Update SA1202 for default interface members

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/OrderingRules/SA1202CSharp8UnitTests.cs

@@ -5,7 +5,9 @@ namespace StyleCop.Analyzers.Test.CSharp8.OrderingRules
 {
     using System.Threading;
     using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp7.OrderingRules;
+    using StyleCop.Analyzers.Test.Helpers;
     using Xunit;
     using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
         StyleCop.Analyzers.OrderingRules.SA1202ElementsMustBeOrderedByAccess,
@@ -57,5 +59,70 @@ public async Task TestPropertiesOfInterfaceAsync()
                 NumberOfFixAllIterations = 2,
             }.RunAsync(CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Fact]
+        [WorkItem(3002, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3002")]
+        public async Task TestDefaultInterfaceMembersRequireAccessOrderingAsync()
+        {
+            var testCode = @"public interface ITest
+{
+    private void Helper() { }
+    public void {|#0:DoWork|}() { }
+}
+";
+
+            var fixedCode = @"public interface ITest
+{
+    public void DoWork() { }
+    private void Helper() { }
+}
+";
+
+            await VerifyCSharpFixAsync(testCode, Diagnostic().WithLocation(0).WithArguments("public", "private"), fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3002, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3002")]
+        public async Task TestDefaultInterfaceMembersCorrectOrderingAsync()
+        {
+            var testCode = @"public interface ITest
+{
+    public void DoWork() { }
+    private void Helper() { }
+}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3002, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3002")]
+        public async Task TestInterfaceMembersMixingImplicitAndExplicitAccessibilityAsync()
+        {
+            var testCode = @"public interface ITest
+{
+    private void Helper() { }
+    void {|#0:ImplicitPublic|}() { }
+    public void ExplicitPublic() { }
+}
+";
+
+            var fixedCode = @"public interface ITest
+{
+    void ImplicitPublic() { }
+    public void ExplicitPublic() { }
+    private void Helper() { }
+}
+";
+
+            await new CSharpTest
+            {
+                TestCode = testCode,
+                ExpectedDiagnostics = { Diagnostic().WithLocation(0).WithArguments("public", "private") },
+                FixedCode = fixedCode,
+                NumberOfIncrementalIterations = 2,
+                NumberOfFixAllIterations = 2,
+            }.RunAsync(CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

documentation/SA1202.md

@@ -40,6 +40,12 @@ rule.
 Complying with a standard ordering scheme based on access level can increase the readability and maintainability of the
 file and make it easier to identify the public interface that is being exposed from a class.
 
+### Interfaces and default interface members
+
+Default interface members (including members with implementations and static interface members) follow the same access
+ordering as class members. Within an interface, `public` members should appear before `internal`, `protected internal`,
+`protected`, `private protected`, and `private` members.
+
 ## How to fix violations
 
 To fix an instance of this violation, order the elements in the file in the order described above.