diff --git a/SysML2.NET.Serializer.TextualNotation.Tests/Expected/18-Use Case/18-Use Case.sysml b/SysML2.NET.Serializer.TextualNotation.Tests/Expected/18-Use Case/18-Use Case.sysml
new file mode 100644
index 00000000..8eee106b
--- /dev/null
+++ b/SysML2.NET.Serializer.TextualNotation.Tests/Expected/18-Use Case/18-Use Case.sysml	
@@ -0,0 +1,76 @@
+package '18-Use Case' {
+    part def Vehicle;
+    part def Person;
+    part def Environment;
+    part def 'Fuel Station';
+    use case 'provide transportation' {
+        subject vehicle: Vehicle;
+        actor driver: Person;
+        actor passengers: Person[0..4];
+        actor environment: Environment;
+        objective {
+            doc
+            /*
+             * Satisfy mission requirements to transport driver and passengers
+             * from starting location to ending location in conformance with
+             * the driving profile and meet the mission requirements for safety,
+             * reliability, comfort, and affordability.
+             */
+
+        }
+        :>> start {
+            doc
+            /* Mock-up of a pre-condition. */
+            assert constraint { doc /* Vehicle at starting location */ }
+        }
+        first start;
+        then include 'enter vehicle' {
+            subject;
+            actor :>> driver = 'provide transportation'::driver;
+            actor :>> passengers = 'provide transportation'::passengers;
+        }
+        then use case 'drive vehicle' {
+            include 'add fuel'[0..*] {
+                doc
+                /*
+                 * Mock-up of an extension point.
+                 * (But reference to 'add fuel' is in the wrong direction, and it doesn't
+                 * make the extension condition sufficient to trigger the behavior.)
+                 */
+
+                subject;
+                actor :>> fueler = driver;
+                :>> start {
+                    doc
+                    /* Fuel level < 10% max fuel */
+                }
+            }
+        }
+        then include 'exit vehicle' {
+            subject;
+            actor :>> driver = 'provide transportation'::driver;
+            actor :>> passengers = 'provide transportation'::passengers;
+        }
+        then done;
+        :>> done {
+            doc
+            /* Mock-up of a post-condition. */
+            assert constraint { doc /* Vehicle at ending location */ }
+        }
+    }
+    use case 'enter vehicle' {
+        subject vehicle: Vehicle;
+        actor driver: Person;
+        actor passengers: Person[0..4];
+    }
+    use case 'exit vehicle' {
+        subject vehicle: Vehicle;
+        actor driver: Person;
+        actor passengers: Person[0..4];
+    }
+    use case 'add fuel' {
+        subject vehicle: Vehicle;
+        actor fueler: Person;
+        actor 'fuel station': 'Fuel Station';
+    }
+}
diff --git a/SysML2.NET.Serializer.TextualNotation.Tests/SysML2.NET.Serializer.TextualNotation.Tests.csproj b/SysML2.NET.Serializer.TextualNotation.Tests/SysML2.NET.Serializer.TextualNotation.Tests.csproj
index 0a0f680b..080d52cc 100644
--- a/SysML2.NET.Serializer.TextualNotation.Tests/SysML2.NET.Serializer.TextualNotation.Tests.csproj
+++ b/SysML2.NET.Serializer.TextualNotation.Tests/SysML2.NET.Serializer.TextualNotation.Tests.csproj
@@ -15,6 +15,12 @@
         <IsPackable>false</IsPackable>
         <PreserveCompilationContext>true</PreserveCompilationContext>
         <SatelliteResourceLanguages>en-US</SatelliteResourceLanguages>
+        <!-- The validation corpus runs its cases in parallel and each one allocates a large POCO graph while
+             deserializing the library XMI it references. Workstation GC gives those threads a single heap to
+             contend on, which is what caps the speed-up; Server GC gives each core its own heap. Test-host
+             only - it does not affect the shipped libraries. -->
+        <ServerGarbageCollection>true</ServerGarbageCollection>
+        <ConcurrentGarbageCollection>true</ConcurrentGarbageCollection>
     </PropertyGroup>
 
     <ItemGroup>
diff --git a/SysML2.NET.Serializer.TextualNotation.Tests/Writers/TextualNotationValidationTestFixture.cs b/SysML2.NET.Serializer.TextualNotation.Tests/Writers/TextualNotationValidationTestFixture.cs
index 5ec197dd..76f49c4d 100644
--- a/SysML2.NET.Serializer.TextualNotation.Tests/Writers/TextualNotationValidationTestFixture.cs
+++ b/SysML2.NET.Serializer.TextualNotation.Tests/Writers/TextualNotationValidationTestFixture.cs
@@ -36,6 +36,7 @@ namespace SysML2.NET.Serializer.TextualNotation.Tests.Writers
     using SysML2.NET.Serializer.Xmi;
 
