diff --git a/src/FluentNHibernate.Specs/Automapping/Fixtures/AutomappingSpecExtensions.cs b/src/FluentNHibernate.Specs/Automapping/Fixtures/AutomappingSpecExtensions.cs
index 3325408fc..feff2c42d 100644
--- a/src/FluentNHibernate.Specs/Automapping/Fixtures/AutomappingSpecExtensions.cs
+++ b/src/FluentNHibernate.Specs/Automapping/Fixtures/AutomappingSpecExtensions.cs
@@ -51,7 +51,7 @@ public XmlElementTester(XmlDocument doc, string path)
 
         public XmlElementTester ShouldExist()
         {
-            if (currentElement == null)
+            if (currentElement is null)
                 throw new SpecificationException(string.Format("Should exist at {0} but does not.", currentPath));
 
             return this;
@@ -59,7 +59,7 @@ public XmlElementTester ShouldExist()
 
         public XmlElementTester ShouldNotExist()
         {
-            if (currentElement != null)
+            if (currentElement is not null)
                 throw new SpecificationException(string.Format("Should not exist at {0} but does.", currentPath));
 
             return this;
diff --git a/src/FluentNHibernate.Testing/AutoMapping/TestFixtures.cs b/src/FluentNHibernate.Testing/AutoMapping/TestFixtures.cs
index 227a4f4c8..84319fd6f 100644
--- a/src/FluentNHibernate.Testing/AutoMapping/TestFixtures.cs
+++ b/src/FluentNHibernate.Testing/AutoMapping/TestFixtures.cs
@@ -330,7 +330,7 @@ public System.Type ReturnedClass
         public new bool Equals(object x, object y)
         {
             if (x == y) return true;
-            if (x == null || y == null) return false;
+            if (x is null || y is null) return false;
 
             DoubleString lhs = (DoubleString)x;
             DoubleString rhs = (DoubleString)y;
@@ -349,7 +349,7 @@ public int GetHashCode(object x)
 
         public Object DeepCopy(Object x)
         {
-            if (x == null) return null;
+            if (x is null) return null;
             DoubleString result = new DoubleString();
             DoubleString input = (DoubleString)x;
             result.s1 = input.s1;
@@ -367,7 +367,7 @@ public object NullSafeGet(DbDataReader dr, string[] names, ISessionImplementor s
             string first = (string)NHibernateUtil.String.NullSafeGet(dr, names[0], session, owner);
             string second = (string)NHibernateUtil.String.NullSafeGet(dr, names[1], session, owner);
 
-            return (first == null && second == null) ? null : new string[] { first, second };
+            return (first is null && second is null) ? null : new string[] { first, second };
         }
 
         public void NullSafeSet(DbCommand cmd, object value, int index, bool[] settable, ISessionImplementor session)
diff --git a/src/FluentNHibernate.Testing/Cfg/Db/PersistenceConfigurationTester.cs b/src/FluentNHibernate.Testing/Cfg/Db/PersistenceConfigurationTester.cs
index 351907a86..60ebcf992 100644
--- a/src/FluentNHibernate.Testing/Cfg/Db/PersistenceConfigurationTester.cs
+++ b/src/FluentNHibernate.Testing/Cfg/Db/PersistenceConfigurationTester.cs
@@ -20,7 +20,7 @@ public void SetUp()
 
     public string ValueOf(string key)
     {
-        if( _nhibConfig == null )
+        if( _nhibConfig is null )
         {
             _nhibConfig = new Configuration();
             _config.ConfigureProperties(_nhibConfig);
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ArrayConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ArrayConventionTests.cs
index d92ab376d..e8dbbcfa1 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ArrayConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ArrayConventionTests.cs
@@ -185,7 +185,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleParentClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleParentClass)) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ClassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ClassConventionTests.cs
index 42e8b2ab7..05bb3b4e2 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ClassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ClassConventionTests.cs
@@ -148,7 +148,7 @@ private void VerifyModel(Action<ClassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First();
 
         modelVerification(modelInstance);
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ComponentConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ComponentConventionTests.cs
index 03abb1816..de4d16ffd 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ComponentConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ComponentConventionTests.cs
@@ -77,7 +77,7 @@ private void VerifyModel(Action<ComponentMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = (ComponentMapping)generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(PropertyTarget)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(PropertyTarget)) is not null)
             .Classes.First()
             .Components.First(x => x is ComponentMapping);
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/CompositeIdConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/CompositeIdConventionTests.cs
index 37d02677c..990fca7fe 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/CompositeIdConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/CompositeIdConventionTests.cs
@@ -60,7 +60,7 @@ private void VerifyModel(Action<CompositeIdMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/DynamicComponentConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/DynamicComponentConventionTests.cs
index 31b58bc70..8f9fd9802 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/DynamicComponentConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/DynamicComponentConventionTests.cs
@@ -82,7 +82,7 @@ private void VerifyModel(Action<ComponentMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = (ComponentMapping)generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(PropertyTarget)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(PropertyTarget)) is not null)
             .Classes.First()
             .Components.First(x => x is ComponentMapping);
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyCollectionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyCollectionConventionTests.cs
index 5da3be14c..8013aa2c0 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyCollectionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyCollectionConventionTests.cs
@@ -257,7 +257,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyConventionTests.cs
index ccdbb5a22..a09c0f5a5 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyConventionTests.cs
@@ -239,7 +239,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyCollectionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyCollectionConventionTests.cs
index d9ae893aa..b40723ca3 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyCollectionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyCollectionConventionTests.cs
@@ -198,7 +198,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyConventionTests.cs
index 466ff8eaf..888313fcb 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasManyToManyConventionTests.cs
@@ -245,7 +245,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleInheritedClass)) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasOneConventionTests.cs
index 08e295693..7214a0aa5 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HasOneConventionTests.cs
@@ -101,7 +101,7 @@ private void VerifyModel(Action<OneToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .OneToOnes.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HibernateMappingConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HibernateMappingConventionTests.cs
index d230dc887..b4dc2ce3b 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HibernateMappingConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/HibernateMappingConventionTests.cs
@@ -84,7 +84,7 @@ private void VerifyModel(Action<HibernateMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null);
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null);
 
         modelVerification(modelInstance);
     }
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/IdConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/IdConventionTests.cs
index 6d9e18861..83f5a2e4b 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/IdConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/IdConventionTests.cs
@@ -176,7 +176,7 @@ private void VerifyModel(Action<IdMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinConventionTests.cs
index 90e034371..c55fb06e9 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinConventionTests.cs
@@ -85,7 +85,7 @@ private void VerifyModel(Action<JoinMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Joins.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinedSubclassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinedSubclassConventionTests.cs
index 938e3d894..5806866fd 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinedSubclassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/JoinedSubclassConventionTests.cs
@@ -136,7 +136,7 @@ private void VerifyModel(Action<SubclassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Subclasses.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyManyToOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyManyToOneConventionTests.cs
index 64b4f9937..1e2ab7ebb 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyManyToOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyManyToOneConventionTests.cs
@@ -70,7 +70,7 @@ private void VerifyModel(Action<KeyManyToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyPropertyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyPropertyConventionTests.cs
index b539b1b1c..eb69e37d4 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyPropertyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/KeyPropertyConventionTests.cs
@@ -53,7 +53,7 @@ private void VerifyModel(Action<KeyPropertyMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ManyToOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ManyToOneConventionTests.cs
index a9b0e5d62..909d75efd 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ManyToOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/ManyToOneConventionTests.cs
@@ -185,7 +185,7 @@ private void VerifyModel(Action<ManyToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .References.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/PropertyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/PropertyConventionTests.cs
index 7179c0b21..3b60e0dbb 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/PropertyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/PropertyConventionTests.cs
@@ -221,7 +221,7 @@ private void VerifyModel(Action<PropertyMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Properties.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/SubclassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/SubclassConventionTests.cs
index 691d2c5a7..765803615 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/SubclassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/SubclassConventionTests.cs
@@ -89,7 +89,7 @@ private void VerifyModel(Action<SubclassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Subclasses.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/VersionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/VersionConventionTests.cs
index e49a69f74..3081fdc70 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/VersionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ApplyingToModel/VersionConventionTests.cs
@@ -157,7 +157,7 @@ private void VerifyModel(Action<VersionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ValidVersionClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ValidVersionClass)) is not null)
             .Classes.First()
             .Version;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/ForeignKeyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/ForeignKeyConventionTests.cs
index 93f57dcf3..031d1735a 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/ForeignKeyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/ForeignKeyConventionTests.cs
@@ -109,7 +109,7 @@ private class TestForeignKeyConvention : ForeignKeyConvention
     {
         protected override string GetKeyName(Member property, Type type)
         {
-            return property == null ? type.Name + "!" : property.Name + "!";
+            return property is null ? type.Name + "!" : property.Name + "!";
         }
     }
 }
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ArrayConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ArrayConventionTests.cs
index e381fe9bd..641befa05 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ArrayConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ArrayConventionTests.cs
@@ -221,7 +221,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ClassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ClassConventionTests.cs
index 0e651321c..451987b82 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ClassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ClassConventionTests.cs
@@ -179,7 +179,7 @@ private void VerifyModel(Action<ClassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First();
 
         modelVerification(modelInstance);
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ComponentConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ComponentConventionTests.cs
index daa984bc9..68af0c473 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ComponentConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ComponentConventionTests.cs
@@ -97,7 +97,7 @@ private void VerifyModel(Action<ComponentMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = (ComponentMapping)generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Components.First(x => x is ComponentMapping);
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/CompositeIdConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/CompositeIdConventionTests.cs
index f61b82b9a..145021394 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/CompositeIdConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/CompositeIdConventionTests.cs
@@ -77,7 +77,7 @@ private void VerifyModel(Action<CompositeIdMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/DynamicComponentConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/DynamicComponentConventionTests.cs
index 7fe9a2294..872791eaa 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/DynamicComponentConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/DynamicComponentConventionTests.cs
@@ -103,7 +103,7 @@ private void VerifyModel(Action<ComponentMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = (ComponentMapping)generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Components.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyCollectionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyCollectionConventionTests.cs
index 98e082af4..800427eb7 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyCollectionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyCollectionConventionTests.cs
@@ -270,7 +270,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyConventionTests.cs
index 45a72be7b..587b652ee 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyConventionTests.cs
@@ -280,7 +280,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyCollectionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyCollectionConventionTests.cs
index 71c6b00ab..56f45cbb8 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyCollectionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyCollectionConventionTests.cs
@@ -250,7 +250,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyConventionTests.cs
index 7682f4760..3fa77e58e 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasManyToManyConventionTests.cs
@@ -290,7 +290,7 @@ private void VerifyModel(Action<CollectionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Collections.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasOneConventionTests.cs
index 733abff57..e66c2489a 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HasOneConventionTests.cs
@@ -127,7 +127,7 @@ private void VerifyModel(Action<OneToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .OneToOnes.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HibernateMappingConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HibernateMappingConventionTests.cs
index 59f8f118c..ebb15bbea 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HibernateMappingConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/HibernateMappingConventionTests.cs
@@ -106,7 +106,7 @@ private void VerifyModel(Action<HibernateMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null);
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null);
 
         modelVerification(modelInstance);
     }
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/IdConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/IdConventionTests.cs
index 522e6c14c..cd44db961 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/IdConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/IdConventionTests.cs
@@ -197,7 +197,7 @@ private void VerifyModel(Action<IdMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinConventionTests.cs
index 5376915e5..ed1bf88e1 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinConventionTests.cs
@@ -106,7 +106,7 @@ private void VerifyModel(Action<JoinMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Joins.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinedSubclassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinedSubclassConventionTests.cs
index 4bda3cea2..6f9eff37f 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinedSubclassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/JoinedSubclassConventionTests.cs
@@ -170,7 +170,7 @@ private void VerifyModel(Action<SubclassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Subclasses.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyManyToOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyManyToOneConventionTests.cs
index 674d9f144..faedcd3a6 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyManyToOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyManyToOneConventionTests.cs
@@ -84,7 +84,7 @@ private void VerifyModel(Action<KeyManyToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyPropertyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyPropertyConventionTests.cs
index ec51f7ff4..8cb0562af 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyPropertyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/KeyPropertyConventionTests.cs
@@ -54,7 +54,7 @@ private void VerifyModel(Action<KeyPropertyMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(ExampleClass)) is not null)
             .Classes.First()
             .Id;
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ManyToOneConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ManyToOneConventionTests.cs
index 4c3e691d2..dda9cb2fb 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ManyToOneConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/ManyToOneConventionTests.cs
@@ -221,7 +221,7 @@ private void VerifyModel(Action<ManyToOneMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .References.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/PropertyConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/PropertyConventionTests.cs
index a0e0c8ca7..565c7e827 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/PropertyConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/PropertyConventionTests.cs
@@ -277,7 +277,7 @@ private void VerifyModel(Action<PropertyMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Properties.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/SubclassConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/SubclassConventionTests.cs
index ab89ac7b6..38f014804 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/SubclassConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/SubclassConventionTests.cs
@@ -121,7 +121,7 @@ private void VerifyModel(Action<SubclassMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Subclasses.First();
 
diff --git a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/VersionConventionTests.cs b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/VersionConventionTests.cs
index 42e1ea1fe..618efe904 100644
--- a/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/VersionConventionTests.cs
+++ b/src/FluentNHibernate.Testing/ConventionsTests/OverridingFluentInterface/VersionConventionTests.cs
@@ -199,7 +199,7 @@ private void VerifyModel(Action<VersionMapping> modelVerification)
 
         var generatedModels = model.BuildMappings();
         var modelInstance = generatedModels
-            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) != null)
+            .First(x => x.Classes.FirstOrDefault(c => c.Type == mappingType) is not null)
             .Classes.First()
             .Version;
 
diff --git a/src/FluentNHibernate.Testing/DomainModel/Access/CompositeIdModel.cs b/src/FluentNHibernate.Testing/DomainModel/Access/CompositeIdModel.cs
index 76822a77e..779862077 100644
--- a/src/FluentNHibernate.Testing/DomainModel/Access/CompositeIdModel.cs
+++ b/src/FluentNHibernate.Testing/DomainModel/Access/CompositeIdModel.cs
@@ -18,6 +18,6 @@ public override bool Equals(object obj)
 
     public virtual bool Equals(CompositeIdModel other)
     {
-        return other != null && other.IdA == this.IdA && other.IdB == this.IdB;
+        return other is not null && other.IdA == this.IdA && other.IdB == this.IdB;
     }
 }
diff --git a/src/FluentNHibernate.Testing/DomainModel/Mapping/MappingTester.cs b/src/FluentNHibernate.Testing/DomainModel/Mapping/MappingTester.cs
index abface1dd..71a92e939 100644
--- a/src/FluentNHibernate.Testing/DomainModel/Mapping/MappingTester.cs
+++ b/src/FluentNHibernate.Testing/DomainModel/Mapping/MappingTester.cs
@@ -59,13 +59,13 @@ public virtual MappingTester<T> ForMapping(Action<ClassMap<T>> mappingAction)
 
     public virtual MappingTester<T> ForMapping(ClassMap<T> classMap)
     {
-        if (classMap  != null)
+        if (classMap  is not null)
             model.Add(classMap);
 
         var mappings = model.BuildMappings();
-        var foundMapping = mappings.FirstOrDefault(x => x.Classes.FirstOrDefault(c => c.Type == typeof(T)) != null);
+        var foundMapping = mappings.FirstOrDefault(x => x.Classes.FirstOrDefault(c => c.Type == typeof(T)) is not null);
 
-        if (foundMapping == null)
+        if (foundMapping is null)
             throw new InvalidOperationException("Could not find mapping for class '" + typeof(T).Name + "'");
 
         document = new MappingXmlSerializer()
@@ -182,7 +182,7 @@ public MappingTester<T> ValueEquals(string value)
     public virtual MappingTester<T> ShouldBeInParentAtPosition(int elementPosition)
     {
         XmlElement parentElement = (XmlElement)currentElement.ParentNode;
-        if (parentElement == null)
+        if (parentElement is null)
         {
             Assert.Fail("Current element has no parent element.");
         }
diff --git a/src/FluentNHibernate.Testing/FluentInterfaceTests/SubclassMapWithUserTypeTests.cs b/src/FluentNHibernate.Testing/FluentInterfaceTests/SubclassMapWithUserTypeTests.cs
index 369673cec..dd09e38a0 100644
--- a/src/FluentNHibernate.Testing/FluentInterfaceTests/SubclassMapWithUserTypeTests.cs
+++ b/src/FluentNHibernate.Testing/FluentInterfaceTests/SubclassMapWithUserTypeTests.cs
@@ -113,7 +113,7 @@ public void NullSafeSet(DbCommand cmd, object value, int index, ISessionImplemen
     {
         IList<string> contexts = value as IList<string>;
 
-        if (contexts != null)
+        if (contexts is not null)
         {
             NHibernateUtil.Boolean.NullSafeSet(cmd, contexts.Contains("Icon"), index, session);
             NHibernateUtil.Boolean.NullSafeSet(cmd, contexts.Contains("Promo"), index + 1, session);
diff --git a/src/FluentNHibernate.Testing/PersistenceModelTests/SubclassPersistenceModelTests.cs b/src/FluentNHibernate.Testing/PersistenceModelTests/SubclassPersistenceModelTests.cs
index aaee7be96..860d53925 100644
--- a/src/FluentNHibernate.Testing/PersistenceModelTests/SubclassPersistenceModelTests.cs
+++ b/src/FluentNHibernate.Testing/PersistenceModelTests/SubclassPersistenceModelTests.cs
@@ -122,7 +122,7 @@ public void ShouldPickUpSubclassMapsWhenAddingFromAssembly()
             model.AddMappingsFromSource(new StubTypeSource(typeof(TablePerSubclass.TPS_ParentMap), typeof(TablePerSubclass.TPS_ChildMap)));
 
             var classMapping = model.BuildMappings()
-                .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(TablePerSubclass.TPS_Parent)) != null)
+                .First(x => x.Classes.FirstOrDefault(c => c.Type == typeof(TablePerSubclass.TPS_Parent)) is not null)
                 .Classes.First();
 
             classMapping.Subclasses.Count().ShouldBeGreaterThan(0);
diff --git a/src/FluentNHibernate.Testing/Testing/PersistenceSpecificationTransactionTest.cs b/src/FluentNHibernate.Testing/Testing/PersistenceSpecificationTransactionTest.cs
index cdcc07c64..086ec1eed 100644
--- a/src/FluentNHibernate.Testing/Testing/PersistenceSpecificationTransactionTest.cs
+++ b/src/FluentNHibernate.Testing/Testing/PersistenceSpecificationTransactionTest.cs
@@ -87,10 +87,10 @@ public class NameEqualityComparer : IEqualityComparer
     {
         bool IEqualityComparer.Equals(object x, object y)
         {
-            if (x == null || y == null)
+            if (x is null || y is null)
                 return false;
 
