Update SA1101 tests for extended property patterns

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/ReadabilityRules/SA1101CSharp10UnitTests.cs

@@ -31,5 +31,63 @@ public bool Method(Test arg)
 
             await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Fact]
+        [WorkItem(3984, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3984")]
+        public async Task TestExtendedPropertyPatternInSwitchAsync()
+        {
+            var testCode = @"public class Test
+{
+    public Test Child { get; init; }
+    public int Value { get; init; }
+
+    public int Evaluate(Test other)
+    {
+        return other switch
+        {
+            { Child.Value: > 0 } and not { Value: 0 } => 1,
+            { Child.Value: <= 0 } or ({ Value: 0 } and { Child.Value: 0 }) => 0,
+            _ => -1,
+        };
+    }
+}";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3984, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3984")]
+        public async Task TestExtendedPropertyPatternWithInstanceMemberAccessAsync()
+        {
+            var testCode = @"public class Test
+{
+    private int value;
+
+    public Test Child { get; }
+    public int Value { get; }
+
+    public bool Evaluate(Test other)
+    {
+        return other is { Child.Value: > 0 } && {|#0:value|} > 0;
+    }
+}";
+
+            var fixedCode = @"public class Test
+{
+    private int value;
+
+    public Test Child { get; }
+    public int Value { get; }
+
+    public bool Evaluate(Test other)
+    {
+        return other is { Child.Value: > 0 } && this.value > 0;
+    }
+}";
+
+            var expected = Diagnostic().WithLocation(0);
+
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

documentation/SA1101.md

@@ -27,6 +27,14 @@ By default, StyleCop disallows the use of underscores or *m_* to mark local clas
 
 A final advantage of using the 'this.' prefix is that typing *this.* will cause Visual Studio to show the IntelliSense popup, making it quick and easy for the developer to choose the class member to call.
 
+When using property patterns, including the extended property pattern syntax introduced in C# 10, the rule does not require (or allow) `this.` to qualify the properties referenced by the pattern. These expressions refer to members of the value being matched rather than the containing type. For example, no SA1101 diagnostic is reported for the following:
+
+```csharp
+if (item is { Outer.Inner: value })
+{
+}
+```
+
 ## How to fix violations
 
 To fix a violation of this rule, insert the 'this.' prefix before the call to the class member.