     [TestFixture]
+    [Parallelizable(ParallelScope.Children)]
     public class TextualNotationValidationTestFixture
     {
         /// <summary>
@@ -136,6 +137,7 @@ public void OneTimeTearDown()
         [TestCase("15-Properties-Values-Expressions", "15_19a-Materials with Properties.sysmlx")]
         [TestCase("17-Sequence Modeling", "17a-Sequence-Modeling.sysmlx")]
         [TestCase("17-Sequence Modeling", "17b-Sequence-Modeling.sysmlx")]
+        [TestCase("18-Use Case", "18-Use Case.sysmlx")]
         public async Task VerifyValidationTextualNotationXmi(string folderName, string fileName)
         {
             var loggerFactory = LoggerFactory.Create(builder =>
diff --git a/SysML2.NET.Serializer.TextualNotation/Writers/NameResolutionCache.cs b/SysML2.NET.Serializer.TextualNotation/Writers/NameResolutionCache.cs
index 0340093c..b5c81676 100644
--- a/SysML2.NET.Serializer.TextualNotation/Writers/NameResolutionCache.cs
+++ b/SysML2.NET.Serializer.TextualNotation/Writers/NameResolutionCache.cs
@@ -2346,7 +2346,7 @@ private void BuildInheritedEntries(IType type, Dictionary<string, HashSet<IEleme
                 // the names it owns resolvable.
                 pending.Enqueue((impliedGeneral, isGlobal));
 
-                AddImpliedLookupEntries(impliedGeneral, index, isGlobal);
+                AddImpliedLookupEntries(type, impliedGeneral, index, isGlobal);
             }
         }
 
@@ -2475,10 +2475,24 @@ private List<IType> QueryImpliedGeneralClosure(IType type, List<IType> declaredS
         /// <summary>
         /// Indexes, for lookup only, the members an implied general contributes.
         /// </summary>
+        /// <param name="inheritingType">The Type that reaches the general through an implied Specialization.</param>
         /// <param name="impliedGeneral">The Type reached through an implied Specialization.</param>
         /// <param name="index">The destination index.</param>
         /// <param name="isGlobal">Whether the owning scope is reached through the global namespace.</param>
-        private static void AddImpliedLookupEntries(IType impliedGeneral, Dictionary<string, HashSet<IElement>> index, bool isGlobal)
+        /// <remarks>
+        /// The contribution is filtered through <c>Type::removeRedefinedFeatures</c>, because a member the
+        /// inheriting Type REDEFINES is not one of that Type's Memberships. KerML §8.3.3.1.10 derives
+        /// <c>inheritedMemberships</c> as <c>removeRedefinedFeatures(inheritableMemberships(…))</c>, whose
+        /// second condition rejects a Membership one of whose redefined Features is a directly
+        /// <c>redefinedFeature</c> of an <c>ownedFeature</c> of the Type.
+        /// <para>Without the filter the redefined library member and the local redefinition both land in the
+        /// same simple-name bucket, so the name reads as shadowed and a reference that should be bare is
+        /// emitted fully qualified — <c>first 'provide transportation'::start</c> for <c>first start</c>.</para>
+        /// <para>The declared-supertype path needs no such filter: it reads <c>inheritedMembership</c>, which
+        /// has already applied it. Only this path bypasses that derivation, because an implied Specialization
+        /// is detached and its members have to be gathered directly.</para>
+        /// </remarks>
+        private static void AddImpliedLookupEntries(IType inheritingType, IType impliedGeneral, Dictionary<string, HashSet<IElement>> index, bool isGlobal)
         {
             if (impliedGeneral == null)
             {
@@ -2500,6 +2514,16 @@ private static void AddImpliedLookupEntries(IType impliedGeneral, Dictionary<str
                 // Same atomicity as above: an unimplemented derivation costs this general's contribution.
             }
 
+            try
+            {
+                contributed = inheritingType.RemoveRedefinedFeatures(contributed);
+            }
+            catch (NotSupportedException)
+            {
+                // Same atomicity again, and it fails safe: an unfiltered redefined member can only lengthen
+                // a name, never make one resolve to the wrong element.
+            }
+
             foreach (var member in contributed.Where(member => PassesVisibilityFilter(member, isGlobal)))
             {
                 AddLookupOnlyEntry(index, member);