-            if (x.GetType().GetProperty("Name") != null && y.GetType().GetProperty("Name") != null)
+            if (x.GetType().GetProperty("Name") is not null && y.GetType().GetProperty("Name") is not null)
             {
                 return x.GetType().GetProperty("Name").GetValue(x, null) == y.GetType().GetProperty("Name").GetValue(x, null);
             }
diff --git a/src/FluentNHibernate.Testing/Testing/XmlWriterTestHelper.cs b/src/FluentNHibernate.Testing/Testing/XmlWriterTestHelper.cs
index e7504d5b6..829117e49 100644
--- a/src/FluentNHibernate.Testing/Testing/XmlWriterTestHelper.cs
+++ b/src/FluentNHibernate.Testing/Testing/XmlWriterTestHelper.cs
@@ -40,7 +40,7 @@ public void VerifyAll(IXmlWriter<TMappingType> writer)
         {
             TMappingType mapping;
 
-            if (constructor == null)
+            if (constructor is null)
                 mapping = (TMappingType)typeof(TMappingType).InstantiateUsingParameterlessConstructor();
             else
                 mapping = constructor();
diff --git a/src/FluentNHibernate/AssemblyTypeSource.cs b/src/FluentNHibernate/AssemblyTypeSource.cs
index d395fc3e0..409f52736 100644
--- a/src/FluentNHibernate/AssemblyTypeSource.cs
+++ b/src/FluentNHibernate/AssemblyTypeSource.cs
@@ -15,7 +15,7 @@ public class AssemblyTypeSource : ITypeSource
 
     public AssemblyTypeSource(Assembly source)
     {
-        if (source == null) throw new ArgumentNullException("source");
+        if (source is null) throw new ArgumentNullException("source");
 
         this.source = source;
     }
@@ -29,7 +29,7 @@ public IEnumerable<Type> GetTypes()
 
     public void LogSource(IDiagnosticLogger logger)
     {
-        if (logger == null) throw new ArgumentNullException("logger");
+        if (logger is null) throw new ArgumentNullException("logger");
 
         logger.LoadedFluentMappingsFromSource(this);
     }
diff --git a/src/FluentNHibernate/Automapping/Alterations/AutoMappingOverrideAlteration.cs b/src/FluentNHibernate/Automapping/Alterations/AutoMappingOverrideAlteration.cs
index a3d7ffc40..b0a330fcf 100644
--- a/src/FluentNHibernate/Automapping/Alterations/AutoMappingOverrideAlteration.cs
+++ b/src/FluentNHibernate/Automapping/Alterations/AutoMappingOverrideAlteration.cs
@@ -35,7 +35,7 @@ public void Alter(AutoPersistenceModel model)
             let entity = (from interfaceType in type.GetInterfaces()
                 where interfaceType.IsGenericType && interfaceType.GetGenericTypeDefinition() == typeof(IAutoMappingOverride<>)
                 select interfaceType.GetGenericArguments()[0]).FirstOrDefault()
-            where entity != null
+            where entity is not null
             select type;
 
         foreach (var type in types)
diff --git a/src/FluentNHibernate/Automapping/AutoMapper.cs b/src/FluentNHibernate/Automapping/AutoMapper.cs
index 186edaea1..4623a252f 100644
--- a/src/FluentNHibernate/Automapping/AutoMapper.cs
+++ b/src/FluentNHibernate/Automapping/AutoMapper.cs
@@ -43,7 +43,7 @@ public ClassMappingBase MergeMap(Type classType, ClassMappingBase mapping, IList
 
         ProcessClass(mapping, classType, mappedMembers);
 
-        if (mappingTypes != null)
+        if (mappingTypes is not null)
             MapInheritanceTree(classType, mapping, mappedMembers);
 
         return mapping;
@@ -56,11 +56,11 @@ private void MapInheritanceTree(Type classType, ClassMappingBase mapping, IList<
         var mappingTypesWithLogicalParents = GetMappingTypesWithLogicalParents();
 
         foreach (var inheritedClass in mappingTypesWithLogicalParents
-                     .Where(x => x.Value != null && x.Value.Type == classType)
+                     .Where(x => x.Value is not null && x.Value.Type == classType)
                      .Select(x => x.Key))
         {
             var tempMapping = mapping as ClassMapping;
-            var tempIsNull = tempMapping == null;
+            var tempIsNull = tempMapping is null;
             if (isDiscriminated && !discriminatorSet && !tempIsNull)
             {
                 var discriminatorColumn = cfg.GetDiscriminatorColumn(classType);
@@ -79,12 +79,12 @@ private void MapInheritanceTree(Type classType, ClassMappingBase mapping, IList<
 
             SubclassMapping subclassMapping;
             var tempSubClassMap = mapping as SubclassMapping;
-            if(!tempIsNull && tempMapping.IsUnionSubclass || tempSubClassMap != null && tempSubClassMap.SubclassType == SubclassType.UnionSubclass)
+            if(!tempIsNull && tempMapping.IsUnionSubclass || tempSubClassMap is not null && tempSubClassMap.SubclassType == SubclassType.UnionSubclass)
             {
                 subclassMapping = new SubclassMapping(SubclassType.UnionSubclass);
                 subclassMapping.Set(x => x.Type, Layer.Defaults, inheritedClass.Type);
             }
-            else if (isDiscriminated || tempSubClassMap != null && tempSubClassMap.SubclassType == SubclassType.Subclass)
+            else if (isDiscriminated || tempSubClassMap is not null && tempSubClassMap.SubclassType == SubclassType.Subclass)
             {
                 subclassMapping = new SubclassMapping(SubclassType.Subclass);
                 subclassMapping.Set(x => x.Type, Layer.Defaults, inheritedClass.Type);
@@ -111,7 +111,7 @@ private void MapInheritanceTree(Type classType, ClassMappingBase mapping, IList<
 
     static bool HasDiscriminator(ClassMappingBase mapping)
     {
-        if (mapping is ClassMapping && ((ClassMapping) mapping).Discriminator != null)
+        if (mapping is ClassMapping && ((ClassMapping) mapping).Discriminator is not null)
             return true;
 
         return false;
@@ -132,7 +132,7 @@ Dictionary<AutoMapType, AutoMapType> GetMappingTypesWithLogicalParents()
 
     static AutoMapType GetLogicalParent(Type type, IDictionary<Type, AutoMapType> availableTypes)
     {
-        if (type.BaseType == typeof(object) || type.BaseType == null)
+        if (type.BaseType == typeof(object) || type.BaseType is null)
             return null;
 
         AutoMapType baseType;
diff --git a/src/FluentNHibernate/Automapping/AutoMapping.cs b/src/FluentNHibernate/Automapping/AutoMapping.cs
index 06768d3ff..2a2d6193b 100644
--- a/src/FluentNHibernate/Automapping/AutoMapping.cs
+++ b/src/FluentNHibernate/Automapping/AutoMapping.cs
@@ -41,19 +41,19 @@ void IAutoClasslike.AlterModel(ClassMappingBase mapping)
         mapping.MergeAttributes(attributes.Clone());
         if (mapping is ClassMapping classMapping)
         {
-            if (providers.Id != null)
+            if (providers.Id is not null)
                 classMapping.Set(x => x.Id, Layer.Defaults, providers.Id.GetIdentityMapping());
 
-            if (providers.NaturalId != null)
+            if (providers.NaturalId is not null)
                 classMapping.Set(x => x.NaturalId, Layer.Defaults, providers.NaturalId.GetNaturalIdMapping());
 
-            if (providers.CompositeId != null)
+            if (providers.CompositeId is not null)
                 classMapping.Set(x => x.Id, Layer.Defaults, providers.CompositeId.GetCompositeIdMapping());
 
-            if (providers.Version != null)
+            if (providers.Version is not null)
                 classMapping.Set(x => x.Version, Layer.Defaults, providers.Version.GetVersionMapping());
 
-            if (providers.Discriminator != null)
+            if (providers.Discriminator is not null)
                 classMapping.Set(x => x.Discriminator, Layer.Defaults, providers.Discriminator.GetDiscriminatorMapping());
 
             if (Cache.IsDirty)
@@ -133,7 +133,7 @@ public AutoJoinedSubClassPart<TSubclass> JoinedSubClass<TSubclass>(string keyCol
         var genericType = typeof(AutoJoinedSubClassPart<>).MakeGenericType(typeof(TSubclass));
         var joinedclass = (AutoJoinedSubClassPart<TSubclass>)Activator.CreateInstance(genericType, keyColumn);
 
-        if (action != null)
+        if (action is not null)
             action(joinedclass);
 
         providers.Subclasses[typeof(TSubclass)] = joinedclass;
@@ -167,7 +167,7 @@ public AutoSubClassPart<TSubclass> SubClass<TSubclass>(object discriminatorValue
         var genericType = typeof(AutoSubClassPart<>).MakeGenericType(typeof(TSubclass));
         var subclass = (AutoSubClassPart<TSubclass>)Activator.CreateInstance(genericType, null, discriminatorValue);
 
-        if (action != null)
+        if (action is not null)
             action(subclass);
 
         // remove any mappings for the same type, then re-add
diff --git a/src/FluentNHibernate/Automapping/AutoMappingExpressions.cs b/src/FluentNHibernate/Automapping/AutoMappingExpressions.cs
index 85a668f55..236640169 100644
--- a/src/FluentNHibernate/Automapping/AutoMappingExpressions.cs
+++ b/src/FluentNHibernate/Automapping/AutoMappingExpressions.cs
@@ -69,7 +69,7 @@ public ExpressionBasedAutomappingConfiguration(AutoMappingExpressions expression
 
     public override bool ShouldMap(Member member)
     {
-        if (expressions.FindMembers != null)
+        if (expressions.FindMembers is not null)
             return expressions.FindMembers(member);
 
         return base.ShouldMap(member);
@@ -77,7 +77,7 @@ public override bool ShouldMap(Member member)
 
     public override bool IsId(Member member)
     {
-        if (expressions.FindIdentity != null)
+        if (expressions.FindIdentity is not null)
             return expressions.FindIdentity(member);
 
         return base.IsId(member);
@@ -85,7 +85,7 @@ public override bool IsId(Member member)
 
     public override Type GetParentSideForManyToMany(Type left, Type right)
     {
-        if (expressions.GetParentSideForManyToMany != null)
+        if (expressions.GetParentSideForManyToMany is not null)
             return expressions.GetParentSideForManyToMany(left, right);
 
         return base.GetParentSideForManyToMany(left, right);
@@ -93,7 +93,7 @@ public override Type GetParentSideForManyToMany(Type left, Type right)
 
     public override bool IsConcreteBaseType(Type type)
     {
-        if (expressions.IsConcreteBaseType != null)
+        if (expressions.IsConcreteBaseType is not null)
             return expressions.IsConcreteBaseType(type);
 
         return base.IsConcreteBaseType(type);
@@ -101,7 +101,7 @@ public override bool IsConcreteBaseType(Type type)
 
     public override bool IsComponent(Type type)
     {
-        if (expressions.IsComponentType != null)
+        if (expressions.IsComponentType is not null)
             return expressions.IsComponentType(type);
 
         return base.IsComponent(type);
@@ -109,7 +109,7 @@ public override bool IsComponent(Type type)
 
     public override string GetComponentColumnPrefix(Member member)
     {
-        if (expressions.GetComponentColumnPrefix != null)
+        if (expressions.GetComponentColumnPrefix is not null)
             return expressions.GetComponentColumnPrefix(member);
 
         return base.GetComponentColumnPrefix(member);
@@ -117,7 +117,7 @@ public override string GetComponentColumnPrefix(Member member)
 
     public override bool IsDiscriminated(Type type)
     {
-        if (expressions.IsDiscriminated != null)
+        if (expressions.IsDiscriminated is not null)
             return expressions.IsDiscriminated(type);
 
         return base.IsDiscriminated(type);
@@ -125,7 +125,7 @@ public override bool IsDiscriminated(Type type)
 
     public override string GetDiscriminatorColumn(Type type)
     {
-        if (expressions.DiscriminatorColumn != null)
+        if (expressions.DiscriminatorColumn is not null)
             return expressions.DiscriminatorColumn(type);
 
         return base.GetDiscriminatorColumn(type);
@@ -133,7 +133,7 @@ public override string GetDiscriminatorColumn(Type type)
 
     public override bool AbstractClassIsLayerSupertype(Type type)
     {
-        if (expressions.AbstractClassIsLayerSupertype != null)
+        if (expressions.AbstractClassIsLayerSupertype is not null)
             return expressions.AbstractClassIsLayerSupertype(type);
 
         return base.AbstractClassIsLayerSupertype(type);
@@ -141,7 +141,7 @@ public override bool AbstractClassIsLayerSupertype(Type type)
 
     public override string SimpleTypeCollectionValueColumn(Member member)
     {
-        if (expressions.SimpleTypeCollectionValueColumn != null)
+        if (expressions.SimpleTypeCollectionValueColumn is not null)
             return expressions.SimpleTypeCollectionValueColumn(member);
 
         return base.SimpleTypeCollectionValueColumn(member);
diff --git a/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs b/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
index ce93357d6..b3790320c 100644
--- a/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
+++ b/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
@@ -158,7 +158,7 @@ private void CompileMappings()
                 continue;
             }
             // skipped by inline where clause
-            if (whereClause != null && !whereClause(type))
+            if (whereClause is not null && !whereClause(type))
             {
                 log.AutomappingSkippedType(type, "Skipped by Where clause");
                 continue;
@@ -187,7 +187,7 @@ private int InheritanceHierarchyDepth(Type type)
         var depth = 0;
         var parent = type;
 
-        while (parent != null && parent != typeof(object))
+        while (parent is not null && parent != typeof(object))
         {
             parent = parent.BaseType;
             depth++;
@@ -295,7 +295,7 @@ public IMappingProvider FindMapping(Type type)
 
         var mapping = classProviders.FirstOrDefault(t => finder(t, type));
 
-        if (mapping != null) return mapping;
+        if (mapping is not null) return mapping;
 
         // if we haven't found a map yet then try to find a map of the
         // base type to merge if not a concrete base type
@@ -383,7 +383,7 @@ public void Override(Type overrideType)
                 MethodInfo overrideHelperMethod = typeof(AutoPersistenceModel)
                     .GetMethod("OverrideHelper", BindingFlags.NonPublic | BindingFlags.Instance);
 
-                if (overrideHelperMethod == null) return;
+                if (overrideHelperMethod is null) return;
 
                 overrideHelperMethod
                     .MakeGenericMethod(entityType)
diff --git a/src/FluentNHibernate/Automapping/AutoSubClassPart.cs b/src/FluentNHibernate/Automapping/AutoSubClassPart.cs
index 39c3bc41c..69e208b8a 100644
--- a/src/FluentNHibernate/Automapping/AutoSubClassPart.cs
+++ b/src/FluentNHibernate/Automapping/AutoSubClassPart.cs
@@ -70,7 +70,7 @@ public void SubClass<TSubclass>(string discriminatorValue, Action<AutoSubClassPa
         var genericType = typeof(AutoSubClassPart<>).MakeGenericType(typeof(TSubclass));
         var subclass = (AutoSubClassPart<TSubclass>)Activator.CreateInstance(genericType, discriminatorValue);
 
-        if (action != null) action(subclass);
+        if (action is not null) action(subclass);
 
         providers.Subclasses[typeof(TSubclass)] = subclass;
     }
diff --git a/src/FluentNHibernate/Automapping/Steps/HasManyToManyStep.cs b/src/FluentNHibernate/Automapping/Steps/HasManyToManyStep.cs
index 8715828f4..b47c364c4 100644
--- a/src/FluentNHibernate/Automapping/Steps/HasManyToManyStep.cs
+++ b/src/FluentNHibernate/Automapping/Steps/HasManyToManyStep.cs
@@ -28,7 +28,7 @@ public bool ShouldMap(Member member)
         if (type.HasInterface(typeof(IDictionary)) || type.ClosesInterface(typeof(IDictionary<,>)) || type.Closes(typeof(System.Collections.Generic.IDictionary<,>)))
             return false;
 
-        var hasInverse = GetInverseProperty(member) != null;
+        var hasInverse = GetInverseProperty(member) is not null;
         return hasInverse;
     }
 
diff --git a/src/FluentNHibernate/Automapping/Steps/PropertyStep.cs b/src/FluentNHibernate/Automapping/Steps/PropertyStep.cs
index 144d0941f..c57925f61 100644
--- a/src/FluentNHibernate/Automapping/Steps/PropertyStep.cs
+++ b/src/FluentNHibernate/Automapping/Steps/PropertyStep.cs
@@ -48,7 +48,7 @@ private bool HasExplicitTypeConvention(Member property)
                 var criteria = new ConcreteAcceptanceCriteria<IPropertyInspector>();
                 var acceptance = c as IConventionAcceptance<IPropertyInspector>;
                     
-                if (acceptance != null)
+                if (acceptance is not null)
                     acceptance.Accept(criteria);
 
                 var propertyMapping = new PropertyMapping
@@ -59,7 +59,7 @@ private bool HasExplicitTypeConvention(Member property)
                 return criteria.Matches(new PropertyInspector(propertyMapping));
             });
 
-        return conventions.FirstOrDefault() != null;
+        return conventions.FirstOrDefault() is not null;
     }
 
     private static bool IsMappableToColumnType(Member property)
diff --git a/src/FluentNHibernate/Cfg/AutoMappingsContainer.cs b/src/FluentNHibernate/Cfg/AutoMappingsContainer.cs
index aae608fd4..5d5f7c40d 100644
--- a/src/FluentNHibernate/Cfg/AutoMappingsContainer.cs
+++ b/src/FluentNHibernate/Cfg/AutoMappingsContainer.cs
@@ -79,7 +79,7 @@ internal void Apply(Configuration cfg, PersistenceModel model)
             if (!string.IsNullOrEmpty(exportPath))
                 mapping.WriteMappingsTo(exportPath);
 
-            if (exportTextWriter != null)
+            if (exportTextWriter is not null)
                 mapping.WriteMappingsTo(exportTextWriter);
 
             mapping.ImportProviders(model);
diff --git a/src/FluentNHibernate/Cfg/FluentConfiguration.cs b/src/FluentNHibernate/Cfg/FluentConfiguration.cs
index b195f204c..1c5a90fc9 100644
--- a/src/FluentNHibernate/Cfg/FluentConfiguration.cs
+++ b/src/FluentNHibernate/Cfg/FluentConfiguration.cs
@@ -213,7 +213,7 @@ public FluentConfiguration Mappings(Action<MappingConfiguration> mappings)
     /// <returns>Fluent configuration</returns>
     public FluentConfiguration ExposeConfiguration(Action<Configuration> config)
     {
-        if (config != null)
+        if (config is not null)
             configAlterations.Add(config);
 
         return this;
diff --git a/src/FluentNHibernate/Cfg/FluentMappingsContainer.cs b/src/FluentNHibernate/Cfg/FluentMappingsContainer.cs
index f2014ad08..3e34c925b 100644
--- a/src/FluentNHibernate/Cfg/FluentMappingsContainer.cs
+++ b/src/FluentNHibernate/Cfg/FluentMappingsContainer.cs
@@ -69,7 +69,7 @@ public FluentMappingsContainer Add<T>()
     /// <returns>Fluent mappings configuration</returns>
     public FluentMappingsContainer Add(Type type)
     {
-        if (type == null)
+        if (type is null)
             throw new ArgumentNullException("type");
 
         types.Add(type);
@@ -132,10 +132,10 @@ internal void Apply(PersistenceModel model)
         if (!string.IsNullOrEmpty(exportPath))
             model.WriteMappingsTo(exportPath);
 
