diff --git a/Generator/Sources/ProjectionModel/CAbi/CAbi+writing.swift b/Generator/Sources/ProjectionModel/CAbi/CAbi+writing.swift
index 2faaa5a..726ac51 100644
--- a/Generator/Sources/ProjectionModel/CAbi/CAbi+writing.swift
+++ b/Generator/Sources/ProjectionModel/CAbi/CAbi+writing.swift
@@ -20,8 +20,9 @@ extension CAbi {
     }
 
     public static func writeEnumTypedef(_ enumDefinition: EnumDefinition, to writer: CSourceFileWriter) throws {
-        let mangledName = try CAbi.mangleName(type: enumDefinition.bindType())
-        writer.writeTypedef(type: .reference(name: "int32_t"), name: mangledName)
+        try writer.writeTypedef(
+            type: .reference(name: enumDefinition.isFlags ? "uint32_t" : "int32_t"),
+            name: CAbi.mangleName(type: enumDefinition.bindType()))
     }
 
     public static func writeStruct(_ structDefinition: StructDefinition, to writer: CSourceFileWriter) throws {
diff --git a/InteropTests/Tests/EnumTests.swift b/InteropTests/Tests/EnumTests.swift
index 2cb0b66..36c2efe 100644
--- a/InteropTests/Tests/EnumTests.swift
+++ b/InteropTests/Tests/EnumTests.swift
@@ -16,4 +16,12 @@ class EnumTests: WinRTTestCase {
         XCTAssertEqual(Flags.bit16.rawValue, 0x10000)
         XCTAssertEqual(Flags.all.rawValue, 0xFFFFFFFF)
     }
+
+    func testFlagsSetAlgebra() throws {
+        XCTAssert(try Enums.hasFlags(Flags.bit0.union(Flags.bit16), Flags.bit0))
+        XCTAssert(try Enums.hasFlags(Flags.bit0.union(Flags.bit16), Flags.bit16))
+        XCTAssert(try Enums.hasFlags(Flags.all.intersection(Flags.bit0), Flags.bit0))
+        XCTAssertFalse(try Enums.hasFlags(Flags.all.intersection(Flags.bit0), Flags.bit16))
+        XCTAssertFalse(try Enums.hasFlags(Flags.bit0, Flags.bit16))
+    }
 }
\ No newline at end of file
diff --git a/InteropTests/WinRTComponent/Dll/Enums.cpp b/InteropTests/WinRTComponent/Dll/Enums.cpp
new file mode 100644
index 0000000..5c6259e
--- /dev/null
+++ b/InteropTests/WinRTComponent/Dll/Enums.cpp
@@ -0,0 +1,11 @@
+#include "pch.h"
+#include "Enums.h"
+#include "Enums.g.cpp"
+
+namespace winrt::WinRTComponent::implementation
+{
+    boolean Enums::HasFlags(Flags value, Flags flags)
+    {
+        return (value & flags) == flags;
+    }
+}
diff --git a/InteropTests/WinRTComponent/Dll/Enums.h b/InteropTests/WinRTComponent/Dll/Enums.h
new file mode 100644
index 0000000..50fc080
--- /dev/null
+++ b/InteropTests/WinRTComponent/Dll/Enums.h
@@ -0,0 +1,18 @@
+#pragma once
+#include "Enums.g.h"
+
+namespace winrt::WinRTComponent::implementation
+{
+    struct Enums
+    {
+        Enums() = default;
+
+        static boolean HasFlags(Flags value, Flags flags);
+    };
+}
+namespace winrt::WinRTComponent::factory_implementation
+{
+    struct Enums : EnumsT<Enums, implementation::Enums>
+    {
+    };
+}
diff --git a/InteropTests/WinRTComponent/IDL/Enums.idl b/InteropTests/WinRTComponent/IDL/Enums.idl
index 6eb9daf..265eb43 100644
--- a/InteropTests/WinRTComponent/IDL/Enums.idl
+++ b/InteropTests/WinRTComponent/IDL/Enums.idl
@@ -15,4 +15,9 @@ namespace WinRTComponent
         Bit16 = 0x10000,
         All = 0xFFFFFFFF,
     };
+
+    static runtimeclass Enums
+    {
+        static Boolean HasFlags(Flags value, Flags flags);
+    };
 }
\ No newline at end of file