Update SA1623 and SA1624 to not trigger if the summary contains an inheritdoc element

StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1623UnitTests.cs

@@ -345,5 +345,42 @@ public class TestClass
 
             await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Theory]
+        [InlineData("<inheritdoc/>")]
+        [InlineData("<inheritdoc/> XYZ")]
+        [WorkItem(3465, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3465")]
+        public async Task VerifyInheritdocInSummaryTagIsAllowedAsync(string summary)
+        {
+            var testCode = $@"
+public class TestClass
+{{
+    /// <summary>
+    /// {summary}
+    /// </summary>
+    public int TestProperty {{ get; set; }}
+}}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3465, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3465")]
+        public async Task VerifyInheritdocAfterTextStillReportsWarningAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    /// <summary>
+    /// XYZ <inheritdoc/>
+    /// </summary>
+    public int {|#0:TestProperty|} { get; set; }
+}
+";
+
+            var expected = Diagnostic(PropertySummaryDocumentationAnalyzer.SA1623Descriptor).WithLocation(0).WithArguments("Gets or sets");
+            await VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1624UnitTests.cs

@@ -156,5 +156,42 @@ public class TestClass
 
             await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Theory]
+        [InlineData("<inheritdoc/>")]
+        [InlineData("<inheritdoc/> XYZ")]
+        [WorkItem(3465, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3465")]
+        public async Task VerifyInheritdocInSummaryTagIsAllowedAsync(string summary)
+        {
+            var testCode = $@"
+public class TestClass
+{{
+    /// <summary>
+    /// {summary}
+    /// </summary>
+    public int TestProperty {{ get; private set; }}
+}}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3465, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3465")]
+        public async Task VerifyInheritdocAfterTextStillReportsWarningAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    /// <summary>
+    /// XYZ <inheritdoc/>
+    /// </summary>
+    public int {|#0:TestProperty|} { get; private set; }
+}
+";
+
+            var expected = Diagnostic(PropertySummaryDocumentationAnalyzer.SA1623Descriptor).WithLocation(0).WithArguments("Gets");
+            await VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/PropertySummaryDocumentationAnalyzer.cs

@@ -61,6 +61,18 @@ internal class PropertySummaryDocumentationAnalyzer : PropertyDocumentationBase
         /// <inheritdoc/>
         protected override void HandleXmlElement(SyntaxNodeAnalysisContext context, StyleCopSettings settings, bool needsComment, XmlNodeSyntax syntax, XElement completeDocumentation, Location diagnosticLocation)
         {
+            if (!(syntax is XmlElementSyntax summaryElement))
+            {
+                // This is reported by SA1604 or SA1606.
+                return;
+            }
+
+            if (SummaryStartsWithInheritdoc(summaryElement))
+            {
+                // Ignore nodes starting with an <inheritdoc/> tag.
+                return;
+            }
+
             var propertyDeclaration = (PropertyDeclarationSyntax)context.Node;
             var propertyType = context.SemanticModel.GetTypeInfo(propertyDeclaration.Type.StripRefFromType());
             var culture = settings.DocumentationRules.DocumentationCultureInfo;
@@ -70,7 +82,7 @@ protected override void HandleXmlElement(SyntaxNodeAnalysisContext context, Styl
             {
                 AnalyzeSummaryElement(
                     context,
-                    syntax,
+                    summaryElement,
                     diagnosticLocation,
                     propertyDeclaration,
                     resourceManager.GetString(nameof(DocumentationResources.StartingTextGetsWhether), culture),
@@ -82,7 +94,7 @@ protected override void HandleXmlElement(SyntaxNodeAnalysisContext context, Styl
             {
                 AnalyzeSummaryElement(
                     context,
-                    syntax,
+                    summaryElement,
                     diagnosticLocation,
                     propertyDeclaration,
                     resourceManager.GetString(nameof(DocumentationResources.StartingTextGets), culture),
@@ -92,7 +104,7 @@ protected override void HandleXmlElement(SyntaxNodeAnalysisContext context, Styl
             }
         }
 
-        private static void AnalyzeSummaryElement(SyntaxNodeAnalysisContext context, XmlNodeSyntax syntax, Location diagnosticLocation, PropertyDeclarationSyntax propertyDeclaration, string startingTextGets, string startingTextSets, string startingTextGetsOrSets, string startingTextReturns)
+        private static void AnalyzeSummaryElement(SyntaxNodeAnalysisContext context, XmlElementSyntax summaryElement, Location diagnosticLocation, PropertyDeclarationSyntax propertyDeclaration, string startingTextGets, string startingTextSets, string startingTextGetsOrSets, string startingTextReturns)
         {
             var diagnosticProperties = ImmutableDictionary.CreateBuilder<string, string>();
             ArrowExpressionClauseSyntax expressionBody = propertyDeclaration.ExpressionBody;
@@ -116,12 +128,6 @@ private static void AnalyzeSummaryElement(SyntaxNodeAnalysisContext context, Xml
                 }
             }
 
-            if (!(syntax is XmlElementSyntax summaryElement))
-            {
-                // This is reported by SA1604 or SA1606.
-                return;
-            }
-
             // Add a no code fix tag when the summary element is empty.
             // This will only impact SA1623, because SA1624 cannot trigger with an empty summary.
             if (summaryElement.Content.Count == 0)
@@ -284,6 +290,73 @@ private static void AnalyzeSummaryElement(SyntaxNodeAnalysisContext context, Xml
             }
         }
 
+        private static bool SummaryStartsWithInheritdoc(XmlElementSyntax summaryElement)
+        {
+            foreach (var child in summaryElement.Content)
+            {
+                var firstContent = GetFirstMeaningfulChild(child);
+                if (firstContent is null)
+                {
+                    continue;
+                }
+
+                return string.Equals(firstContent.GetName()?.ToString(), XmlCommentHelper.InheritdocXmlTag, StringComparison.Ordinal);
+            }
+
+            return false;
+        }
+
+        private static XmlNodeSyntax GetFirstMeaningfulChild(XmlNodeSyntax node)
+        {
+            switch (node)
+            {
+            case XmlTextSyntax textSyntax:
+                foreach (var token in textSyntax.TextTokens)
+                {
+                    if (!string.IsNullOrWhiteSpace(token.ValueText))
+                    {
+                        return textSyntax;
+                    }
+                }
+
+                return null;
+
+            case XmlEmptyElementSyntax emptyElement:
+                return emptyElement;
+
+            case XmlElementSyntax elementSyntax:
+                if (string.Equals(elementSyntax.StartTag?.Name?.ToString(), XmlCommentHelper.InheritdocXmlTag, StringComparison.Ordinal))
+                {
+                    return elementSyntax;
+                }
+
+                foreach (var child in elementSyntax.Content)
+                {
+                    var nested = GetFirstMeaningfulChild(child);
+                    if (nested != null)
+                    {
+                        return nested;
+                    }
+                }
+
+                return null;
+
+            case XmlCDataSectionSyntax cdataSyntax:
+                foreach (var token in cdataSyntax.TextTokens)
+                {
+                    if (!string.IsNullOrWhiteSpace(token.ValueText))
+                    {
+                        return cdataSyntax;
+                    }
+                }
+
+                return null;
+
+            default:
+                return null;
+            }
+        }
+
         private static void ReportSA1623(SyntaxNodeAnalysisContext context, Location diagnosticLocation, ImmutableDictionary<string, string>.Builder diagnosticProperties, string text, string expectedStartingText, string unexpectedStartingText1, string unexpectedStartingText2 = null, string unexpectedStartingText3 = null)
         {
             diagnosticProperties.Add(ExpectedTextKey, expectedStartingText);