diff --git a/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.VisitDecl.cs b/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.VisitDecl.cs
index c538e421..23e40097 100644
--- a/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.VisitDecl.cs
+++ b/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.VisitDecl.cs
@@ -969,12 +969,7 @@ private void VisitIndirectFieldDecl(IndirectFieldDecl indirectFieldDecl)
 
         var isFixedSizedBuffer = IsTypeConstantOrIncompleteArray(indirectFieldDecl, type);
         var generateCompatibleCode = _config.GenerateCompatibleCode;
-        var typeString = string.Empty;
-
-        if (!fieldDecl.IsBitField && (!isFixedSizedBuffer || generateCompatibleCode))
-        {
-            typeString = "ref ";
-        }
+        var typeStringBuilder = new StringBuilder();
 
         if (IsType<RecordType>(indirectFieldDecl, type, out var recordType))
         {
@@ -985,12 +980,17 @@ private void VisitIndirectFieldDecl(IndirectFieldDecl indirectFieldDecl)
                 var parentRecordDeclName = GetRemappedCursorName(parentRecordDecl);
                 var escapedParentRecordDeclName = EscapeName(parentRecordDeclName);
 
-                typeString += escapedParentRecordDeclName + '.';
+                _ = typeStringBuilder.Insert(0, '.').Insert(0, escapedParentRecordDeclName);
 
                 recordDecl = parentRecordDecl;
             }
         }
 
+        if (!fieldDecl.IsBitField && (!isFixedSizedBuffer || generateCompatibleCode))
+        {
+            _ = typeStringBuilder.Insert(0, "ref ");
+        }
+
         var isSupportedFixedSizedBufferType = isFixedSizedBuffer && IsSupportedFixedSizedBufferType(typeName);
 
         if (isFixedSizedBuffer)
@@ -998,21 +998,22 @@ private void VisitIndirectFieldDecl(IndirectFieldDecl indirectFieldDecl)
             if (!generateCompatibleCode)
             {
                 _outputBuilder.EmitSystemSupport();
-                typeString += "Span<";
+                _ = typeStringBuilder.Append("Span<");
             }
             else if (!isSupportedFixedSizedBufferType)
             {
-                typeString += contextType + '.';
+                _ = typeStringBuilder.Append(contextType).Append('.');
                 typeName = GetArtificialFixedSizedBufferName(fieldDecl);
             }
         }
 
-        typeString += typeName;
+        _ = typeStringBuilder.Append(typeName);
         if (isFixedSizedBuffer && !generateCompatibleCode)
         {
-            typeString += '>';
+            _ = typeStringBuilder.Append('>');
         }
 
+        var typeString = typeStringBuilder.ToString();
         _outputBuilder.WriteRegularField(typeString, escapedName);
 
         var isIndirectPointerField = IsTypePointerOrReference(indirectFieldDecl, type) && !typeName.Equals("IntPtr", StringComparison.Ordinal) && !typeName.Equals("UIntPtr", StringComparison.Ordinal);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/Base/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/Base/UnionDeclarationTest.cs
index 3f64c858..f6ff2143 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/Base/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/Base/UnionDeclarationTest.cs
@@ -182,6 +182,9 @@ public abstract class UnionDeclarationTest : PInvokeGeneratorTest
     [TestCase("bool", "byte")]
     public Task TypedefTest(string nativeType, string expectedManagedType) => TypedefTestImpl(nativeType, expectedManagedType);
 
+    [Test]
+    public Task UnionWithAnonStructWithAnonUnion() => UnionWithAnonStructWithAnonUnionImpl();
+
     protected abstract Task BasicTestImpl(string nativeType, string expectedManagedType);
 
     protected abstract Task BasicTestInCModeImpl(string nativeType, string expectedManagedType);
@@ -237,4 +240,6 @@ public abstract class UnionDeclarationTest : PInvokeGeneratorTest
     protected abstract Task SkipNonDefinitionWithNativeTypeNameTestImpl(string nativeType, string expectedManagedType);
 
