Correctly respect interfaces in GetInheritanceChain

src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/TypeExtensions.cs

@@ -45,6 +45,8 @@ public static object GetDefaultValue(this Type type)
 
         public static Type[] GetInheritanceChain(this Type type)
         {
+            if (type.IsInterface) { return type.GetInterfaces(); }
+
             var inheritanceChain = new List<Type>();
 
             var current = type;

test/Swashbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs

@@ -236,6 +236,17 @@ public void GenerateSchema_IncludesInheritedProperties_IfTypeIsAnInterfaceHierar
             Assert.Equal(expectedPropertyNames.OrderBy(n => n), schema.Properties.Keys.OrderBy(k => k));
         }
 
+        [Fact]
+        public void GenerateSchema_KeepMostDerivedType_IfTypeIsAnInterface()
+        {
+            var schemaRepository = new SchemaRepository();
+
+            var referenceSchema = Subject().GenerateSchema(typeof(INewBaseInterface), schemaRepository);
+
+            var schema = schemaRepository.Schemas[referenceSchema.Reference.Id];
+            Assert.Equal("integer", schema.Properties["BaseProperty"].Type);
+        }
+
         [Fact]
         public void GenerateSchema_ExcludesIndexerProperties_IfComplexTypeIsIndexed()
         {

test/Swashbuckle.AspNetCore.TestSupport/Fixtures/BaseInterface.cs

@@ -19,4 +19,9 @@ public interface IMultiSubInterface : ISubInterface1, ISubInterface2
     {
         public int Property3 { get; set; }
     }
+
+    public interface INewBaseInterface : IBaseInterface
+    {
+        public new int BaseProperty { get; set; }
+    }
 }