : SA1402ForStructCSharp10UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1402 is not reported for file-local struct types.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3803, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3803")]
+        public async Task VerifyFileLocalStructExemptionAsync()
+        {
+            var testCode = $@"namespace TestNamespace;
+
+public struct TestStruct1 {{ }}
+
+file struct TestStruct2 {{ }}
+";
+
+            var expectedDiagnostic = this.Diagnostic().WithLocation(0);
+
+            await this.VerifyCSharpDiagnosticAsync(
+                testCode,
+                this.GetSettings(),
+                Array.Empty<DiagnosticResult>(),
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/MaintainabilityRules/SA1402FileMayOnlyContainASingleType.cs

@@ -99,7 +99,7 @@ private static void HandleSyntaxTree(SyntaxTreeAnalysisContext context, StyleCop
         private static IEnumerable<MemberDeclarationSyntax> GetTopLevelTypeDeclarations(SyntaxNode root, StyleCopSettings settings)
         {
             var allTypeDeclarations = root.DescendantNodes(descendIntoChildren: node => ContainsTopLevelTypeDeclarations(node)).OfType<MemberDeclarationSyntax>().ToList();
-            var relevantTypeDeclarations = allTypeDeclarations.Where(x => IsRelevantType(x, settings)).ToList();
+            var relevantTypeDeclarations = allTypeDeclarations.Where(x => IsRelevantType(x, settings)).Where(x => !IsFileLocalType(x)).ToList();
             return relevantTypeDeclarations;
         }
 
@@ -136,5 +136,19 @@ private static bool IsRelevantType(SyntaxNode node, StyleCopSettings settings)
 
             return isRelevant;
         }
+
+        private static bool IsFileLocalType(SyntaxNode node)
+        {
+            const SyntaxKind FileKeyword = (SyntaxKind)8449;
+
+            var modifiers = node switch
+            {
+                BaseTypeDeclarationSyntax x => x.Modifiers,
+                DelegateDeclarationSyntax x => x.Modifiers,
+                _ => default,
+            };
+
+            return modifiers.Any(FileKeyword);
+        }
     }
 }

documentation/SA1402.md

@@ -27,6 +27,8 @@ It is possible to configure which kind of types this rule should affect. By defa
 
 It is also possible to place multiple parts of the same partial type within the same file.
 
+File-local types declared using `file` modifier are exempt from this rule.
+
 ## How to fix violations
 
 To fix an instance of this violation, move each type into its own file.