-        if (exportTextWriter != null)
+        if (exportTextWriter is not null)
             model.WriteMappingsTo(exportTextWriter);
 
-        if (biDirectionalManyToManyPairer != null)
+        if (biDirectionalManyToManyPairer is not null)
             model.BiDirectionalManyToManyPairer = biDirectionalManyToManyPairer;
     }
 }
diff --git a/src/FluentNHibernate/Conventions/AcceptanceCriteria/EmptyCriterion.cs b/src/FluentNHibernate/Conventions/AcceptanceCriteria/EmptyCriterion.cs
index eb9771e94..0d1fcbf72 100644
--- a/src/FluentNHibernate/Conventions/AcceptanceCriteria/EmptyCriterion.cs
+++ b/src/FluentNHibernate/Conventions/AcceptanceCriteria/EmptyCriterion.cs
@@ -22,7 +22,7 @@ public bool IsSatisfiedBy<T>(Expression<Func<T, object>> propertyExpression, T i
         if (!(actualValue is IEnumerable))
             return false;
 
-        var result = ((IEnumerable)actualValue).GetEnumerator().Current != null;
+        var result = ((IEnumerable)actualValue).GetEnumerator().Current is not null;
 
         return inverse ? !result : result;
     }
diff --git a/src/FluentNHibernate/Conventions/AttributeCollectionConvention.cs b/src/FluentNHibernate/Conventions/AttributeCollectionConvention.cs
index d054431f3..e6116d4ad 100644
--- a/src/FluentNHibernate/Conventions/AttributeCollectionConvention.cs
+++ b/src/FluentNHibernate/Conventions/AttributeCollectionConvention.cs
@@ -15,7 +15,7 @@ public abstract class AttributeCollectionConvention<T> : ICollectionConvention,
 {
     public void Accept(IAcceptanceCriteria<ICollectionInspector> criteria)
     {
-        criteria.Expect(property => Attribute.GetCustomAttribute(property.Member, typeof(T)) as T != null);
+        criteria.Expect(property => Attribute.GetCustomAttribute(property.Member, typeof(T)) as T is not null);
     }
 
     public void Apply(ICollectionInstance instance)
diff --git a/src/FluentNHibernate/Conventions/AttributePropertyConvention.cs b/src/FluentNHibernate/Conventions/AttributePropertyConvention.cs
index ffe1636f7..f87bc7040 100644
--- a/src/FluentNHibernate/Conventions/AttributePropertyConvention.cs
+++ b/src/FluentNHibernate/Conventions/AttributePropertyConvention.cs
@@ -15,7 +15,7 @@ public abstract class AttributePropertyConvention<T> : IPropertyConvention, IPro
 {
     public void Accept(IAcceptanceCriteria<IPropertyInspector> criteria)
     {
-        criteria.Expect(property => Attribute.GetCustomAttribute(property.Property.MemberInfo, typeof(T)) as T != null);
+        criteria.Expect(property => Attribute.GetCustomAttribute(property.Property.MemberInfo, typeof(T)) as T is not null);
     }
 
     public void Apply(IPropertyInstance instance)
diff --git a/src/FluentNHibernate/Conventions/DefaultConventionFinder.cs b/src/FluentNHibernate/Conventions/DefaultConventionFinder.cs
index 10c193e71..6ee0892e8 100644
--- a/src/FluentNHibernate/Conventions/DefaultConventionFinder.cs
+++ b/src/FluentNHibernate/Conventions/DefaultConventionFinder.cs
@@ -141,7 +141,7 @@ private void Add(Type type, MissingConstructor missingConstructor)
 
     private bool AllowMultiplesOf(Type type)
     {
-        return Attribute.GetCustomAttribute(type, typeof(MultipleAttribute), true) != null;
+        return Attribute.GetCustomAttribute(type, typeof(MultipleAttribute), true) is not null;
     }
 
     private object Instantiate(Type type)
diff --git a/src/FluentNHibernate/Conventions/EnumerableExtensionsForConventions.cs b/src/FluentNHibernate/Conventions/EnumerableExtensionsForConventions.cs
index 91aa22432..fd5ecf196 100644
--- a/src/FluentNHibernate/Conventions/EnumerableExtensionsForConventions.cs
+++ b/src/FluentNHibernate/Conventions/EnumerableExtensionsForConventions.cs
@@ -32,7 +32,7 @@ public static bool Contains<T>(this IEnumerable<T> collection, Func<T, bool> pre
     {
         var item = collection.FirstOrDefault(prediate);
 
-        return item != null;
+        return item is not null;
     }
 
     public static bool IsEmpty<T>(this IEnumerable<T> collection)
diff --git a/src/FluentNHibernate/Conventions/Helpers/Prebuilt/BuiltSuffixForeignKeyConvention.cs b/src/FluentNHibernate/Conventions/Helpers/Prebuilt/BuiltSuffixForeignKeyConvention.cs
index 34b26818d..2cda0880a 100644
--- a/src/FluentNHibernate/Conventions/Helpers/Prebuilt/BuiltSuffixForeignKeyConvention.cs
+++ b/src/FluentNHibernate/Conventions/Helpers/Prebuilt/BuiltSuffixForeignKeyConvention.cs
@@ -13,6 +13,6 @@ public BuiltSuffixForeignKeyConvention(string suffix)
 
     protected override string GetKeyName(Member property, Type type)
     {
-        return (property != null ? property.Name : type.Name) + suffix;
+        return (property is not null ? property.Name : type.Name) + suffix;
     }
 }
diff --git a/src/FluentNHibernate/Conventions/Inspections/Cascade.cs b/src/FluentNHibernate/Conventions/Inspections/Cascade.cs
index 2245e117e..0fdb9b9cd 100644
--- a/src/FluentNHibernate/Conventions/Inspections/Cascade.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/Cascade.cs
@@ -32,7 +32,7 @@ public bool Equals(Cascade other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Cascade x, Cascade y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/ClassInspector.cs b/src/FluentNHibernate/Conventions/Inspections/ClassInspector.cs
index c9d9bc5b6..3ef0d7b89 100644
--- a/src/FluentNHibernate/Conventions/Inspections/ClassInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/ClassInspector.cs
@@ -56,7 +56,7 @@ public ICacheInstance Cache
     {
         get
         {
-            if (mapping.Cache == null)
+            if (mapping.Cache is null)
                 // conventions are hitting it, user must want a cache
                 mapping.Set(x => x.Cache, Layer.Conventions, new CacheMapping());
 
@@ -103,7 +103,7 @@ public IVersionInspector Version
     {
         get
         {
-            if (mapping.Version == null)
+            if (mapping.Version is null)
                 return new VersionInspector(new VersionMapping());
 
             return new VersionInspector(mapping.Version);
@@ -203,7 +203,7 @@ public IDiscriminatorInspector Discriminator
     {
         get
         {
-            if (mapping.Discriminator == null)
+            if (mapping.Discriminator is null)
                 // deliberately empty so nothing evaluates to true
                 return new DiscriminatorInspector(new DiscriminatorMapping());
 
@@ -255,7 +255,7 @@ public IIdentityInspectorBase Id
     {
         get
         {
-            if (mapping.Id == null)
+            if (mapping.Id is null)
                 return new IdentityInspector(new IdMapping());
             if (mapping.Id is CompositeIdMapping)
                 return new CompositeIdentityInspector((CompositeIdMapping)mapping.Id);
diff --git a/src/FluentNHibernate/Conventions/Inspections/CollectionInspector.cs b/src/FluentNHibernate/Conventions/Inspections/CollectionInspector.cs
index 967dcf8da..be962d097 100644
--- a/src/FluentNHibernate/Conventions/Inspections/CollectionInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/CollectionInspector.cs
@@ -50,7 +50,7 @@ public IKeyInspector Key
     {
         get
         {
-            if (mapping.Key == null)
+            if (mapping.Key is null)
                 return new KeyInspector(new KeyMapping());
 
             return new KeyInspector(mapping.Key);
@@ -122,7 +122,7 @@ public ICacheInspector Cache
     {
         get
         {
-            if (mapping.Cache == null)
+            if (mapping.Cache is null)
                 return new CacheInspector(new CacheMapping());
 
             return new CacheInspector(mapping.Cache);
@@ -148,7 +148,7 @@ public ICompositeElementInspector CompositeElement
     {
         get
         {
-            if (mapping.CompositeElement == null)
+            if (mapping.CompositeElement is null)
                 return new CompositeElementInspector(new CompositeElementMapping());
 
             return new CompositeElementInspector(mapping.CompositeElement);
@@ -159,7 +159,7 @@ public IElementInspector Element
     {
         get
         {
-            if (mapping.Element == null)
+            if (mapping.Element is null)
                 return new ElementInspector(new ElementMapping());
 
             return new ElementInspector(mapping.Element);
@@ -205,7 +205,7 @@ public IIndexInspectorBase Index
     {
         get
         {
-            if (mapping.Index == null)
+            if (mapping.Index is null)
                 return new IndexInspector(new IndexMapping());
 
             if (mapping.Index is IndexMapping)
diff --git a/src/FluentNHibernate/Conventions/Inspections/ColumnBasedInspector.cs b/src/FluentNHibernate/Conventions/Inspections/ColumnBasedInspector.cs
index 0b50074f1..6bdcd520c 100644
--- a/src/FluentNHibernate/Conventions/Inspections/ColumnBasedInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/ColumnBasedInspector.cs
@@ -23,7 +23,7 @@ private T GetValueFromColumns<T>(Func<ColumnMapping, object> property)
     {
         var column = columns.FirstOrDefault();
 
-        if (column != null)
+        if (column is not null)
             return (T)property(column);
 
         return default(T);
diff --git a/src/FluentNHibernate/Conventions/Inspections/ComponentBaseInspector.cs b/src/FluentNHibernate/Conventions/Inspections/ComponentBaseInspector.cs
index 1be45ada7..721dc2021 100644
--- a/src/FluentNHibernate/Conventions/Inspections/ComponentBaseInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/ComponentBaseInspector.cs
@@ -42,7 +42,7 @@ public IParentInspector Parent
     {
         get
         {
-            if (mapping.Parent == null)
+            if (mapping.Parent is null)
                 return new ParentInspector(new ParentMapping());
 
             return new ParentInspector(mapping.Parent);
diff --git a/src/FluentNHibernate/Conventions/Inspections/CompositeElementInspector.cs b/src/FluentNHibernate/Conventions/Inspections/CompositeElementInspector.cs
index 50331e6da..a1e4146ca 100644
--- a/src/FluentNHibernate/Conventions/Inspections/CompositeElementInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/CompositeElementInspector.cs
@@ -40,7 +40,7 @@ public IParentInspector Parent
     {
         get
         {
-            if (mapping.Parent == null)
+            if (mapping.Parent is null)
                 return new ParentInspector(new ParentMapping());
 
             return new ParentInspector(mapping.Parent);
diff --git a/src/FluentNHibernate/Conventions/Inspections/Fetch.cs b/src/FluentNHibernate/Conventions/Inspections/Fetch.cs
index ce5640dff..33397824f 100644
--- a/src/FluentNHibernate/Conventions/Inspections/Fetch.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/Fetch.cs
@@ -28,7 +28,7 @@ public bool Equals(Fetch other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Fetch x, Fetch y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/Generated.cs b/src/FluentNHibernate/Conventions/Inspections/Generated.cs
index 8126f3894..308312aa8 100644
--- a/src/FluentNHibernate/Conventions/Inspections/Generated.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/Generated.cs
@@ -45,7 +45,7 @@ public bool Equals(Generated other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Generated x, Generated y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/IdentityInspector.cs b/src/FluentNHibernate/Conventions/Inspections/IdentityInspector.cs
index b7c74be92..ac8277f71 100644
--- a/src/FluentNHibernate/Conventions/Inspections/IdentityInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/IdentityInspector.cs
@@ -53,7 +53,7 @@ public IGeneratorInspector Generator
     {
         get
         {
-            if (mapping.Generator == null)
+            if (mapping.Generator is null)
                 return new GeneratorInspector(new GeneratorMapping());
 
             return new GeneratorInspector(mapping.Generator);
diff --git a/src/FluentNHibernate/Conventions/Inspections/Include.cs b/src/FluentNHibernate/Conventions/Inspections/Include.cs
index d59099f9b..315507f11 100644
--- a/src/FluentNHibernate/Conventions/Inspections/Include.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/Include.cs
@@ -32,7 +32,7 @@ public bool Equals(Include other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Include x, Include y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/JoinInspector.cs b/src/FluentNHibernate/Conventions/Inspections/JoinInspector.cs
index 4357075dc..b86656afd 100644
--- a/src/FluentNHibernate/Conventions/Inspections/JoinInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/JoinInspector.cs
@@ -54,7 +54,7 @@ public IKeyInspector Key
     {
         get
         {
-            if (mapping.Key == null)
+            if (mapping.Key is null)
                 return new KeyInspector(new KeyMapping());
 
             return new KeyInspector(mapping.Key);
diff --git a/src/FluentNHibernate/Conventions/Inspections/JoinedSubclassInspector.cs b/src/FluentNHibernate/Conventions/Inspections/JoinedSubclassInspector.cs
index 99991d758..198d0cd8a 100644
--- a/src/FluentNHibernate/Conventions/Inspections/JoinedSubclassInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/JoinedSubclassInspector.cs
@@ -51,7 +51,7 @@ public IKeyInspector Key
     {
         get
         {
-            if (mapping.Key == null)
+            if (mapping.Key is null)
                 return new KeyInspector(new KeyMapping());
 
             return new KeyInspector(mapping.Key);
diff --git a/src/FluentNHibernate/Conventions/Inspections/NotFound.cs b/src/FluentNHibernate/Conventions/Inspections/NotFound.cs
index 60a37fdd6..e3d2bc7af 100644
--- a/src/FluentNHibernate/Conventions/Inspections/NotFound.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/NotFound.cs
@@ -27,7 +27,7 @@ public bool Equals(NotFound other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(NotFound x, NotFound y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/OnDelete.cs b/src/FluentNHibernate/Conventions/Inspections/OnDelete.cs
index ebed69de7..6bf96741f 100644
--- a/src/FluentNHibernate/Conventions/Inspections/OnDelete.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/OnDelete.cs
@@ -27,7 +27,7 @@ public bool Equals(OnDelete other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(OnDelete x, OnDelete y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/OptimisticLock.cs b/src/FluentNHibernate/Conventions/Inspections/OptimisticLock.cs
index 9c1cd4d89..0b840639e 100644
--- a/src/FluentNHibernate/Conventions/Inspections/OptimisticLock.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/OptimisticLock.cs
@@ -29,7 +29,7 @@ public bool Equals(OptimisticLock other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(OptimisticLock x, OptimisticLock y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/ParentInspector.cs b/src/FluentNHibernate/Conventions/Inspections/ParentInspector.cs
index f5708b0bf..3f1d27cb8 100644
--- a/src/FluentNHibernate/Conventions/Inspections/ParentInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/ParentInspector.cs
@@ -38,7 +38,7 @@ public Access Access
     {
         get
         {
-            if (mapping.Access != null)
+            if (mapping.Access is not null)
                 return Access.FromString(mapping.Access);
              
             return null;
diff --git a/src/FluentNHibernate/Conventions/Inspections/Polymorphism.cs b/src/FluentNHibernate/Conventions/Inspections/Polymorphism.cs
index 2247a8741..c749e83c9 100644
--- a/src/FluentNHibernate/Conventions/Inspections/Polymorphism.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/Polymorphism.cs
@@ -27,7 +27,7 @@ public bool Equals(Polymorphism other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Polymorphism x, Polymorphism y)
diff --git a/src/FluentNHibernate/Conventions/Inspections/PropertyInspector.cs b/src/FluentNHibernate/Conventions/Inspections/PropertyInspector.cs
index ac39df01d..863210330 100644
--- a/src/FluentNHibernate/Conventions/Inspections/PropertyInspector.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/PropertyInspector.cs
@@ -75,7 +75,7 @@ public Access Access
     {
         get
         {
-            if (mapping.Access != null)
+            if (mapping.Access is not null)
                 return Access.FromString(mapping.Access);
 
             return Access.Unset;
diff --git a/src/FluentNHibernate/Conventions/Inspections/SchemaAction.cs b/src/FluentNHibernate/Conventions/Inspections/SchemaAction.cs
index 9af5f83eb..af69dfb85 100644
--- a/src/FluentNHibernate/Conventions/Inspections/SchemaAction.cs
+++ b/src/FluentNHibernate/Conventions/Inspections/SchemaAction.cs
@@ -31,7 +31,7 @@ public bool Equals(SchemaAction other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(SchemaAction x, SchemaAction y)
diff --git a/src/FluentNHibernate/Conventions/Instances/CollectionInstance.cs b/src/FluentNHibernate/Conventions/Instances/CollectionInstance.cs
index 2112ccb02..efdac8a5a 100644
--- a/src/FluentNHibernate/Conventions/Instances/CollectionInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/CollectionInstance.cs
@@ -93,7 +93,7 @@ public CollectionInstance(CollectionMapping mapping)
     {
         get
         {
-            if (mapping.Index == null)
+            if (mapping.Index is null)
                 return new IndexInstance(new IndexMapping());
 
             if (mapping.Index is IndexMapping)
@@ -184,7 +184,7 @@ void ICollectionInstance.AsBag()
     void ICollectionInstance.AsList()
     {
         mapping.Collection = Collection.List;
-        if (mapping.Index == null)
+        if (mapping.Index is null)
         {
             var indexMapping = new IndexMapping();
             var columnMapping = new ColumnMapping();
@@ -218,7 +218,7 @@ public ICollectionInstance Not
     {
         get
         {
-            if (mapping.Cache == null)
+            if (mapping.Cache is null)
                 // conventions are hitting it, user must want a cache
                 mapping.Set(x => x.Cache, Layer.Conventions, new CacheMapping());
 
