diff --git a/src/TypedSignalR.Client.TypeScript/RoslynExtensions.TypeCollector.cs b/src/TypedSignalR.Client.TypeScript/RoslynExtensions.TypeCollector.cs
index 55c009a..f6a57f8 100644
--- a/src/TypedSignalR.Client.TypeScript/RoslynExtensions.TypeCollector.cs
+++ b/src/TypedSignalR.Client.TypeScript/RoslynExtensions.TypeCollector.cs
@@ -68,6 +68,7 @@ public static IReadOnlyList<INamedTypeSymbol> GetAttributeAnnotatedTypes(this Co
 
                 return attributes.Any(a => SymbolEqualityComparer.Default.Equals(a.AttributeClass, attributeSymbol));
             })
+            .Distinct<INamedTypeSymbol>(SymbolEqualityComparer.Default)
             .ToArray();
 
         return types;
@@ -100,6 +101,7 @@ public static IReadOnlyList<INamedTypeSymbol> GetAttributeAnnotatedTypes(
 
                 return false;
             })
+            .Distinct<INamedTypeSymbol>(SymbolEqualityComparer.Default)
             .ToArray();
 
         return types;
diff --git a/tests/TypedSignalR.Client.TypeScript.Tests.Shared/IUnaryHub.cs b/tests/TypedSignalR.Client.TypeScript.Tests.Shared/IUnaryHub.cs
index 87d8d98..bb8baea 100644
--- a/tests/TypedSignalR.Client.TypeScript.Tests.Shared/IUnaryHub.cs
+++ b/tests/TypedSignalR.Client.TypeScript.Tests.Shared/IUnaryHub.cs
@@ -43,11 +43,15 @@ public class MyResponseItem2
 }
 
 [Hub]
-public interface IUnaryHub
+public partial interface IUnaryHub
 {
     Task<string> Get();
     Task<int> Add(int x, int y);
     Task<string> Cat(string x, string y);
+}
+
+public partial interface IUnaryHub
+{
     Task<UserDefinedType> Echo(UserDefinedType instance);
     Task<MyEnum> EchoMyEnum(MyEnum myEnum);
     Task<MyResponseItem[]> RequestArray(MyRequestItem[] array);