diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1646UnitTests.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1646UnitTests.cs
new file mode 100644
index 000000000..37bbcb7af
--- /dev/null
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1646UnitTests.cs
@@ -0,0 +1,31 @@
+namespace StyleCop.Analyzers.Test.DocumentationRules
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.Diagnostics;
+    using StyleCop.Analyzers.DocumentationRules;
+    using TestHelper;
+    using Xunit;
+
+    /// <summary>
+    /// This class contains unit tests for <see cref="SA1646IncludedDocumentationXPathDoesNotExist"/>.
+    /// </summary>
+    public class SA1646UnitTests : DiagnosticVerifier
+    {
+        [Fact]
+        public void TestDisabledByDefaultAndNotConfigurable()
+        {
+            var analyzer = this.GetCSharpDiagnosticAnalyzers().Single();
+            Assert.Equal(1, analyzer.SupportedDiagnostics.Length);
+            Assert.False(analyzer.SupportedDiagnostics[0].IsEnabledByDefault);
+            Assert.Contains(WellKnownDiagnosticTags.NotConfigurable, analyzer.SupportedDiagnostics[0].CustomTags);
+        }
+
+        /// <inheritdoc/>
+        protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
+        {
+            yield return new SA1646IncludedDocumentationXPathDoesNotExist();
+        }
+    }
+}
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj b/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
index 854690d1f..b32d88bdf 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
@@ -153,6 +153,7 @@
     <Compile Include="DocumentationRules\SA1642UnitTests.cs" />
     <Compile Include="DocumentationRules\SA1643UnitTests.cs" />
     <Compile Include="DocumentationRules\SA1645UnitTests.cs" />
+    <Compile Include="DocumentationRules\SA1646UnitTests.cs" />
     <Compile Include="DocumentationRules\SA1648UnitTests.cs" />
     <Compile Include="DocumentationRules\SA1650UnitTests.cs" />
     <Compile Include="DocumentationRules\SA1651UnitTests.cs" />
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/SA1646IncludedDocumentationXPathDoesNotExist.cs b/StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/SA1646IncludedDocumentationXPathDoesNotExist.cs
index cd6fe4d36..ecc3dbca1 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/SA1646IncludedDocumentationXPathDoesNotExist.cs
+++ b/StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/SA1646IncludedDocumentationXPathDoesNotExist.cs
@@ -30,6 +30,7 @@
     /// documentation file.</para>
     /// </remarks>
     [DiagnosticAnalyzer(LanguageNames.CSharp)]
+    [NoDiagnostic("This is already handled by the compiler with warning CS1589.")]
     [NoCodeFix("Cannot generate documentation")]
     public class SA1646IncludedDocumentationXPathDoesNotExist : DiagnosticAnalyzer
     {
@@ -43,7 +44,7 @@ public class SA1646IncludedDocumentationXPathDoesNotExist : DiagnosticAnalyzer
         private const string HelpLink = "http://www.stylecop.com/docs/SA1646.html";
 
         private static readonly DiagnosticDescriptor Descriptor =
-            new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, AnalyzerCategory.DocumentationRules, DiagnosticSeverity.Warning, AnalyzerConstants.DisabledNoTests, Description, HelpLink);
+            new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, AnalyzerCategory.DocumentationRules, DiagnosticSeverity.Warning, AnalyzerConstants.DisabledByDefault, Description, HelpLink, WellKnownDiagnosticTags.NotConfigurable);
 
         private static readonly ImmutableArray<DiagnosticDescriptor> SupportedDiagnosticsValue =
             ImmutableArray.Create(Descriptor);
@@ -60,7 +61,7 @@ public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
         /// <inheritdoc/>
         public override void Initialize(AnalysisContext context)
         {
-            // TODO: Implement analysis
+            // This diagnostic is not implemented (by design) in StyleCopAnalyzers.
         }
     }
 }