@@ -245,7 +245,7 @@ public void SetOrderBy(string orderBy)
     {
         get
         {
-            if (mapping.Element == null)
+            if (mapping.Element is null)
                 mapping.Set(x => x.Element, Layer.Conventions, new ElementMapping());
                 
             return new ElementInstance(mapping.Element);
diff --git a/src/FluentNHibernate/Conventions/Instances/ElementInstance.cs b/src/FluentNHibernate/Conventions/Instances/ElementInstance.cs
index 3d94b1372..146cbfbf2 100644
--- a/src/FluentNHibernate/Conventions/Instances/ElementInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/ElementInstance.cs
@@ -19,7 +19,7 @@ public ElementInstance(ElementMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/IdentityInstance.cs b/src/FluentNHibernate/Conventions/Instances/IdentityInstance.cs
index 8df1dbda1..939b09e27 100644
--- a/src/FluentNHibernate/Conventions/Instances/IdentityInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/IdentityInstance.cs
@@ -21,7 +21,7 @@ public IdentityInstance(IdMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/IndexInstance.cs b/src/FluentNHibernate/Conventions/Instances/IndexInstance.cs
index bf34fd093..b61fab790 100644
--- a/src/FluentNHibernate/Conventions/Instances/IndexInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/IndexInstance.cs
@@ -22,7 +22,7 @@ public IndexInstance(IndexMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
         mapping.AddColumn(Layer.Conventions, column);
diff --git a/src/FluentNHibernate/Conventions/Instances/IndexManyToManyInstance.cs b/src/FluentNHibernate/Conventions/Instances/IndexManyToManyInstance.cs
index 3da271ed5..16f051518 100644
--- a/src/FluentNHibernate/Conventions/Instances/IndexManyToManyInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/IndexManyToManyInstance.cs
@@ -22,7 +22,7 @@ public IndexManyToManyInstance(IndexManyToManyMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
         mapping.AddColumn(Layer.Conventions, column);
diff --git a/src/FluentNHibernate/Conventions/Instances/JoinedSubclassInstance.cs b/src/FluentNHibernate/Conventions/Instances/JoinedSubclassInstance.cs
index 31593dc55..53d71205a 100644
--- a/src/FluentNHibernate/Conventions/Instances/JoinedSubclassInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/JoinedSubclassInstance.cs
@@ -22,7 +22,7 @@ public JoinedSubclassInstance(SubclassMapping mapping)
     {
         get
         {
-            if (mapping.Key == null)
+            if (mapping.Key is null)
                 mapping.Set(x => x.Key, Layer.Conventions, new KeyMapping());
 
             return new KeyInstance(mapping.Key);
diff --git a/src/FluentNHibernate/Conventions/Instances/KeyInstance.cs b/src/FluentNHibernate/Conventions/Instances/KeyInstance.cs
index 07a57a5ea..23a4dab67 100644
--- a/src/FluentNHibernate/Conventions/Instances/KeyInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/KeyInstance.cs
@@ -18,7 +18,7 @@ public KeyInstance(KeyMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/ManyToManyCollectionInstance.cs b/src/FluentNHibernate/Conventions/Instances/ManyToManyCollectionInstance.cs
index e9941a3df..9d26b182f 100644
--- a/src/FluentNHibernate/Conventions/Instances/ManyToManyCollectionInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/ManyToManyCollectionInstance.cs
@@ -36,7 +36,7 @@ public IManyToManyCollectionInstance OtherSide
         get
         {
             var otherSide = mapping.OtherSide as CollectionMapping;
-            if (otherSide == null)
+            if (otherSide is null)
                 return null;
 
             return new ManyToManyCollectionInstance(otherSide);
diff --git a/src/FluentNHibernate/Conventions/Instances/ManyToManyInstance.cs b/src/FluentNHibernate/Conventions/Instances/ManyToManyInstance.cs
index 56943cc14..5ac093b40 100644
--- a/src/FluentNHibernate/Conventions/Instances/ManyToManyInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/ManyToManyInstance.cs
@@ -20,7 +20,7 @@ public ManyToManyInstance(ManyToManyMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/ManyToOneInstance.cs b/src/FluentNHibernate/Conventions/Instances/ManyToOneInstance.cs
index 6ef98a45b..2268f9dec 100644
--- a/src/FluentNHibernate/Conventions/Instances/ManyToOneInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/ManyToOneInstance.cs
@@ -21,7 +21,7 @@ public ManyToOneInstance(ManyToOneMapping mapping)
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, Layer.Conventions, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/OneToManyCollectionInstance.cs b/src/FluentNHibernate/Conventions/Instances/OneToManyCollectionInstance.cs
index 0843742c0..8259a94bf 100644
--- a/src/FluentNHibernate/Conventions/Instances/OneToManyCollectionInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/OneToManyCollectionInstance.cs
@@ -31,7 +31,7 @@ public IManyToOneInstance OtherSide
         get
         {
             var otherSide = mapping.OtherSide as ManyToOneMapping;
-            if (otherSide == null)
+            if (otherSide is null)
                 return null;
 
             return new ManyToOneInstance(otherSide);
diff --git a/src/FluentNHibernate/Conventions/Instances/PropertyInstance.cs b/src/FluentNHibernate/Conventions/Instances/PropertyInstance.cs
index 96e3beb47..d6d9f387c 100644
--- a/src/FluentNHibernate/Conventions/Instances/PropertyInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/PropertyInstance.cs
@@ -149,7 +149,7 @@ public IPropertyInstance Not
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, layer, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/Instances/VersionInstance.cs b/src/FluentNHibernate/Conventions/Instances/VersionInstance.cs
index 35f3bb58e..37a1be1da 100644
--- a/src/FluentNHibernate/Conventions/Instances/VersionInstance.cs
+++ b/src/FluentNHibernate/Conventions/Instances/VersionInstance.cs
@@ -42,7 +42,7 @@ public IVersionInstance Not
     public void Column(string columnName)
     {
         var originalColumn = mapping.Columns.FirstOrDefault();
-        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone();
+        var column = originalColumn is null ? new ColumnMapping() : originalColumn.Clone();
 
         column.Set(x => x.Name, layer, columnName);
 
diff --git a/src/FluentNHibernate/Conventions/ManyToManyTableNameConvention.cs b/src/FluentNHibernate/Conventions/ManyToManyTableNameConvention.cs
index d440a2583..99fb9b297 100644
--- a/src/FluentNHibernate/Conventions/ManyToManyTableNameConvention.cs
+++ b/src/FluentNHibernate/Conventions/ManyToManyTableNameConvention.cs
@@ -12,7 +12,7 @@ public abstract class ManyToManyTableNameConvention : IHasManyToManyConvention
 {
     public void Apply(IManyToManyCollectionInstance instance)
     {
-        if (instance.OtherSide == null)
+        if (instance.OtherSide is null)
         {
             // uni-directional
             var tableName = GetUniDirectionalTableName(instance);
diff --git a/src/FluentNHibernate/Conventions/ProxyConvention.cs b/src/FluentNHibernate/Conventions/ProxyConvention.cs
index f64c7f91d..e188c2a18 100644
--- a/src/FluentNHibernate/Conventions/ProxyConvention.cs
+++ b/src/FluentNHibernate/Conventions/ProxyConvention.cs
@@ -13,12 +13,12 @@ public ProxyConvention(
         Func<Type, Type> mapPersistentTypeToProxyInterfaceType,
         Func<Type, Type> mapProxyInterfaceTypeToPersistentType)
     {
-        if (mapPersistentTypeToProxyInterfaceType == null)
+        if (mapPersistentTypeToProxyInterfaceType is null)
         {
             throw new ArgumentNullException("mapPersistentTypeToProxyInterfaceType");
         }
 
-        if(mapProxyInterfaceTypeToPersistentType == null)
+        if(mapProxyInterfaceTypeToPersistentType is null)
         {
             throw new ArgumentNullException("mapProxyInterfaceTypeToPersistentType");
         }
@@ -35,7 +35,7 @@ public void Apply(IClassInstance instance)
     {
         var proxy = GetProxyType(instance.EntityType);
 
-        if(proxy != null)
+        if(proxy is not null)
         {
             instance.Proxy(proxy);
         }
@@ -48,7 +48,7 @@ public void Apply(ISubclassInstance instance)
     {
         var proxy = GetProxyType(instance.EntityType);
 
-        if(proxy != null)
+        if(proxy is not null)
         {
             instance.Proxy(proxy);
         }
@@ -62,7 +62,7 @@ public void Apply(IManyToOneInstance instance)
         Type inferredType = instance.Class.GetUnderlyingSystemType();
         Type persistentType = _mapProxyInterfaceTypeToPersistentType(inferredType);
 
-        if (persistentType != null)
+        if (persistentType is not null)
         {
             instance.OverrideInferredClass(persistentType);
         }
@@ -75,7 +75,7 @@ public void Apply(ICollectionInstance instance)
     {
         var proxy = GetPersistentType(instance.Relationship.Class.GetUnderlyingSystemType());
 
-        if(proxy != null)
+        if(proxy is not null)
         {
             instance.Relationship.CustomClass(proxy);
         }
@@ -89,7 +89,7 @@ public void Apply(IOneToOneInstance instance)
         Type inferredType = ((IOneToOneInspector)instance).Class.GetUnderlyingSystemType();
         Type persistentType = _mapProxyInterfaceTypeToPersistentType(inferredType);
 
-        if(persistentType != null)
+        if(persistentType is not null)
         {
             instance.OverrideInferredClass(persistentType);
         }
diff --git a/src/FluentNHibernate/Diagnostics/SkippedAutomappingType.cs b/src/FluentNHibernate/Diagnostics/SkippedAutomappingType.cs
index 693005ce9..864e790f1 100644
--- a/src/FluentNHibernate/Diagnostics/SkippedAutomappingType.cs
+++ b/src/FluentNHibernate/Diagnostics/SkippedAutomappingType.cs
@@ -26,7 +26,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((Type != null ? Type.GetHashCode() : 0) * 397) ^ (Reason != null ? Reason.GetHashCode() : 0);
+            return ((Type is not null ? Type.GetHashCode() : 0) * 397) ^ (Reason is not null ? Reason.GetHashCode() : 0);
         }
     }
 }
diff --git a/src/FluentNHibernate/DummyPropertyInfo.cs b/src/FluentNHibernate/DummyPropertyInfo.cs
index a802b298d..46871c63a 100644
--- a/src/FluentNHibernate/DummyPropertyInfo.cs
+++ b/src/FluentNHibernate/DummyPropertyInfo.cs
@@ -12,8 +12,8 @@ public sealed class DummyPropertyInfo : PropertyInfo
 
     public DummyPropertyInfo(string name, Type type)
     {
-        if (name == null) throw new ArgumentNullException("name");
-        if (type == null) throw new ArgumentNullException("type");
+        if (name is null) throw new ArgumentNullException("name");
+        if (type is null) throw new ArgumentNullException("type");
 
         this.name = name;
         this.type = type;
diff --git a/src/FluentNHibernate/Infrastructure/NetStandardSerialization.cs b/src/FluentNHibernate/Infrastructure/NetStandardSerialization.cs
index 7d45ca85c..49eb9e672 100644
--- a/src/FluentNHibernate/Infrastructure/NetStandardSerialization.cs
+++ b/src/FluentNHibernate/Infrastructure/NetStandardSerialization.cs
@@ -41,7 +41,7 @@ internal sealed class TypeReference : IObjectReference
 
             public TypeReference(Type type)
             {
-                if (type == null)
+                if (type is null)
                     throw new ArgumentNullException(nameof(type));
 
                 AssemblyName = type.Assembly.FullName;
@@ -83,7 +83,7 @@ private sealed class MemberInfoReference : IObjectReference
 
             private static BindingFlags GetBindingAttr(MemberInfo member)
             {
-                if (member == null) throw new ArgumentNullException(nameof(member));
+                if (member is null) throw new ArgumentNullException(nameof(member));
                 var bindingFlags = default(BindingFlags);
                 switch (member)
                 {
@@ -144,7 +144,7 @@ public object GetRealObject(StreamingContext context)
                 if (MemberType == MemberTypes.Method || MemberType == MemberTypes.Constructor)
                 {
                     var methods = DeclaringType.GetMember(Name, MemberType, BindingAttr | BindingFlags.DeclaredOnly);
-                    if (Parameters.Any(t => t == null))
+                    if (Parameters.Any(t => t is null))
                         throw new ArgumentException("Detected null argument type in the method signature.",
                             nameof(Parameters));
                     if (Parameters.Any(t => t.IsGenericParameter))
diff --git a/src/FluentNHibernate/Mapping/Access.cs b/src/FluentNHibernate/Mapping/Access.cs
index 4b849a852..b83eec214 100644
--- a/src/FluentNHibernate/Mapping/Access.cs
+++ b/src/FluentNHibernate/Mapping/Access.cs
@@ -109,7 +109,7 @@ public bool Equals(Access other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public static bool operator ==(Access x, Access y)
diff --git a/src/FluentNHibernate/Mapping/AnyPart.cs b/src/FluentNHibernate/Mapping/AnyPart.cs
index b49d5bd35..29e1485c9 100644
--- a/src/FluentNHibernate/Mapping/AnyPart.cs
+++ b/src/FluentNHibernate/Mapping/AnyPart.cs
@@ -34,7 +34,7 @@ public AnyPart(Type entity, Member member)
         cascade = new CascadeExpression<AnyPart<T>>(this, value =>
         {
             var current = attributes.Get("Cascade") as string;
-            attributes.Set("Cascade", Layer.UserSupplied, current == null ? value : string.Format("{0},{1}", current, value));
+            attributes.Set("Cascade", Layer.UserSupplied, current is null ? value : string.Format("{0},{1}", current, value));
         });
 
         SetDefaultAccess();
diff --git a/src/FluentNHibernate/Mapping/ClassMap.cs b/src/FluentNHibernate/Mapping/ClassMap.cs
index e2ad6e098..79f27c0e7 100644
--- a/src/FluentNHibernate/Mapping/ClassMap.cs
+++ b/src/FluentNHibernate/Mapping/ClassMap.cs
@@ -104,7 +104,7 @@ public IdentityPart Id(Expression<Func<T, object>> memberExpression, string colu
 
         var part = new IdentityPart(EntityType, member);
 
-        if (column != null)
+        if (column is not null)
             part.Column(column);
 
         providers.Id = part;
@@ -145,7 +145,7 @@ public IdentityPart Id<TId>(string column)
     {
         var part = new IdentityPart(typeof(T), typeof(TId));
 
-        if (column != null)
+        if (column is not null)
         {
             part.SetName(column);
             part.Column(column);
@@ -618,7 +618,7 @@ ClassMapping IMappingProvider.GetClassMapping()
         mapping.Set(x => x.Type, Layer.Defaults, typeof(T));
         mapping.Set(x => x.Name, Layer.Defaults, typeof(T).AssemblyQualifiedName);
 
-        if (providers.Version != null)
+        if (providers.Version is not null)
             mapping.Set(x => x.Version, Layer.Defaults, providers.Version.GetVersionMapping());
 
         foreach (var provider in providers.OrderedProviders) {
diff --git a/src/FluentNHibernate/Mapping/ClasslikeMapBase.cs b/src/FluentNHibernate/Mapping/ClasslikeMapBase.cs
index 7c82218e8..81a8b8bce 100644
--- a/src/FluentNHibernate/Mapping/ClasslikeMapBase.cs
+++ b/src/FluentNHibernate/Mapping/ClasslikeMapBase.cs
@@ -126,7 +126,7 @@ ManyToOnePart<TOther> References<TOther>(Member member, string columnName)
 
         var part = new ManyToOnePart<TOther>(EntityType, member);
 
-        if (columnName != null)
+        if (columnName is not null)
             part.Column(columnName);
 
         providers.References.Add(part);
@@ -294,7 +294,7 @@ ComponentPart<TComponent> Component<TComponent>(Member member, Action<ComponentP
 
         var part = new ComponentPart<TComponent>(typeof(T), member);
 
-        if (action != null) action(part);
+        if (action is not null) action(part);
 
         providers.Components.Add(part);
 
diff --git a/src/FluentNHibernate/Mapping/ComponentPartBase.cs b/src/FluentNHibernate/Mapping/ComponentPartBase.cs
index a6842ce84..a1f1dd349 100644
--- a/src/FluentNHibernate/Mapping/ComponentPartBase.cs
+++ b/src/FluentNHibernate/Mapping/ComponentPartBase.cs
@@ -28,7 +28,7 @@ protected ComponentPartBase(AttributeStore attributes, Member member, MappingPro
         this.member = member;
         this.providers = providers;
 
-        if (member != null)
+        if (member is not null)
             SetDefaultAccess();
     }
 
@@ -168,7 +168,7 @@ protected ComponentMapping CreateComponentMapping()
     {
         var mapping = CreateComponentMappingRoot(attributes.Clone());
 
-        if (member != null)
+        if (member is not null)
             mapping.Set(x => x.Name, Layer.Defaults, member.Name);
 
         foreach (var property in providers.Properties)
diff --git a/src/FluentNHibernate/Mapping/CompositeElementPart.cs b/src/FluentNHibernate/Mapping/CompositeElementPart.cs
index a5b01b874..9a6b5e4e2 100644
--- a/src/FluentNHibernate/Mapping/CompositeElementPart.cs
+++ b/src/FluentNHibernate/Mapping/CompositeElementPart.cs
@@ -102,7 +102,7 @@ protected virtual ManyToOnePart<TOther> References<TOther>(Member property, stri
     {
         var part = new ManyToOnePart<TOther>(typeof(T), property);
 
-        if (columnName != null)
+        if (columnName is not null)
             part.Column(columnName);
 
         references.Add(part);
diff --git a/src/FluentNHibernate/Mapping/CompositeIdentityPart.cs b/src/FluentNHibernate/Mapping/CompositeIdentityPart.cs
index d47acd26d..9202156d8 100644
--- a/src/FluentNHibernate/Mapping/CompositeIdentityPart.cs
+++ b/src/FluentNHibernate/Mapping/CompositeIdentityPart.cs
@@ -84,7 +84,7 @@ protected virtual CompositeIdentityPart<T> KeyProperty(Member member, string col
         key.Set(x => x.Name, Layer.Defaults, member.Name);
         key.Set(x => x.Type, Layer.Defaults, new TypeReference(type));
 
-        if (customMapping != null)
+        if (customMapping is not null)
         {
             var part = new KeyPropertyPart(key);
             customMapping(part);
@@ -162,7 +162,7 @@ protected virtual CompositeIdentityPart<T> KeyReference(Member member, IEnumerab
 
         var keyPart = new KeyManyToOnePart(key);
 
