Fixed flags enum signedness mismatch in bindings code

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 {

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))
+    }
 }

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;
+    }
+}

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>
+    {
+    };
+}

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);
+    };
 }