-        if (customMapping != null)
+        if (customMapping is not null)
             customMapping(keyPart);
 
         keys.Add(key);            
@@ -173,7 +173,7 @@ protected virtual CompositeIdentityPart<T> KeyReference(Member member, IEnumerab
     public virtual CompositeIdentityPart<T> CustomType<CType>()
     {
         var key = keys.Where(x => x is KeyPropertyMapping).Cast<KeyPropertyMapping>().LastOrDefault();
-        if (key != null)
+        if (key is not null)
         {
             key.Set(x => x.Type, Layer.Defaults, new TypeReference(typeof(CType)));
         }
diff --git a/src/FluentNHibernate/Mapping/FilterDefinition.cs b/src/FluentNHibernate/Mapping/FilterDefinition.cs
index 2c0596f7a..40277ad9a 100644
--- a/src/FluentNHibernate/Mapping/FilterDefinition.cs
+++ b/src/FluentNHibernate/Mapping/FilterDefinition.cs
@@ -41,7 +41,7 @@ public FilterDefinition WithCondition(string condition)
     public FilterDefinition AddParameter(string name, IType type)
     {
         if (string.IsNullOrEmpty(name)) throw new ArgumentException("The name is mandatory", "name");
-        if (type == null) throw new ArgumentNullException("type");
+        if (type is null) throw new ArgumentNullException("type");
         parameters.Add(name, type);
         return this;
     }
diff --git a/src/FluentNHibernate/Mapping/FilterPart.cs b/src/FluentNHibernate/Mapping/FilterPart.cs
index 0cc007c98..53836d571 100644
--- a/src/FluentNHibernate/Mapping/FilterPart.cs
+++ b/src/FluentNHibernate/Mapping/FilterPart.cs
@@ -62,9 +62,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (filterName != null ? filterName.GetHashCode() : 0);
-            result = (result * 397) ^ (condition != null ? condition.GetHashCode() : 0);
-            result = (result * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+            int result = (filterName is not null ? filterName.GetHashCode() : 0);
+            result = (result * 397) ^ (condition is not null ? condition.GetHashCode() : 0);
+            result = (result * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/Mapping/HibernateMappingPart.cs b/src/FluentNHibernate/Mapping/HibernateMappingPart.cs
index df19db140..a193925c4 100644
--- a/src/FluentNHibernate/Mapping/HibernateMappingPart.cs
+++ b/src/FluentNHibernate/Mapping/HibernateMappingPart.cs
@@ -16,7 +16,7 @@ public HibernateMappingPart()
         defaultCascade = new CascadeExpression<HibernateMappingPart>(this, value =>
         {
             var current = attributes.Get("DefaultCascade") as string;
-            attributes.Set("DefaultCascade", Layer.UserSupplied, current == null ? value : string.Format("{0},{1}", current, value));
+            attributes.Set("DefaultCascade", Layer.UserSupplied, current is null ? value : string.Format("{0},{1}", current, value));
         });
         defaultAccess = new AccessStrategyBuilder<HibernateMappingPart>(this, value => attributes.Set("DefaultAccess", Layer.UserSupplied, value));
     }
diff --git a/src/FluentNHibernate/Mapping/IdentityPart.cs b/src/FluentNHibernate/Mapping/IdentityPart.cs
index 284328379..7167b934e 100644
--- a/src/FluentNHibernate/Mapping/IdentityPart.cs
+++ b/src/FluentNHibernate/Mapping/IdentityPart.cs
@@ -292,7 +292,7 @@ IdMapping IIdentityMappingProvider.GetIdentityMapping()
             mapping.AddColumn(Layer.Defaults, columnMapping);
         }
 
-        if (member != null)
+        if (member is not null)
             mapping.Set(x => x.Name, Layer.Defaults, name);
 
         mapping.Set(x => x.Type, Layer.Defaults, new TypeReference(identityType));
diff --git a/src/FluentNHibernate/Mapping/Laziness.cs b/src/FluentNHibernate/Mapping/Laziness.cs
index 0f8a8388e..a6d7ba8ea 100644
--- a/src/FluentNHibernate/Mapping/Laziness.cs
+++ b/src/FluentNHibernate/Mapping/Laziness.cs
@@ -41,7 +41,7 @@ public bool Equals(Laziness other)
 
     public override int GetHashCode()
     {
-        return (value != null ? value.GetHashCode() : 0);
+        return (value is not null ? value.GetHashCode() : 0);
     }
 
     public override string ToString()
diff --git a/src/FluentNHibernate/Mapping/ManyToManyPart.cs b/src/FluentNHibernate/Mapping/ManyToManyPart.cs
index 3be62c9e5..67b9f2912 100644
--- a/src/FluentNHibernate/Mapping/ManyToManyPart.cs
+++ b/src/FluentNHibernate/Mapping/ManyToManyPart.cs
@@ -125,7 +125,7 @@ public ManyToManyPart<TChild> AsTernaryAssociation(string indexColumn, string va
         manyToManyIndex.Column(indexColumn);
         manyToManyIndex.Type(indexType);
 
-        if (indexAction != null)
+        if (indexAction is not null)
             indexAction(manyToManyIndex);
 
         ChildKeyColumn(valueColumn);
@@ -154,7 +154,7 @@ public ManyToManyPart<TChild> AsTernaryAssociation(Type indexType, string indexC
         manyToManyIndex.Column(indexColumn);
         manyToManyIndex.Type(indexType);
 
-        if (indexAction != null)
+        if (indexAction is not null)
             indexAction(manyToManyIndex);
 
         ChildKeyColumn(valueColumn);
@@ -223,7 +223,7 @@ protected override ICollectionRelationshipMapping GetRelationship()
             ContainingEntityType = EntityType,
         };
 
-        if (isTernary && valueType != null)
+        if (isTernary && valueType is not null)
             mapping.Set(x => x.Class, Layer.Defaults, new TypeReference(valueType));
 
         foreach (var filterPart in childFilters)
@@ -371,7 +371,7 @@ protected override CollectionMapping GetCollectionMapping()
         foreach (var column in parentKeyColumns)
             collection.Key.AddColumn(Layer.UserSupplied, column.Clone());
 
-        if (collection.Relationship != null)
+        if (collection.Relationship is not null)
         {
             // child columns
             if (childKeyColumns.Count == 0)
@@ -382,7 +382,7 @@ protected override CollectionMapping GetCollectionMapping()
         }
 
         // HACK: Index only on list and map - shouldn't have to do this!
-        if (index != null)
+        if (index is not null)
         {
 #pragma warning disable 612,618
             collection.Set(x => x.Index, Layer.Defaults, index.GetIndexMapping());
@@ -390,7 +390,7 @@ protected override CollectionMapping GetCollectionMapping()
         }
 
         // HACK: shouldn't have to do this!
-        if (manyToManyIndex != null && collection.Collection == Collection.Map)
+        if (manyToManyIndex is not null && collection.Collection == Collection.Map)
 #pragma warning disable 612,618
             collection.Set(x => x.Index, Layer.Defaults, manyToManyIndex.GetIndexMapping());
 #pragma warning restore 612,618
diff --git a/src/FluentNHibernate/Mapping/ManyToOnePart.cs b/src/FluentNHibernate/Mapping/ManyToOnePart.cs
index ed98b829e..96c3d597b 100644
--- a/src/FluentNHibernate/Mapping/ManyToOnePart.cs
+++ b/src/FluentNHibernate/Mapping/ManyToOnePart.cs
@@ -30,7 +30,7 @@ public ManyToOnePart(Type entity, Member member)
         cascade = new CascadeExpression<ManyToOnePart<TOther>>(this, value =>
         {
             var current = attributes.Get("Cascade") as string;
-            attributes.Set("Cascade", Layer.UserSupplied, current == null ? value : string.Format("{0},{1}", current, value));
+            attributes.Set("Cascade", Layer.UserSupplied, current is null ? value : string.Format("{0},{1}", current, value));
         });
         notFound = new NotFoundExpression<ManyToOnePart<TOther>>(this, value => attributes.Set("NotFound", Layer.UserSupplied, value));
 
diff --git a/src/FluentNHibernate/Mapping/Member.cs b/src/FluentNHibernate/Mapping/Member.cs
index 0f2baa622..d650adf94 100644
--- a/src/FluentNHibernate/Mapping/Member.cs
+++ b/src/FluentNHibernate/Mapping/Member.cs
@@ -76,7 +76,7 @@ public override object GetValue(object target)
 
     public override bool TryGetBackingField(out Member field)
     {
-        if (backingField != null)
+        if (backingField is not null)
         {
             field = backingField;
             return true;
@@ -91,7 +91,7 @@ public override bool TryGetBackingField(out Member field)
         reflectedField = reflectedField ?? DeclaringType.GetField("_" + name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
         reflectedField = reflectedField ?? DeclaringType.GetField("m_" + name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
 
-        if (reflectedField == null)
+        if (reflectedField is null)
         {
             field = null;
             return false;
@@ -290,7 +290,7 @@ public PropertyMember(PropertyInfo member)
 
     MethodMember GetMember(MethodInfo method)
     {
-        if (method == null)
+        if (method is null)
             return null;
 
         return (MethodMember)method.ToMember();
@@ -308,7 +308,7 @@ public override object GetValue(object target)
 
     public override bool TryGetBackingField(out Member field)
     {
-        if (backingField != null)
+        if (backingField is not null)
         {
             field = backingField;
             return true;
@@ -318,7 +318,7 @@ public override bool TryGetBackingField(out Member field)
         reflectedField = reflectedField ?? DeclaringType.GetField("_" + Name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
         reflectedField = reflectedField ?? DeclaringType.GetField("m_" + Name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
 
-        if (reflectedField == null)
+        if (reflectedField is null)
         {
             field = null;
             return false;
@@ -343,7 +343,7 @@ public override bool CanWrite
             // override the default reflection value here. Private setters aren't
             // considered "settable" in the same sense that public ones are. We can
             // use this to control the access strategy later
-            if (IsAutoProperty && (setMethod == null || setMethod.IsPrivate))
+            if (IsAutoProperty && (setMethod is null || setMethod.IsPrivate))
                 return false;
 
             return member.CanWrite;
@@ -378,8 +378,8 @@ public override bool IsAutoProperty
     {
         get
         {
-            return (getMethod != null && getMethod.IsCompilerGenerated) 
-                   || (setMethod != null && setMethod.IsCompilerGenerated);
+            return (getMethod is not null && getMethod.IsCompilerGenerated) 
+                   || (setMethod is not null && setMethod.IsCompilerGenerated);
         }
     }
 
@@ -423,7 +423,7 @@ public static class MemberExtensions
 {
     public static Member ToMember(this PropertyInfo propertyInfo)
     {
-        if (propertyInfo == null)
+        if (propertyInfo is null)
             throw new NullReferenceException("Cannot create member from null.");
             
         return new PropertyMember(propertyInfo);
@@ -431,7 +431,7 @@ public static Member ToMember(this PropertyInfo propertyInfo)
 
     public static Member ToMember(this MethodInfo methodInfo)
     {
-        if (methodInfo == null)
+        if (methodInfo is null)
             throw new NullReferenceException("Cannot create member from null.");
 
         return new MethodMember(methodInfo);
@@ -439,7 +439,7 @@ public static Member ToMember(this MethodInfo methodInfo)
 
     public static Member ToMember(this FieldInfo fieldInfo)
     {
-        if (fieldInfo == null)
+        if (fieldInfo is null)
             throw new NullReferenceException("Cannot create member from null.");
 
         return new FieldMember(fieldInfo);
@@ -447,7 +447,7 @@ public static Member ToMember(this FieldInfo fieldInfo)
 
     public static Member ToMember(this MemberInfo memberInfo)
     {
-        if (memberInfo == null)
+        if (memberInfo is null)
             throw new NullReferenceException("Cannot create member from null.");
 
         if (memberInfo is PropertyInfo)
@@ -488,7 +488,7 @@ public static IEnumerable<Member> GetInstanceMembers(this Type type)
         type.GetInstanceFields().Each(x => members.Add(x));
         type.GetInstanceMethods().Each(x => members.Add(x));
 
-        if (type.BaseType != null && type.BaseType != typeof(object))
+        if (type.BaseType is not null && type.BaseType != typeof(object))
             type.BaseType.GetInstanceMembers().Each(x => members.Add(x));
 
         return members;
diff --git a/src/FluentNHibernate/Mapping/MemberAccessResolver.cs b/src/FluentNHibernate/Mapping/MemberAccessResolver.cs
index d96970c69..772119902 100644
--- a/src/FluentNHibernate/Mapping/MemberAccessResolver.cs
+++ b/src/FluentNHibernate/Mapping/MemberAccessResolver.cs
@@ -8,7 +8,7 @@ public static Access Resolve(Member member)
         {
             var property = (PropertyMember)member;
                 
-            if (property.Set != null && !(property.Set.IsPrivate || property.Set.IsInternal))
+            if (property.Set is not null && !(property.Set.IsPrivate || property.Set.IsInternal))
                 return Access.Property;
 
             return Access.BackField;
@@ -18,7 +18,7 @@ public static Access Resolve(Member member)
         {
             var property = (PropertyMember)member;
 
-            if (property.Set != null && !(property.Set.IsPrivate || property.Set.IsInternal))
+            if (property.Set is not null && !(property.Set.IsPrivate || property.Set.IsInternal))
                 return Access.Property;
 
             Member backingField;
diff --git a/src/FluentNHibernate/Mapping/NamingStrategy.cs b/src/FluentNHibernate/Mapping/NamingStrategy.cs
index b534be845..1e799a8a6 100644
--- a/src/FluentNHibernate/Mapping/NamingStrategy.cs
+++ b/src/FluentNHibernate/Mapping/NamingStrategy.cs
@@ -37,7 +37,7 @@ public bool Equals(NamingStrategy other)
 
     public override int GetHashCode()
     {
-        return (strategy != null ? strategy.GetHashCode() : 0);
+        return (strategy is not null ? strategy.GetHashCode() : 0);
     }
 
     public override string ToString()
diff --git a/src/FluentNHibernate/Mapping/OneToManyPart.cs b/src/FluentNHibernate/Mapping/OneToManyPart.cs
index 8bb0590ad..7459ecf83 100644
--- a/src/FluentNHibernate/Mapping/OneToManyPart.cs
+++ b/src/FluentNHibernate/Mapping/OneToManyPart.cs
@@ -202,7 +202,7 @@ protected override CollectionMapping GetCollectionMapping()
         }
 
         // HACK: shouldn't have to do this!
-        if (manyToManyIndex != null && collection.Collection == Collection.Map)
+        if (manyToManyIndex is not null && collection.Collection == Collection.Map)
 #pragma warning disable 612,618
             collection.Set(x => x.Index, Layer.Defaults, manyToManyIndex.GetIndexMapping());
 #pragma warning restore 612,618
@@ -217,7 +217,7 @@ protected override ICollectionRelationshipMapping GetRelationship()
             ContainingEntityType = entity
         };
 
-        if (isTernary && valueType != null)
+        if (isTernary && valueType is not null)
             mapping.Set(x => x.Class, Layer.Defaults, new TypeReference(valueType));
 
         return mapping;
diff --git a/src/FluentNHibernate/Mapping/OneToOnePart.cs b/src/FluentNHibernate/Mapping/OneToOnePart.cs
index a1ea57d7b..633c237f0 100644
--- a/src/FluentNHibernate/Mapping/OneToOnePart.cs
+++ b/src/FluentNHibernate/Mapping/OneToOnePart.cs
@@ -24,7 +24,7 @@ public OneToOnePart(Type entity, Member member)
         cascade = new CascadeExpression<OneToOnePart<TOther>>(this, value =>
         {
             var current = attributes.Get("Cascade") as string;
-            attributes.Set("Cascade", Layer.UserSupplied, current == null ? value : string.Format("{0},{1}", current, value));
+            attributes.Set("Cascade", Layer.UserSupplied, current is null ? value : string.Format("{0},{1}", current, value));
         });
         this.entity = entity;
         this.member = member;
diff --git a/src/FluentNHibernate/Mapping/SubClassPart.cs b/src/FluentNHibernate/Mapping/SubClassPart.cs
index 564e67bba..a9f0950cf 100644
--- a/src/FluentNHibernate/Mapping/SubClassPart.cs
+++ b/src/FluentNHibernate/Mapping/SubClassPart.cs
@@ -34,7 +34,7 @@ SubclassMapping ISubclassMappingProvider.GetSubclassMapping()
     {
         var mapping = new SubclassMapping(SubclassType.Subclass, attributes.Clone());
 
-        if (discriminatorValue != null)
+        if (discriminatorValue is not null)
             mapping.Set(x => x.DiscriminatorValue, Layer.Defaults, discriminatorValue);
 
         mapping.Set(x => x.Type, Layer.Defaults, typeof(TSubclass));
diff --git a/src/FluentNHibernate/Mapping/SubclassMap.cs b/src/FluentNHibernate/Mapping/SubclassMap.cs
index 2f47529d7..29fdf0af8 100644
--- a/src/FluentNHibernate/Mapping/SubclassMap.cs
+++ b/src/FluentNHibernate/Mapping/SubclassMap.cs
@@ -293,7 +293,7 @@ SubclassMapping IIndeterminateSubclassMappingProvider.GetSubclassMapping(Subclas
         // TODO: un-hardcode this
         Type baseType = typeof(T).BaseType
                         ?? attributes.Get("Extends") as Type;
-        if (baseType != null)
+        if (baseType is not null)
         {
             var key = new KeyMapping();
             key.AddColumn(Layer.Defaults, new ColumnMapping(baseType.Name + "_id"));
diff --git a/src/FluentNHibernate/Mapping/ToManyBase.cs b/src/FluentNHibernate/Mapping/ToManyBase.cs
index 1d31a91d5..f761ebe32 100644
--- a/src/FluentNHibernate/Mapping/ToManyBase.cs
+++ b/src/FluentNHibernate/Mapping/ToManyBase.cs
@@ -39,7 +39,7 @@ protected ToManyBase(Type entity, Member member, Type type)
         cascade = new CollectionCascadeExpression<T>((T)this, value =>
         {
             var current = collectionAttributes.Get("Cascade") as string;
-            collectionAttributes.Set("Cascade", Layer.UserSupplied, current == null ? value : string.Format("{0},{1}", current, value));
+            collectionAttributes.Set("Cascade", Layer.UserSupplied, current is null ? value : string.Format("{0},{1}", current, value));
         });
 
         SetDefaultCollectionType();
@@ -405,7 +405,7 @@ private void CreateIndexMapping(Action<IndexPart> customIndex)
     {
         var indexPart = new IndexPart(typeof(T));
 
-        if (customIndex != null)
+        if (customIndex is not null)
             customIndex(indexPart);
 
 #pragma warning disable 612,618
@@ -418,7 +418,7 @@ private void CreateListIndexMapping(Action<ListIndexPart> customIndex)
         indexMapping = new IndexMapping();
         var builder = new ListIndexPart(indexMapping);
 
-        if (customIndex != null)
+        if (customIndex is not null)
             customIndex(builder);
     }
 
@@ -445,7 +445,7 @@ public T Element(string columnName)
     public T Element(string columnName, Action<ElementPart> customElementMapping)
     {
         Element(columnName);
-        if (customElementMapping != null) customElementMapping(elementPart);
+        if (customElementMapping is not null) customElementMapping(elementPart);
         return (T)this;
     }
 
@@ -737,7 +737,7 @@ protected virtual CollectionMapping GetCollectionMapping()
         if (Cache.IsDirty)
             mapping.Set(x => x.Cache, Layer.Defaults, ((ICacheMappingProvider)Cache).GetCacheMapping());
 
-        if (componentMapping != null)
+        if (componentMapping is not null)
         {
             mapping.Set(x => x.CompositeElement, Layer.Defaults, componentMapping.GetCompositeElementMapping());
             mapping.Set(x => x.Relationship, Layer.Defaults, null); // HACK: bad design
@@ -747,7 +747,7 @@ protected virtual CollectionMapping GetCollectionMapping()
         if (mapping.Collection == Collection.Array || mapping.Collection == Collection.List || mapping.Collection == Collection.Map)
             mapping.Set(x => x.Index, Layer.Defaults, indexMapping);
 
-        if (elementPart != null)
+        if (elementPart is not null)
         {
             mapping.Set(x => x.Element, Layer.Defaults, ((IElementMappingProvider)elementPart).GetElementMapping());
             mapping.Set(x => x.Relationship, Layer.Defaults, null); // HACK: bad design
diff --git a/src/FluentNHibernate/MappingModel/AnyMapping.cs b/src/FluentNHibernate/MappingModel/AnyMapping.cs
index 547c0b0fd..3870351cc 100644
--- a/src/FluentNHibernate/MappingModel/AnyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/AnyMapping.cs
@@ -134,11 +134,11 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (typeColumns != null ? typeColumns.GetHashCode() : 0);
-            result = (result * 397) ^ (identifierColumns != null ? identifierColumns.GetHashCode() : 0);
-            result = (result * 397) ^ (metaValues != null ? metaValues.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (typeColumns is not null ? typeColumns.GetHashCode() : 0);
+            result = (result * 397) ^ (identifierColumns is not null ? identifierColumns.GetHashCode() : 0);
+            result = (result * 397) ^ (metaValues is not null ? metaValues.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/AttributeStore.cs b/src/FluentNHibernate/MappingModel/AttributeStore.cs
index f8cf36c73..42c49289f 100644
--- a/src/FluentNHibernate/MappingModel/AttributeStore.cs
+++ b/src/FluentNHibernate/MappingModel/AttributeStore.cs
@@ -52,7 +52,7 @@ public AttributeStore Clone()
 
     public bool Equals(AttributeStore other)
     {
-        if (other == null) return false;
+        if (other is null) return false;
 
         return other.layeredValues.ContentEquals(layeredValues);
     }
@@ -68,7 +68,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((layeredValues != null ? layeredValues.GetHashCode() : 0) * 397);
+            return ((layeredValues is not null ? layeredValues.GetHashCode() : 0) * 397);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/CacheMapping.cs b/src/FluentNHibernate/MappingModel/CacheMapping.cs
index 8296605dd..0d955b537 100644
--- a/src/FluentNHibernate/MappingModel/CacheMapping.cs
+++ b/src/FluentNHibernate/MappingModel/CacheMapping.cs
@@ -60,7 +60,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^ (ContainedEntityType != null ? ContainedEntityType.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^ (ContainedEntityType is not null ? ContainedEntityType.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ClassMapping.cs b/src/FluentNHibernate/MappingModel/ClassBased/ClassMapping.cs
index 21f771bfa..9bc8c264f 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ClassMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ClassMapping.cs
@@ -70,22 +70,22 @@ public override void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessClass(this);            
 
-        if (Id != null)
+        if (Id is not null)
             visitor.Visit(Id);
 
-        if (NaturalId != null)
+        if (NaturalId is not null)
             visitor.Visit(NaturalId);
 
-        if (Discriminator != null)
+        if (Discriminator is not null)
             visitor.Visit(Discriminator);
 
-        if (Cache != null)
+        if (Cache is not null)
             visitor.Visit(Cache);
 
-        if (Version != null)
+        if (Version is not null)
             visitor.Visit(Version);
 
-        if (Tuplizer != null)
+        if (Tuplizer is not null)
             visitor.Visit(Tuplizer);
 
         base.AcceptVisitor(visitor);
@@ -204,7 +204,7 @@ public override bool Equals(object obj)
 
     public override int GetHashCode()
     {
-        return (attributes != null ? attributes.GetHashCode() : 0);
+        return (attributes is not null ? attributes.GetHashCode() : 0);
     }
 
     public void Set<T>(Expression<Func<ClassMapping, T>> expression, int layer, T value)
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ClassMappingBase.cs b/src/FluentNHibernate/MappingModel/ClassBased/ClassMappingBase.cs
index fd9aa1c09..2a901e3ba 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ClassMappingBase.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ClassMappingBase.cs
@@ -197,7 +197,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((mappedMembers != null ? mappedMembers.GetHashCode() : 0) * 397) ^ (subclasses != null ? subclasses.GetHashCode() : 0);
+            return ((mappedMembers is not null ? mappedMembers.GetHashCode() : 0) * 397) ^ (subclasses is not null ? subclasses.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ComponentMapping.cs b/src/FluentNHibernate/MappingModel/ClassBased/ComponentMapping.cs
index c1fe1f516..24d86d12b 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ComponentMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ComponentMapping.cs
@@ -75,7 +75,7 @@ public override int GetHashCode()
         unchecked
         {
             {
-                return (base.GetHashCode() * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+                return (base.GetHashCode() * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
             }
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ComponentMappingBase.cs b/src/FluentNHibernate/MappingModel/ClassBased/ComponentMappingBase.cs
index edc4f7be3..a357a3811 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ComponentMappingBase.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ComponentMappingBase.cs
@@ -20,7 +20,7 @@ protected ComponentMappingBase(AttributeStore attributes)
 
     public override void AcceptVisitor(IMappingModelVisitor visitor)
     {
-        if (Parent != null)
+        if (Parent is not null)
             visitor.Visit(Parent);
 
         base.AcceptVisitor(visitor);
@@ -81,9 +81,9 @@ public override int GetHashCode()
         unchecked
         {
             int result = base.GetHashCode();
-            result = (result * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
-            result = (result * 397) ^ (Member != null ? Member.GetHashCode() : 0);
+            result = (result * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
+            result = (result * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ComponentType.cs b/src/FluentNHibernate/MappingModel/ClassBased/ComponentType.cs
index 1e3a38629..5595e52cb 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ComponentType.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ComponentType.cs
@@ -40,7 +40,7 @@ public bool Equals(ComponentType other)
 
     public override int GetHashCode()
     {
-        return (elementName != null ? elementName.GetHashCode() : 0);
+        return (elementName is not null ? elementName.GetHashCode() : 0);
     }
 
     public static bool operator ==(ComponentType left, ComponentType right)
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/ReferenceComponentMapping.cs b/src/FluentNHibernate/MappingModel/ClassBased/ReferenceComponentMapping.cs
index 6985492ea..3d4884783 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/ReferenceComponentMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/ReferenceComponentMapping.cs
@@ -31,7 +31,7 @@ public void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessComponent(this);
 
-        if (mergedComponent != null)
+        if (mergedComponent is not null)
             mergedComponent.AcceptVisitor(visitor);
     }
 
@@ -125,7 +125,7 @@ public Type ContainingEntityType
 
     public Member Member
     {
-        get { return (mergedComponent == null) ? property : mergedComponent.Member; }
+        get { return (mergedComponent is null) ? property : mergedComponent.Member; }
     }
 
     public ParentMapping Parent
@@ -167,12 +167,12 @@ public bool OptimisticLock
 
     public string Name
     {
-        get { return (mergedComponent == null) ? property.Name : mergedComponent.Name; }
+        get { return (mergedComponent is null) ? property.Name : mergedComponent.Name; }
     }
 
     public Type Type
     {
-        get { return (mergedComponent == null) ? componentType : mergedComponent.Type; }
+        get { return (mergedComponent is null) ? componentType : mergedComponent.Type; }
     }
 
     public TypeReference Class
@@ -187,7 +187,7 @@ public bool Lazy
 
     public bool IsAssociated
     {
-        get { return mergedComponent != null; }
+        get { return mergedComponent is not null; }
     }
 
     public ComponentMapping MergedModel
@@ -217,10 +217,10 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (property != null ? property.GetHashCode() : 0);
-            result = (result * 397) ^ (componentType != null ? componentType.GetHashCode() : 0);
-            result = (result * 397) ^ (mergedComponent != null ? mergedComponent.GetHashCode() : 0);
-            result = (result * 397) ^ (containingEntityType != null ? containingEntityType.GetHashCode() : 0);
+            int result = (property is not null ? property.GetHashCode() : 0);
+            result = (result * 397) ^ (componentType is not null ? componentType.GetHashCode() : 0);
+            result = (result * 397) ^ (mergedComponent is not null ? mergedComponent.GetHashCode() : 0);
+            result = (result * 397) ^ (containingEntityType is not null ? containingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/SubclassMapping.cs b/src/FluentNHibernate/MappingModel/ClassBased/SubclassMapping.cs
index 154879ebf..39024e644 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/SubclassMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/SubclassMapping.cs
@@ -37,7 +37,7 @@ public override void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessSubclass(this);
 
-        if (SubclassType == SubclassType.JoinedSubclass && Key != null)
+        if (SubclassType == SubclassType.JoinedSubclass && Key is not null)
             visitor.Visit(Key);
 
         base.AcceptVisitor(visitor);
@@ -152,7 +152,7 @@ public override int GetHashCode()
         unchecked
         {
             {
-                return (base.GetHashCode() * 397) ^ (attributes != null
+                return (base.GetHashCode() * 397) ^ (attributes is not null
                     ? attributes.GetHashCode()
                     : 0);
             }
diff --git a/src/FluentNHibernate/MappingModel/ClassBased/SubclassType.cs b/src/FluentNHibernate/MappingModel/ClassBased/SubclassType.cs
index 0215d2bd2..b1e51d7b7 100644
--- a/src/FluentNHibernate/MappingModel/ClassBased/SubclassType.cs
+++ b/src/FluentNHibernate/MappingModel/ClassBased/SubclassType.cs
@@ -36,7 +36,7 @@ public override bool Equals(object obj)
 
     public override int GetHashCode()
     {
-        return (elementName != null ? elementName.GetHashCode() : 0);
+        return (elementName is not null ? elementName.GetHashCode() : 0);
     }
 
     public override string ToString()
diff --git a/src/FluentNHibernate/MappingModel/Collections/CollectionMapping.cs b/src/FluentNHibernate/MappingModel/Collections/CollectionMapping.cs
index f15161894..adccd98df 100644
--- a/src/FluentNHibernate/MappingModel/Collections/CollectionMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/CollectionMapping.cs
@@ -35,25 +35,25 @@ public override void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessCollection(this);
 
-        if (Key != null)
+        if (Key is not null)
             visitor.Visit(Key);
 
-        if (Index != null && (Collection == Collection.Array || Collection == Collection.List || Collection == Collection.Map))
+        if (Index is not null && (Collection == Collection.Array || Collection == Collection.List || Collection == Collection.Map))
             visitor.Visit(Index);
 
-        if (Element != null)
+        if (Element is not null)
             visitor.Visit(Element);
 
-        if (CompositeElement != null)
+        if (CompositeElement is not null)
             visitor.Visit(CompositeElement);
 
-        if (Relationship != null)
+        if (Relationship is not null)
             visitor.Visit(Relationship);
 
         foreach (var filter in Filters)
             visitor.Visit(filter);
 
-        if (Cache != null)
+        if (Cache is not null)
             visitor.Visit(Cache);
     }
 
@@ -213,10 +213,10 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (filters != null ? filters.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
-            result = (result * 397) ^ (Member != null ? Member.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (filters is not null ? filters.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
+            result = (result * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/CompositeElementMapping.cs b/src/FluentNHibernate/MappingModel/Collections/CompositeElementMapping.cs
index cad241909..cae9b9a6f 100644
--- a/src/FluentNHibernate/MappingModel/Collections/CompositeElementMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/CompositeElementMapping.cs
@@ -27,7 +27,7 @@ public override void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessCompositeElement(this);
 
-        if (Parent != null)
+        if (Parent is not null)
             visitor.Visit(Parent);
 
         foreach (var compositeElement in CompositeElements)
@@ -97,9 +97,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (mappedMembers != null ? mappedMembers.GetHashCode() : 0);
-            result = (result * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (mappedMembers is not null ? mappedMembers.GetHashCode() : 0);
+            result = (result * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/ElementMapping.cs b/src/FluentNHibernate/MappingModel/Collections/ElementMapping.cs
index 362f82ea5..5b68a1364 100644
--- a/src/FluentNHibernate/MappingModel/Collections/ElementMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/ElementMapping.cs
@@ -77,9 +77,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/IndexManyToManyMapping.cs b/src/FluentNHibernate/MappingModel/Collections/IndexManyToManyMapping.cs
index ef51f392c..089e91d9d 100644
--- a/src/FluentNHibernate/MappingModel/Collections/IndexManyToManyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/IndexManyToManyMapping.cs
@@ -82,9 +82,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/IndexMapping.cs b/src/FluentNHibernate/MappingModel/Collections/IndexMapping.cs
index 4f7569853..e63af5866 100644
--- a/src/FluentNHibernate/MappingModel/Collections/IndexMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/IndexMapping.cs
@@ -77,9 +77,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/LayeredColumns.cs b/src/FluentNHibernate/MappingModel/Collections/LayeredColumns.cs
index 93fea08a6..17d20d3bc 100644
--- a/src/FluentNHibernate/MappingModel/Collections/LayeredColumns.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/LayeredColumns.cs
@@ -21,7 +21,7 @@ public IEnumerable<ColumnMapping> Columns
 
             foreach (var value in values)
             {
-                if (value == null)
+                if (value is null)
                     yield break;
 
                 yield return value;
diff --git a/src/FluentNHibernate/MappingModel/Collections/ManyToManyMapping.cs b/src/FluentNHibernate/MappingModel/Collections/ManyToManyMapping.cs
index 780d15b50..7d59cd56b 100644
--- a/src/FluentNHibernate/MappingModel/Collections/ManyToManyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/ManyToManyMapping.cs
@@ -131,9 +131,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Collections/OneToManyMapping.cs b/src/FluentNHibernate/MappingModel/Collections/OneToManyMapping.cs
index a458113cf..63f256f67 100644
--- a/src/FluentNHibernate/MappingModel/Collections/OneToManyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Collections/OneToManyMapping.cs
@@ -65,7 +65,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/ColumnBasedMappingBase.cs b/src/FluentNHibernate/MappingModel/ColumnBasedMappingBase.cs
index 6e843b9c5..26c0938a0 100644
--- a/src/FluentNHibernate/MappingModel/ColumnBasedMappingBase.cs
+++ b/src/FluentNHibernate/MappingModel/ColumnBasedMappingBase.cs
@@ -50,7 +50,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((columns != null ? columns.GetHashCode() : 0) * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+            return ((columns is not null ? columns.GetHashCode() : 0) * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
         }
     }
 }
diff --git a/src/FluentNHibernate/MappingModel/ColumnMapping.cs b/src/FluentNHibernate/MappingModel/ColumnMapping.cs
index a5590d78f..2c271e72d 100644
--- a/src/FluentNHibernate/MappingModel/ColumnMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ColumnMapping.cs
@@ -112,7 +112,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^ (Member != null ? Member.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/Conventions/ManyToManyTableConvention.cs b/src/FluentNHibernate/MappingModel/Conventions/ManyToManyTableConvention.cs
index efe3111e8..c5baece26 100644
--- a/src/FluentNHibernate/MappingModel/Conventions/ManyToManyTableConvention.cs
+++ b/src/FluentNHibernate/MappingModel/Conventions/ManyToManyTableConvention.cs
@@ -19,7 +19,7 @@
 //                m => m.ParentType == manyToManyMapping.ChildType && m.ChildType == manyToManyMapping.ParentType)
 //                .FirstOrDefault();
                 
-//            if(otherSide == null)
+//            if(otherSide is null)
 //                _foundMappings.Add(manyToManyMapping);
 //            else
 //            {
diff --git a/src/FluentNHibernate/MappingModel/DiscriminatorMapping.cs b/src/FluentNHibernate/MappingModel/DiscriminatorMapping.cs
index 4ca2a93a7..80c6a705e 100644
--- a/src/FluentNHibernate/MappingModel/DiscriminatorMapping.cs
+++ b/src/FluentNHibernate/MappingModel/DiscriminatorMapping.cs
@@ -66,7 +66,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0) * 397) ^ ((Columns != null ? Columns.GetHashCode() : 0) * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+            return ((ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0) * 397) ^ ((Columns is not null ? Columns.GetHashCode() : 0) * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/FilterDefinitionMapping.cs b/src/FluentNHibernate/MappingModel/FilterDefinitionMapping.cs
index 4efdd16df..824b45da5 100644
--- a/src/FluentNHibernate/MappingModel/FilterDefinitionMapping.cs
+++ b/src/FluentNHibernate/MappingModel/FilterDefinitionMapping.cs
@@ -63,7 +63,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^ (parameters != null ? parameters.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^ (parameters is not null ? parameters.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/FilterMapping.cs b/src/FluentNHibernate/MappingModel/FilterMapping.cs
index 8ec3b242d..021f8bea7 100644
--- a/src/FluentNHibernate/MappingModel/FilterMapping.cs
+++ b/src/FluentNHibernate/MappingModel/FilterMapping.cs
@@ -56,7 +56,7 @@ public override bool Equals(object obj)
 
     public override int GetHashCode()
     {
-        return (attributes != null ? attributes.GetHashCode() : 0);
+        return (attributes is not null ? attributes.GetHashCode() : 0);
     }
 
     public void Set<T>(Expression<Func<FilterMapping, T>> expression, int layer, T value)
diff --git a/src/FluentNHibernate/MappingModel/HibernateMapping.cs b/src/FluentNHibernate/MappingModel/HibernateMapping.cs
index 73c17132a..faecbd090 100644
--- a/src/FluentNHibernate/MappingModel/HibernateMapping.cs
+++ b/src/FluentNHibernate/MappingModel/HibernateMapping.cs
@@ -132,10 +132,10 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (classes != null ? classes.GetHashCode() : 0);
-            result = (result * 397) ^ (filters != null ? filters.GetHashCode() : 0);
-            result = (result * 397) ^ (imports != null ? imports.GetHashCode() : 0);
-            result = (result * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+            int result = (classes is not null ? classes.GetHashCode() : 0);
+            result = (result * 397) ^ (filters is not null ? filters.GetHashCode() : 0);
+            result = (result * 397) ^ (imports is not null ? imports.GetHashCode() : 0);
+            result = (result * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Identity/CompositeIdMapping.cs b/src/FluentNHibernate/MappingModel/Identity/CompositeIdMapping.cs
index e9d399f37..a29082315 100644
--- a/src/FluentNHibernate/MappingModel/Identity/CompositeIdMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Identity/CompositeIdMapping.cs
@@ -92,9 +92,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (keys != null ? keys.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (keys is not null ? keys.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Identity/GeneratorMapping.cs b/src/FluentNHibernate/MappingModel/Identity/GeneratorMapping.cs
index f74e915f8..e158cd20a 100644
--- a/src/FluentNHibernate/MappingModel/Identity/GeneratorMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Identity/GeneratorMapping.cs
@@ -50,9 +50,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (Params != null ? Params.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (Params is not null ? Params.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Identity/IdMapping.cs b/src/FluentNHibernate/MappingModel/Identity/IdMapping.cs
index 4bb8feba4..cdda4c9b7 100644
--- a/src/FluentNHibernate/MappingModel/Identity/IdMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Identity/IdMapping.cs
@@ -30,7 +30,7 @@ public override void AcceptVisitor(IMappingModelVisitor visitor)
         foreach (var column in Columns)
             visitor.Visit(column);
 
-        if (Generator != null)
+        if (Generator is not null)
             visitor.Visit(Generator);
     }
 
@@ -85,8 +85,8 @@ public override int GetHashCode()
         unchecked
         {
             int result = base.GetHashCode();
-            result = (result * 397) ^ (Member != null ? Member.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            result = (result * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Identity/KeyManyToOneMapping.cs b/src/FluentNHibernate/MappingModel/Identity/KeyManyToOneMapping.cs
index f25f6226e..dfb90db12 100644
--- a/src/FluentNHibernate/MappingModel/Identity/KeyManyToOneMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Identity/KeyManyToOneMapping.cs
@@ -91,9 +91,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/Identity/KeyPropertyMapping.cs b/src/FluentNHibernate/MappingModel/Identity/KeyPropertyMapping.cs
index 748a61b18..cc0f2b05e 100644
--- a/src/FluentNHibernate/MappingModel/Identity/KeyPropertyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/Identity/KeyPropertyMapping.cs
@@ -73,9 +73,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/ImportMapping.cs b/src/FluentNHibernate/MappingModel/ImportMapping.cs
index 767c29082..73a5017ba 100644
--- a/src/FluentNHibernate/MappingModel/ImportMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ImportMapping.cs
@@ -49,7 +49,7 @@ public override bool Equals(object obj)
 
     public override int GetHashCode()
     {
-        return (attributes != null ? attributes.GetHashCode() : 0);
+        return (attributes is not null ? attributes.GetHashCode() : 0);
     }
 
     public override bool IsSpecified(string attribute)
diff --git a/src/FluentNHibernate/MappingModel/JoinMapping.cs b/src/FluentNHibernate/MappingModel/JoinMapping.cs
index 76891f52b..24afb061b 100644
--- a/src/FluentNHibernate/MappingModel/JoinMapping.cs
+++ b/src/FluentNHibernate/MappingModel/JoinMapping.cs
@@ -126,7 +126,7 @@ public void AcceptVisitor(IMappingModelVisitor visitor)
     {
         visitor.ProcessJoin(this);
 
-        if (Key != null)
+        if (Key is not null)
             visitor.Visit(Key);
 
         mappedMembers.AcceptVisitor(visitor);
@@ -153,9 +153,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (mappedMembers != null ? mappedMembers.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (mappedMembers is not null ? mappedMembers.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/KeyMapping.cs b/src/FluentNHibernate/MappingModel/KeyMapping.cs
index 600c64e83..6d13b64fb 100644
--- a/src/FluentNHibernate/MappingModel/KeyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/KeyMapping.cs
@@ -97,9 +97,9 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/ManyToOneMapping.cs b/src/FluentNHibernate/MappingModel/ManyToOneMapping.cs
index caa3b70a8..498c2de06 100644
--- a/src/FluentNHibernate/MappingModel/ManyToOneMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ManyToOneMapping.cs
@@ -150,10 +150,10 @@ public override int GetHashCode()
     {
         unchecked
         {
-            int result = (attributes != null ? attributes.GetHashCode() : 0);
-            result = (result * 397) ^ (columns != null ? columns.GetHashCode() : 0);
-            result = (result * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
-            result = (result * 397) ^ (Member != null ? Member.GetHashCode() : 0);
+            int result = (attributes is not null ? attributes.GetHashCode() : 0);
+            result = (result * 397) ^ (columns is not null ? columns.GetHashCode() : 0);
+            result = (result * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
+            result = (result * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
             return result;
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/MetaValueMapping.cs b/src/FluentNHibernate/MappingModel/MetaValueMapping.cs
index 383c7f0cf..868220a04 100644
--- a/src/FluentNHibernate/MappingModel/MetaValueMapping.cs
+++ b/src/FluentNHibernate/MappingModel/MetaValueMapping.cs
@@ -51,8 +51,8 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^
-                   (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^
+                   (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/OneToOneMapping.cs b/src/FluentNHibernate/MappingModel/OneToOneMapping.cs
index 4bce068df..12c600381 100644
--- a/src/FluentNHibernate/MappingModel/OneToOneMapping.cs
+++ b/src/FluentNHibernate/MappingModel/OneToOneMapping.cs
@@ -94,7 +94,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/ParentMapping.cs b/src/FluentNHibernate/MappingModel/ParentMapping.cs
index 0595361d4..d7ad71e87 100644
--- a/src/FluentNHibernate/MappingModel/ParentMapping.cs
+++ b/src/FluentNHibernate/MappingModel/ParentMapping.cs
@@ -52,8 +52,8 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((attributes != null ? attributes.GetHashCode() : 0) * 397) ^
-                   (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+            return ((attributes is not null ? attributes.GetHashCode() : 0) * 397) ^
+                   (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/PropertyMapping.cs b/src/FluentNHibernate/MappingModel/PropertyMapping.cs
index 2a05d002a..503fa2590 100644
--- a/src/FluentNHibernate/MappingModel/PropertyMapping.cs
+++ b/src/FluentNHibernate/MappingModel/PropertyMapping.cs
@@ -94,7 +94,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0) * 397) ^ (Member != null ? Member.GetHashCode() : 0);
+            return ((ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0) * 397) ^ (Member is not null ? Member.GetHashCode() : 0);
         }
     }
 
diff --git a/src/FluentNHibernate/MappingModel/StoredProcedureMapping.cs b/src/FluentNHibernate/MappingModel/StoredProcedureMapping.cs
index 4b17816e5..3bdd23d28 100644
--- a/src/FluentNHibernate/MappingModel/StoredProcedureMapping.cs
+++ b/src/FluentNHibernate/MappingModel/StoredProcedureMapping.cs
@@ -86,7 +86,7 @@ public override int GetHashCode()
         unchecked
         {
             {
-                return (base.GetHashCode() * 397) ^ (attributes != null ? attributes.GetHashCode() : 0);
+                return (base.GetHashCode() * 397) ^ (attributes is not null ? attributes.GetHashCode() : 0);
             }
         }
     }
diff --git a/src/FluentNHibernate/MappingModel/TuplizerMapping.cs b/src/FluentNHibernate/MappingModel/TuplizerMapping.cs
index e764bb184..4be63a8f2 100644
--- a/src/FluentNHibernate/MappingModel/TuplizerMapping.cs
+++ b/src/FluentNHibernate/MappingModel/TuplizerMapping.cs
@@ -61,7 +61,7 @@ public override bool Equals(object obj)
 
     public override int GetHashCode()
     {
-        return (attributes != null ? attributes.GetHashCode() : 0);
+        return (attributes is not null ? attributes.GetHashCode() : 0);
     }
 
     public void Set<T>(Expression<Func<TuplizerMapping, T>> expression, int layer, T value)
diff --git a/src/FluentNHibernate/MappingModel/TypeReference.cs b/src/FluentNHibernate/MappingModel/TypeReference.cs
index 141e9b020..06a2f0e49 100644
--- a/src/FluentNHibernate/MappingModel/TypeReference.cs
+++ b/src/FluentNHibernate/MappingModel/TypeReference.cs
@@ -34,7 +34,7 @@ public bool IsEnum
     {
         get
         {
-            if (innerType == null)
+            if (innerType is null)
                 return false;
 
             if (innerType.IsGenericType)
@@ -60,7 +60,7 @@ public bool IsGenericType
     {
         get
         {
-            if (innerType == null)
+            if (innerType is null)
                 return false;
 
             return innerType.IsGenericType;
@@ -71,7 +71,7 @@ public bool IsGenericTypeDefinition
     {
         get
         {
-            if (innerType == null)
+            if (innerType is null)
                 return false;
 
             return innerType.IsGenericTypeDefinition;
@@ -80,7 +80,7 @@ public bool IsGenericTypeDefinition
 
     public Type GetGenericTypeDefinition()
     {
-        if (innerType == null)
+        if (innerType is null)
             return null;
 
         return innerType.GetGenericTypeDefinition();
@@ -98,7 +98,7 @@ public bool IsNullable
 
     public Type[] GetGenericArguments()
     {
-        if (innerType == null)
+        if (innerType is null)
             return Array.Empty<Type>();
 
         return innerType.GetGenericArguments();
@@ -111,16 +111,16 @@ public IEnumerable<Type> GenericArguments
 
     public override string ToString()
     {
-        return innerType == null ? innerName : innerType.AssemblyQualifiedName;
+        return innerType is null ? innerName : innerType.AssemblyQualifiedName;
     }
 
     public bool Equals(TypeReference other)
     {
         if(ReferenceEquals(other, null))
             return false;
-        if (other.innerType == null && innerType == null)
+        if (other.innerType is null && innerType is null)
             return other.innerName.Equals(innerName);                        
-        if (other.innerType != null)
+        if (other.innerType is not null)
             return other.innerType.Equals(innerType);
 
         return false;
@@ -142,7 +142,7 @@ public bool Equals(string other)
 
     public override bool Equals(object obj)
     {
-        if(obj == null)
+        if(obj is null)
             return false;
         if (obj.GetType() == typeof(TypeReference))
             return Equals((TypeReference)obj);
@@ -158,7 +158,7 @@ public override int GetHashCode()
     {
         unchecked
         {
-            return ((innerType != null ? innerType.GetHashCode() : 0) * 397) ^ (innerName != null ? innerName.GetHashCode() : 0);
+            return ((innerType is not null ? innerType.GetHashCode() : 0) * 397) ^ (innerName is not null ? innerName.GetHashCode() : 0);
         }
     }
 
@@ -169,9 +169,9 @@ public Type GetUnderlyingSystemType()
 
     public static bool operator ==(TypeReference original, Type type)
     {
-        if (type == null)
+        if (type is null)
             return false;
-        if (original == (Type)null || original.innerType == null)
+        if (original == (Type)null || original.innerType is null)
             return false;
 
         return original.innerType == type;
diff --git a/src/FluentNHibernate/MappingModel/VersionMapping.cs b/src/FluentNHibernate/MappingModel/VersionMapping.cs
index e9f2a52df..8ecd3ba3b 100644
--- a/src/FluentNHibernate/MappingModel/VersionMapping.cs
+++ b/src/FluentNHibernate/MappingModel/VersionMapping.cs
@@ -69,7 +69,7 @@ public override int GetHashCode()
         unchecked
         {
             {
-                return (base.GetHashCode() * 397) ^ (ContainingEntityType != null ? ContainingEntityType.GetHashCode() : 0);
+                return (base.GetHashCode() * 397) ^ (ContainingEntityType is not null ? ContainingEntityType.GetHashCode() : 0);
             }
         }
     }
diff --git a/src/FluentNHibernate/PersistenceModel.cs b/src/FluentNHibernate/PersistenceModel.cs
index 2618fcad4..b24cbd318 100644
--- a/src/FluentNHibernate/PersistenceModel.cs
+++ b/src/FluentNHibernate/PersistenceModel.cs
@@ -215,7 +215,7 @@ private void ApplyVisitors(IEnumerable<HibernateMapping> mappings)
 
     private void EnsureMappingsBuilt()
     {
-        if (compiledMappings != null) return;
+        if (compiledMappings is not null) return;
 
         compiledMappings = BuildMappings();
     }
@@ -265,7 +265,7 @@ private void WriteMappingsTo(Func<HibernateMapping, XmlTextWriter> writerBuilder
             }
             finally
             {
-                if(shouldDispose && xmlWriter != null)
+                if(shouldDispose && xmlWriter is not null)
                     xmlWriter.Close();
             }
         }
@@ -287,7 +287,7 @@ public virtual void Configure(Configuration cfg)
             var serializer = new MappingXmlSerializer();
             XmlDocument document = serializer.Serialize(mapping);
 
-            if (cfg.GetClassMapping(mapping.Classes.First().Type) == null)
+            if (cfg.GetClassMapping(mapping.Classes.First().Type) is null)
                 cfg.AddDocument(document);
         }
     }
diff --git a/src/FluentNHibernate/Reveal.cs b/src/FluentNHibernate/Reveal.cs
index e962c8214..8e18c6265 100644
--- a/src/FluentNHibernate/Reveal.cs
+++ b/src/FluentNHibernate/Reveal.cs
@@ -47,7 +47,7 @@ static Expression<Func<TEntity, TReturn>> CreateExpression<TEntity, TReturn>(str
         var member = type.GetInstanceMembers()
             .FirstOrDefault(x => x.Name == propertyName);
 
-        if (member == null)
+        if (member is null)
             throw new UnknownPropertyException(type, propertyName);
 
         var param = Expression.Parameter(member.DeclaringType, "x");
diff --git a/src/FluentNHibernate/SessionSource.cs b/src/FluentNHibernate/SessionSource.cs
index fd1c03146..4ceb1aa86 100644
--- a/src/FluentNHibernate/SessionSource.cs
+++ b/src/FluentNHibernate/SessionSource.cs
@@ -43,7 +43,7 @@ public SessionSource(FluentConfiguration config)
 
     protected void Initialize(Configuration nhibernateConfig, PersistenceModel model)
     {
-        if( model == null ) throw new ArgumentNullException("model", "Model cannot be null");
+        if( model is null ) throw new ArgumentNullException("model", "Model cannot be null");
 
         Configuration = nhibernateConfig;
 
diff --git a/src/FluentNHibernate/Testing/PersistenceSpecification.cs b/src/FluentNHibernate/Testing/PersistenceSpecification.cs
index 55906d093..6ba4c5efa 100644
--- a/src/FluentNHibernate/Testing/PersistenceSpecification.cs
+++ b/src/FluentNHibernate/Testing/PersistenceSpecification.cs
@@ -32,7 +32,7 @@ public PersistenceSpecification(ISession session, IEqualityComparer entityEquali
     {
         currentSession = session;
 #pragma warning disable CS0618 // ISession.Transaction is obsolete
-        hasExistingTransaction = currentSession.Transaction != null && currentSession.Transaction.IsActive || System.Transactions.Transaction.Current != null;
+        hasExistingTransaction = currentSession.Transaction is not null && currentSession.Transaction.IsActive || System.Transactions.Transaction.Current is not null;
 #pragma warning restore CS0618
         this.entityEqualityComparer = entityEqualityComparer;
     }
diff --git a/src/FluentNHibernate/Testing/PersistenceSpecificationExtensions.cs b/src/FluentNHibernate/Testing/PersistenceSpecificationExtensions.cs
index 7b541cf09..215083e09 100644
--- a/src/FluentNHibernate/Testing/PersistenceSpecificationExtensions.cs
+++ b/src/FluentNHibernate/Testing/PersistenceSpecificationExtensions.cs
@@ -89,7 +89,7 @@ public static PersistenceSpecification<T> CheckReference<T, TReference>(this Per
     {
         // Because of the params keyword, the compiler will select this overload
         // instead of the one above, even when no funcs are supplied in the method call.
-        if (propertiesToCompare == null || propertiesToCompare.Length == 0)
+        if (propertiesToCompare is null || propertiesToCompare.Length == 0)
             return spec.CheckReference(expression, propertyValue, (IEqualityComparer)null);
 
         return spec.CheckReference(expression, propertyValue, new FuncEqualityComparer<TReference>(propertiesToCompare));
@@ -142,7 +142,7 @@ public static PersistenceSpecification<T> CheckList<T, TListElement>(this Persis
     {
         // Because of the params keyword, the compiler can select this overload
         // instead of the one above, even when no funcs are supplied in the method call.
-        if (propertiesToCompare == null || propertiesToCompare.Length == 0)
+        if (propertiesToCompare is null || propertiesToCompare.Length == 0)
             return spec.CheckList(expression, propertyValue, (IEqualityComparer)null);
 
         return spec.CheckList(expression, propertyValue, new FuncEqualityComparer<TListElement>(propertiesToCompare));
@@ -165,7 +165,7 @@ public static PersistenceSpecification<T> CheckInverseList<T, TListElement>(this
     {
         // Because of the params keyword, the compiler can select this overload
         // instead of the one above, even when no funcs are supplied in the method call.
-        if (propertiesToCompare == null || propertiesToCompare.Length == 0)
+        if (propertiesToCompare is null || propertiesToCompare.Length == 0)
             return spec.CheckList(expression, propertyValue, (IEqualityComparer)null);
 
         return spec.CheckInverseList(expression, propertyValue, new FuncEqualityComparer<TListElement>(propertiesToCompare));
@@ -275,7 +275,7 @@ public static PersistenceSpecification<T> CheckInverseBag<T, TListElement>(this
     {
         // Because of the params keyword, the compiler can select this overload
         // instead of the one above, even when no funcs are supplied in the method call.
-        if (propertiesToCompare == null || propertiesToCompare.Length == 0)
+        if (propertiesToCompare is null || propertiesToCompare.Length == 0)
             return spec.CheckInverseBag(expression, propertyValue, (IEqualityComparer)null);
 
         return spec.CheckInverseBag(expression, propertyValue, new FuncEqualityComparer<TListElement>(propertiesToCompare));
@@ -355,7 +355,7 @@ public static PersistenceSpecification<T> CheckBag<T, TListElement>(this Persist
     {
         // Because of the params keyword, the compiler can select this overload
         // instead of the one above, even when no funcs are supplied in the method call.
-        if (propertiesToCompare == null || propertiesToCompare.Length == 0)
+        if (propertiesToCompare is null || propertiesToCompare.Length == 0)
             return spec.CheckBag(expression, propertyValue, (IEqualityComparer)null);
 
         return spec.CheckBag(expression, propertyValue, new FuncEqualityComparer<TListElement>(propertiesToCompare));
diff --git a/src/FluentNHibernate/Testing/SingleConnectionSessionSourceForSQLiteInMemoryTesting.cs b/src/FluentNHibernate/Testing/SingleConnectionSessionSourceForSQLiteInMemoryTesting.cs
index b0dcc769a..aa3c878f1 100644
--- a/src/FluentNHibernate/Testing/SingleConnectionSessionSourceForSQLiteInMemoryTesting.cs
+++ b/src/FluentNHibernate/Testing/SingleConnectionSessionSourceForSQLiteInMemoryTesting.cs
@@ -18,7 +18,7 @@ public SingleConnectionSessionSourceForSQLiteInMemoryTesting(FluentConfiguration
 
     protected void EnsureCurrentSession()
     {
-        if (session == null)
+        if (session is null)
             session = base.CreateSession();
     }
 
diff --git a/src/FluentNHibernate/Testing/Values/List.cs b/src/FluentNHibernate/Testing/Values/List.cs
index 1f734bb3a..f4d699504 100644
--- a/src/FluentNHibernate/Testing/Values/List.cs
+++ b/src/FluentNHibernate/Testing/Values/List.cs
@@ -21,7 +21,7 @@ public override Action<T, Accessor, IEnumerable<TListElement>> ValueSetter
     {
         get
         {
-            if (_valueSetter != null)
+            if (_valueSetter is not null)
             {
                 return _valueSetter;
             }
@@ -67,12 +67,12 @@ public override void CheckValue(object target)
 
     private void AssertGenericListMatches(IEnumerable actualEnumerable, IEnumerable<TListElement> expectedEnumerable)
     {
-        if (actualEnumerable == null)
+        if (actualEnumerable is null)
         {
             throw new ArgumentNullException("actualEnumerable",
                 "Actual and expected are not equal (actual was null).");
         }
-        if (expectedEnumerable == null)
+        if (expectedEnumerable is null)
         {
             throw new ArgumentNullException("expectedEnumerable",
                 "Actual and expected are not equal (expected was null).");
@@ -91,7 +91,7 @@ private void AssertGenericListMatches(IEnumerable actualEnumerable, IEnumerable<
             throw new ApplicationException(String.Format("Actual count ({0}) does not equal expected count ({1})", actualList.Count, expectedList.Count));
         }
 
-        var equalsFunc = (EntityEqualityComparer != null) ? ((a, b) => EntityEqualityComparer.Equals(a, b)): new Func<object, object, bool>(Equals);
+        var equalsFunc = (EntityEqualityComparer is not null) ? ((a, b) => EntityEqualityComparer.Equals(a, b)): new Func<object, object, bool>(Equals);
 
         for (var i = 0; i < actualList.Count; i++)
         {
diff --git a/src/FluentNHibernate/Testing/Values/Property.cs b/src/FluentNHibernate/Testing/Values/Property.cs
index 215b8de1b..e5773410a 100644
--- a/src/FluentNHibernate/Testing/Values/Property.cs
+++ b/src/FluentNHibernate/Testing/Values/Property.cs
@@ -31,7 +31,7 @@ public virtual Action<T, Accessor, TProperty> ValueSetter
     {
         get
         {
-            if (_valueSetter != null)
+            if (_valueSetter is not null)
             {
                 return _valueSetter;
             }
@@ -70,10 +70,10 @@ public override void CheckValue(object target)
 
         bool areEqual;
             
-        if (EntityEqualityComparer != null)
+        if (EntityEqualityComparer is not null)
             areEqual = EntityEqualityComparer.Equals(Value, actual);
-        else if (Value == null)
-            areEqual = actual == null;
+        else if (Value is null)
+            areEqual = actual is null;
         else
             areEqual = Value.Equals(actual);
 
@@ -87,11 +87,11 @@ private string GetInequalityComparisonMessage(object actual)
     {
         string message;
 
-        string actualToPrint = actual != null ? actual.ToString() : "(null)";
+        string actualToPrint = actual is not null ? actual.ToString() : "(null)";
         string actualTypeToPrint = PropertyAccessor.PropertyType.FullName;
 
-        string valueToPrint = Value != null ? Value.ToString() : "(null)";
-        string valueTypeToPrint = Value != null ? Value.GetType().FullName : "(null)";
+        string valueToPrint = Value is not null ? Value.ToString() : "(null)";
+        string valueTypeToPrint = Value is not null ? Value.GetType().FullName : "(null)";
 
         if (actualToPrint != valueToPrint && actualTypeToPrint != valueTypeToPrint)
         {
diff --git a/src/FluentNHibernate/Testing/Values/ReferenceBag.cs b/src/FluentNHibernate/Testing/Values/ReferenceBag.cs
index caf9debb3..47fef6275 100644
--- a/src/FluentNHibernate/Testing/Values/ReferenceBag.cs
+++ b/src/FluentNHibernate/Testing/Values/ReferenceBag.cs
@@ -19,12 +19,12 @@ public override void CheckValue(object target)
 
     private void AssertGenericListMatches(IEnumerable actualEnumerable, IEnumerable<TListElement> expectedEnumerable)
     {
-        if (actualEnumerable == null)
+        if (actualEnumerable is null)
         {
             throw new ArgumentNullException("actualEnumerable",
                 "Actual and expected are not equal (actual was null).");
         }
-        if (expectedEnumerable == null)
+        if (expectedEnumerable is null)
         {
             throw new ArgumentNullException("expectedEnumerable",
                 "Actual and expected are not equal (expected was null).");
@@ -39,13 +39,13 @@ private void AssertGenericListMatches(IEnumerable actualEnumerable, IEnumerable<
             throw new ApplicationException(String.Format("Actual count ({0}) does not equal expected count ({1})", actualList.Count, expectedList.Count));
         }
 
-        var equalsFunc = (EntityEqualityComparer != null)
+        var equalsFunc = (EntityEqualityComparer is not null)
             ? new Func<object, object, bool>((a, b) => EntityEqualityComparer.Equals(a, b))
             : new Func<object, object, bool>(Equals);
 
 
         var result = actualList.FirstOrDefault(item => actualList.Count(x => equalsFunc(item, x)) != expectedList.Count(x => equalsFunc(item, x)));
-        if (result != null)
+        if (result is not null)
         {
             throw new ApplicationException(String.Format("Actual count of item {0} ({1}) does not equal expected item count ({2})",result, actualList.Count(x => x == result), expectedList.Count(x => (object)x == result)));
         }
diff --git a/src/FluentNHibernate/Utils/Extensions.cs b/src/FluentNHibernate/Utils/Extensions.cs
index 8b82f4ef1..8788423d6 100644
--- a/src/FluentNHibernate/Utils/Extensions.cs
+++ b/src/FluentNHibernate/Utils/Extensions.cs
@@ -55,7 +55,7 @@ public static object InstantiateUsingParameterlessConstructor(this Type type)
     {
         var constructor = ReflectHelper.GetDefaultConstructor(type);
 
-        if (constructor == null)
+        if (constructor is null)
             throw new MissingConstructorException(type);
 
         return constructor.Invoke(null);
diff --git a/src/FluentNHibernate/Utils/ObservableDictionary.cs b/src/FluentNHibernate/Utils/ObservableDictionary.cs
index 18cdb7534..4110408ca 100644
--- a/src/FluentNHibernate/Utils/ObservableDictionary.cs
+++ b/src/FluentNHibernate/Utils/ObservableDictionary.cs
@@ -58,7 +58,7 @@ public bool ContainsKey(TKey key) {
     public ICollection<TKey> Keys => Dictionary.Keys;
 
     public bool Remove(TKey key) {
-        if (key == null) throw new ArgumentNullException("key");
+        if (key is null) throw new ArgumentNullException("key");
 
         TValue value;
         Dictionary.TryGetValue(key, out value);
@@ -142,7 +142,7 @@ IEnumerator IEnumerable.GetEnumerator() {
     #endregion
 
     public void AddRange(IDictionary<TKey, TValue> items) {
-        if (items == null) throw new ArgumentNullException("items");
+        if (items is null) throw new ArgumentNullException("items");
 
         if (items.Count > 0) {
             if (Dictionary.Count > 0) {
@@ -158,7 +158,7 @@ public void AddRange(IDictionary<TKey, TValue> items) {
     }
 
     private void Insert(TKey key, TValue value, bool add) {
-        if (key == null) throw new ArgumentNullException("key");
+        if (key is null) throw new ArgumentNullException("key");
 
         TValue item;
         if (Dictionary.TryGetValue(key, out item)) {
diff --git a/src/FluentNHibernate/Utils/Reflection/PropertyChain.cs b/src/FluentNHibernate/Utils/Reflection/PropertyChain.cs
index 48398ee92..48406cd19 100644
--- a/src/FluentNHibernate/Utils/Reflection/PropertyChain.cs
+++ b/src/FluentNHibernate/Utils/Reflection/PropertyChain.cs
@@ -25,7 +25,7 @@ public PropertyChain(Member[] members)
     public void SetValue(object target, object propertyValue)
     {
         target = findInnerMostTarget(target);
-        if (target == null)
+        if (target is null)
         {
             return;
         }
@@ -37,7 +37,7 @@ public object GetValue(object target)
     {
         target = findInnerMostTarget(target);
 
-        if (target == null)
+        if (target is null)
         {
             return null;
         }
@@ -93,7 +93,7 @@ private object findInnerMostTarget(object target)
         foreach (var info in _chain)
         {
             target = info.GetValue(target);
-            if (target == null)
+            if (target is null)
             {
                 return null;
             }
diff --git a/src/FluentNHibernate/Utils/Reflection/ReflectionHelper.cs b/src/FluentNHibernate/Utils/Reflection/ReflectionHelper.cs
index 37edf749b..e54fde8bb 100644
--- a/src/FluentNHibernate/Utils/Reflection/ReflectionHelper.cs
+++ b/src/FluentNHibernate/Utils/Reflection/ReflectionHelper.cs
@@ -65,7 +65,7 @@ private static PropertyInfo GetDynamicComponentProperty(Expression expression)
         MethodCallExpression methodCallExpression = null;
         var nextOperand = expression;
 
-        while (nextOperand != null)
+        while (nextOperand is not null)
         {
             if (nextOperand.NodeType == ExpressionType.Call)
             {
@@ -105,7 +105,7 @@ private static MemberExpression GetMemberExpression(Expression expression, bool
             memberExpression = expression as MemberExpression;
         }
 
-        if (enforceCheck && memberExpression == null)
+        if (enforceCheck && memberExpression is null)
         {
             throw new ArgumentException("Not a member access", "expression");
         }
@@ -117,7 +117,7 @@ private static Accessor getAccessor(MemberExpression memberExpression)
     {
         var list = new List<Member>();
 
-        while (memberExpression != null)
+        while (memberExpression is not null)
         {
             list.Add(memberExpression.Member.ToMember());
             memberExpression = memberExpression.Expression as MemberExpression;
diff --git a/src/FluentNHibernate/Utils/StringLikeness.cs b/src/FluentNHibernate/Utils/StringLikeness.cs
index 3f60faba9..1553ff667 100644
--- a/src/FluentNHibernate/Utils/StringLikeness.cs
+++ b/src/FluentNHibernate/Utils/StringLikeness.cs
@@ -12,8 +12,8 @@ public static class StringLikeness
     public static int EditDistance(string x, string y)
     {
         // Validate parameters
-        if (x == null) throw new ArgumentNullException("x");
-        if (y == null) throw new ArgumentNullException("y");
+        if (x is null) throw new ArgumentNullException("x");
+        if (y is null) throw new ArgumentNullException("y");
 
         // Convert the parameters into IList instances
         // in order to obtain indexing capabilities
diff --git a/src/FluentNHibernate/Utils/XmlExtensions.cs b/src/FluentNHibernate/Utils/XmlExtensions.cs
index 791e56c86..30f8ecef4 100644
--- a/src/FluentNHibernate/Utils/XmlExtensions.cs
+++ b/src/FluentNHibernate/Utils/XmlExtensions.cs
@@ -47,7 +47,7 @@ public static XmlElement WithAtt(this XmlElement element, string key, string att
     public static void SetAttributeOnChild(this XmlElement element, string childName, string attName, string attValue)
     {
         XmlElement childElement = element[childName];
-        if (childElement == null)
+        if (childElement is null)
         {
             childElement = element.AddElement(childName);
         }
diff --git a/src/FluentNHibernate/Visitors/ComponentReferenceResolutionVisitor.cs b/src/FluentNHibernate/Visitors/ComponentReferenceResolutionVisitor.cs
index 80fc51337..8daecf491 100644
--- a/src/FluentNHibernate/Visitors/ComponentReferenceResolutionVisitor.cs
+++ b/src/FluentNHibernate/Visitors/ComponentReferenceResolutionVisitor.cs
@@ -29,7 +29,7 @@ public ExternalComponentMapping Resolve(ComponentResolutionContext context, IEnu
 
         var provider = providers.SingleOrDefault();
 
-        if (provider == null)
+        if (provider is null)
             return null;
 
         return provider.GetComponentMapping();
@@ -57,9 +57,9 @@ public override void ProcessComponent(ReferenceComponentMapping mapping)
         };
         var component = resolvers
             .Select(x => x.Resolve(context, componentProviders))
-            .FirstOrDefault(x => x != null);
+            .FirstOrDefault(x => x is not null);
 
-        if (component == null)
+        if (component is null)
             throw new MissingExternalComponentException(mapping.Type, mapping.ContainingEntityType, mapping.Member);
 
         mapping.AssociateExternalMapping(component);
diff --git a/src/FluentNHibernate/Visitors/ConventionVisitor.cs b/src/FluentNHibernate/Visitors/ConventionVisitor.cs
index 1d8f8719f..86502149c 100644
--- a/src/FluentNHibernate/Visitors/ConventionVisitor.cs
+++ b/src/FluentNHibernate/Visitors/ConventionVisitor.cs
@@ -266,7 +266,7 @@ static void Apply<TInspector, TInstance>(IEnumerable conventions, TInstance inst
             var criteria = new ConcreteAcceptanceCriteria<TInspector>();
             var acceptance = convention as IConventionAcceptance<TInspector>;
 
-            if (acceptance != null)
+            if (acceptance is not null)
                 acceptance.Accept(criteria);
 
             if (criteria.Matches(instance))
diff --git a/src/FluentNHibernate/Visitors/ManyToManyTableNameVisitor.cs b/src/FluentNHibernate/Visitors/ManyToManyTableNameVisitor.cs
index 6ea035d29..a7aeb3f9c 100644
--- a/src/FluentNHibernate/Visitors/ManyToManyTableNameVisitor.cs
+++ b/src/FluentNHibernate/Visitors/ManyToManyTableNameVisitor.cs
@@ -10,7 +10,7 @@ public override void ProcessCollection(CollectionMapping mapping)
         if (!(mapping.Relationship is ManyToManyMapping))
             return;
 
-        if (mapping.OtherSide == null)
+        if (mapping.OtherSide is null)
         {
             // uni-directional
             mapping.Set(x => x.TableName, Layer.Defaults, mapping.ChildType.Name + "To" + mapping.ContainingEntityType.Name);
diff --git a/src/FluentNHibernate/Visitors/RelationshipKeyPairingVisitor.cs b/src/FluentNHibernate/Visitors/RelationshipKeyPairingVisitor.cs
index 56f7f13b7..330be606a 100644
--- a/src/FluentNHibernate/Visitors/RelationshipKeyPairingVisitor.cs
+++ b/src/FluentNHibernate/Visitors/RelationshipKeyPairingVisitor.cs
@@ -8,7 +8,7 @@ public class RelationshipKeyPairingVisitor : DefaultMappingModelVisitor
 {
     public override void ProcessManyToOne(ManyToOneMapping thisSide)
     {
-        if (thisSide.OtherSide == null)
+        if (thisSide.OtherSide is null)
             return;
 
         // other side is always going to be a collection for a many-to-one mapping
diff --git a/src/FluentNHibernate/Visitors/RelationshipPairingVisitor.cs b/src/FluentNHibernate/Visitors/RelationshipPairingVisitor.cs
index 4bd504b20..92b3bd891 100644
--- a/src/FluentNHibernate/Visitors/RelationshipPairingVisitor.cs
+++ b/src/FluentNHibernate/Visitors/RelationshipPairingVisitor.cs
@@ -52,11 +52,11 @@ static void PairOneToManys(IEnumerable<CollectionMapping> collections, IEnumerab
             var childType = collection.ChildType;
             var reference = orderedRefs
                 .FirstOrDefault(x => 
-                    x.OtherSide == null && 
+                    x.OtherSide is null && 
                     x.Class.GetUnderlyingSystemType() == type &&
                     x.ContainingEntityType == childType);
 
-            if (reference == null) continue;
+            if (reference is null) continue;
 
             collection.OtherSide = reference;
             reference.OtherSide = collection;
@@ -83,7 +83,7 @@ void PairManyToManys(IEnumerable<CollectionMapping> rs)
         else if (candidatesCount > 1)
             mapping = PairFuzzyMatches(rs, current, candidates);
 
-        if (mapping == null)
+        if (mapping is null)
         {
             // couldn't pair at all, going to defer to the user for this one
             // and if they can't do anything we'll just treat it as uni-directional
@@ -148,7 +148,7 @@ static CollectionMapping PairFuzzyMatches(IEnumerable<CollectionMapping> rs, Col
 
         var first = likenesses.FirstOrDefault();
 
-        if (first == null || AnyHaveSameLikeness(likenesses, first))
+        if (first is null || AnyHaveSameLikeness(likenesses, first))
         {
             // couldn't find a definitive match, return nothing and we'll handle
             // this further up
@@ -193,7 +193,7 @@ static CollectionMapping FindAlternative(IEnumerable<CollectionMapping> rs, Coll
             .OrderBy(x => x.Differences)
             .FirstOrDefault();
 
-        if (alternative == null)
+        if (alternative is null)
             return null;
 
         return alternative.Collection;
@@ -228,8 +228,8 @@ public override int GetHashCode()
         {
             unchecked
             {
-                int result = (CurrentMemberName != null ? CurrentMemberName.GetHashCode() : 0);
-                result = (result * 397) ^ (MappingMemberName != null ? MappingMemberName.GetHashCode() : 0);
+                int result = (CurrentMemberName is not null ? CurrentMemberName.GetHashCode() : 0);
+                result = (result * 397) ^ (MappingMemberName is not null ? MappingMemberName.GetHashCode() : 0);
                 return result;
             }
         }
diff --git a/src/FluentNHibernate/Visitors/SeparateSubclassVisitor.cs b/src/FluentNHibernate/Visitors/SeparateSubclassVisitor.cs
index 13f6d7080..f54e069c4 100644
--- a/src/FluentNHibernate/Visitors/SeparateSubclassVisitor.cs
+++ b/src/FluentNHibernate/Visitors/SeparateSubclassVisitor.cs
@@ -59,7 +59,7 @@ private SubclassType GetSubclassType(ClassMapping mapping)
             return SubclassType.UnionSubclass;
         }
 
-        if (mapping.Discriminator == null)
+        if (mapping.Discriminator is null)
             return SubclassType.JoinedSubclass;
 
         return SubclassType.Subclass;
diff --git a/src/FluentNHibernate/Visitors/ValidationVisitor.cs b/src/FluentNHibernate/Visitors/ValidationVisitor.cs
index d7fad221d..a2fd21936 100644
--- a/src/FluentNHibernate/Visitors/ValidationVisitor.cs
+++ b/src/FluentNHibernate/Visitors/ValidationVisitor.cs
@@ -16,7 +16,7 @@ public ValidationVisitor()
     public override void ProcessClass(ClassMapping classMapping)
     {
         if (!Enabled) return;
-        if (classMapping.Id == null)
+        if (classMapping.Id is null)
             throw new ValidationException(
                 string.Format("The entity '{0}' doesn't have an Id mapped.", classMapping.Type.Name),
                 "Use the Id method to map your identity property. For example: Id(x => x.Id)",
@@ -30,7 +30,7 @@ public override void ProcessCollection(CollectionMapping mapping)
 
         var otherSide = mapping.OtherSide as CollectionMapping;
 
-        if (otherSide == null) return;
+        if (otherSide is null) return;
         if (mapping.Inverse && otherSide.Inverse)
         {
             throw new ValidationException(