     protected abstract Task TypedefTestImpl(string nativeType, string expectedManagedType);
+
+    protected abstract Task UnionWithAnonStructWithAnonUnionImpl();
 }
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleUnix/UnionDeclarationTest.cs
index 89e97b78..b61bebb1 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleUnix/UnionDeclarationTest.cs
@@ -1449,6 +1449,134 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpCompatibleUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public unsafe partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        public ref IntPtr First
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct* pField = &Anonymous)
+                {{
+                    return ref pField->First;
+                }}
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &Anonymous.Anonymous)
+                {{
+                    return ref pField->A;
+                }}
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &Anonymous.Anonymous)
+                {{
+                    return ref pField->B;
+                }}
+            }}
+        }}
+
+        public unsafe partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public IntPtr First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public IntPtr Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public IntPtr Second;
+                }}
+            }}
+        }}
+
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public IntPtr e0;
+            public IntPtr e1;
+
+            public unsafe ref IntPtr this[int index]
+            {{
+                get
+                {{
+                    fixed (IntPtr* pThis = &e0)
+                    {{
+                        return ref pThis[index];
+                    }}
+                }}
+            }}
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpCompatibleUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleWindows/UnionDeclarationTest.cs
index 260b5af5..0c7f89bd 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpCompatibleWindows/UnionDeclarationTest.cs
@@ -1456,6 +1456,116 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpCompatibleWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public unsafe partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public fixed int AsArray[2];
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        public ref int First
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct* pField = &Anonymous)
+                {{
+                    return ref pField->First;
+                }}
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &Anonymous.Anonymous)
+                {{
+                    return ref pField->A;
+                }}
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &Anonymous.Anonymous)
+                {{
+                    return ref pField->B;
+                }}
+            }}
+        }}
+
+        public unsafe partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public int First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+            }}
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpCompatibleWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultUnix/UnionDeclarationTest.cs
index db6d3a6d..450dac95 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultUnix/UnionDeclarationTest.cs
@@ -1433,6 +1433,124 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpDefaultUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        public ref nint First
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.First, 1));
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.A, 1));
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.B, 1));
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public nint First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+            }}
+        }}
+
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public nint e0;
+            public nint e1;
+
+            public ref nint this[int index]
+            {{
+                get
+                {{
+                    return ref AsSpan()[index];
+                }}
+            }}
+
+            public Span<nint> AsSpan() => MemoryMarshal.CreateSpan(ref e0, 2);
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpDefaultUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultWindows/UnionDeclarationTest.cs
index 5dae51e6..fa7cbdb3 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpDefaultWindows/UnionDeclarationTest.cs
@@ -1439,6 +1439,107 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpDefaultWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public unsafe partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public fixed int AsArray[2];
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        public ref int First
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.First, 1));
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.A, 1));
+            }}
+        }}
+
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.B, 1));
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public int First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+            }}
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpDefaultWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestUnix/UnionDeclarationTest.cs
index b1a9584e..1f8fb1f1 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestUnix/UnionDeclarationTest.cs
@@ -1394,6 +1394,118 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpLatestUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        [UnscopedRef]
+        public ref nint First
+        {{
+            get
+            {{
+                return ref Anonymous.First;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.A;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.B;
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public nint First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+            }}
+        }}
+
+        [InlineArray(2)]
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public nint e0;
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpLatestUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestWindows/UnionDeclarationTest.cs
index d3379efa..4e6b0ffc 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpLatestWindows/UnionDeclarationTest.cs
@@ -1400,6 +1400,118 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpLatestWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        [UnscopedRef]
+        public ref int First
+        {{
+            get
+            {{
+                return ref Anonymous.First;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.A;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.B;
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public int First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+            }}
+        }}
+
+        [InlineArray(2)]
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public int e0;
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpLatestWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewUnix/UnionDeclarationTest.cs
index b8f83b3a..72774ebc 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewUnix/UnionDeclarationTest.cs
@@ -1394,6 +1394,118 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpPreviewUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        [UnscopedRef]
+        public ref nint First
+        {{
+            get
+            {{
+                return ref Anonymous.First;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.A;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.B;
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public nint First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public nint Second;
+                }}
+            }}
+        }}
+
+        [InlineArray(2)]
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public nint e0;
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpPreviewUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewWindows/UnionDeclarationTest.cs
index 238748cc..e102e66c 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/CSharpPreviewWindows/UnionDeclarationTest.cs
@@ -1400,6 +1400,118 @@ public partial struct MyUnion
         public {expectedManagedType} b;
     }}
 }}
+";
+
+        return ValidateGeneratedCSharpPreviewWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test
+{{
+    [StructLayout(LayoutKind.Explicit)]
+    public partial struct _MY_UNION
+    {{
+        [FieldOffset(0)]
+        [NativeTypeName(""long[2]"")]
+        public _AsArray_e__FixedBuffer AsArray;
+
+        [FieldOffset(0)]
+        [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L4_C5"")]
+        public _Anonymous_e__Struct Anonymous;
+
+        [UnscopedRef]
+        public ref int First
+        {{
+            get
+            {{
+                return ref Anonymous.First;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct A
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.A;
+            }}
+        }}
+
+        [UnscopedRef]
+        public ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct B
+        {{
+            get
+            {{
+                return ref Anonymous.Anonymous.B;
+            }}
+        }}
+
+        public partial struct _Anonymous_e__Struct
+        {{
+            [NativeTypeName(""long"")]
+            public int First;
+
+            [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L7_C9"")]
+            public _Anonymous_e__Union Anonymous;
+
+            [StructLayout(LayoutKind.Explicit)]
+            public partial struct _Anonymous_e__Union
+            {{
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L9_C13"")]
+                public _A_e__Struct A;
+
+                [FieldOffset(0)]
+                [NativeTypeName(""__AnonymousRecord_ClangUnsavedFile_L14_C13"")]
+                public _B_e__Struct B;
+
+                public partial struct _A_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+
+                public partial struct _B_e__Struct
+                {{
+                    [NativeTypeName(""long"")]
+                    public int Second;
+                }}
+            }}
+        }}
+
+        [InlineArray(2)]
+        public partial struct _AsArray_e__FixedBuffer
+        {{
+            public int e0;
+        }}
+    }}
+}}
 ";
 
         return ValidateGeneratedCSharpPreviewWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleUnix/UnionDeclarationTest.cs
index d95cb143..07b48d38 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleUnix/UnionDeclarationTest.cs
@@ -1338,6 +1338,120 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlCompatibleUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" unsafe=""true"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">IntPtr</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref IntPtr</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct* pField = &amp;Anonymous)
+    {{
+        return ref pField-&gt;First;
+    }}</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &amp;Anonymous.Anonymous)
+    {{
+        return ref pField-&gt;A;
+    }}</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &amp;Anonymous.Anonymous)
+    {{
+        return ref pField-&gt;B;
+    }}</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"" unsafe=""true"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">IntPtr</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">IntPtr</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">IntPtr</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <field name=""e0"" access=""public"">
+          <type>IntPtr</type>
+        </field>
+        <field name=""e1"" access=""public"">
+          <type>IntPtr</type>
+        </field>
+        <indexer access=""public"" unsafe=""true"">
+          <type>ref IntPtr</type>
+          <param name=""index"">
+            <type>int</type>
+          </param>
+          <get>
+            <code>fixed (IntPtr* pThis = &amp;e0)
+    {{
+        return ref pThis[index];
+    }}</code>
+          </get>
+        </indexer>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlCompatibleUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleWindows/UnionDeclarationTest.cs
index 97cf46ce..3e1ae4f3 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlCompatibleWindows/UnionDeclarationTest.cs
@@ -1344,6 +1344,100 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlCompatibleWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" unsafe=""true"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">int</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref int</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct* pField = &amp;Anonymous)
+    {{
+        return ref pField-&gt;First;
+    }}</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &amp;Anonymous.Anonymous)
+    {{
+        return ref pField-&gt;A;
+    }}</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>fixed (_Anonymous_e__Struct._Anonymous_e__Union* pField = &amp;Anonymous.Anonymous)
+    {{
+        return ref pField-&gt;B;
+    }}</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"" unsafe=""true"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">int</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlCompatibleWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultUnix/UnionDeclarationTest.cs
index 3b39053e..14b87e28 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultUnix/UnionDeclarationTest.cs
@@ -1324,6 +1324,112 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlDefaultUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">nint</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref nint</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.First, 1));</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.A, 1));</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.B, 1));</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">nint</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <field name=""e0"" access=""public"">
+          <type>nint</type>
+        </field>
+        <field name=""e1"" access=""public"">
+          <type>nint</type>
+        </field>
+        <indexer access=""public"">
+          <type>ref nint</type>
+          <param name=""index"">
+            <type>int</type>
+          </param>
+          <get>
+            <code>return ref AsSpan()[index];</code>
+          </get>
+        </indexer>
+        <function name=""AsSpan"" access=""public"">
+          <type>Span&lt;nint&gt;</type>
+          <code>MemoryMarshal.CreateSpan(ref e0, 2);</code>
+        </function>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlDefaultUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultWindows/UnionDeclarationTest.cs
index 6064c700..74231b71 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlDefaultWindows/UnionDeclarationTest.cs
@@ -1330,6 +1330,91 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlDefaultWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" unsafe=""true"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">int</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref int</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.First, 1));</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.A, 1));</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref MemoryMarshal.GetReference(MemoryMarshal.CreateSpan(ref Anonymous.Anonymous.B, 1));</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">int</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlDefaultWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestUnix/UnionDeclarationTest.cs
index 456dea7c..d989592e 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestUnix/UnionDeclarationTest.cs
@@ -1213,6 +1213,97 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlLatestUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">nint</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref nint</type>
+        <get>
+          <code>return ref Anonymous.First;</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.A;</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.B;</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">nint</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <attribute>InlineArray(2)</attribute>
+        <field name=""e0"" access=""public"">
+          <type>nint</type>
+        </field>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlLatestUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestWindows/UnionDeclarationTest.cs
index 85d7ac1e..1fda6ad0 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlLatestWindows/UnionDeclarationTest.cs
@@ -1219,6 +1219,97 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlLatestWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">int</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref int</type>
+        <get>
+          <code>return ref Anonymous.First;</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.A;</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.B;</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">int</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <attribute>InlineArray(2)</attribute>
+        <field name=""e0"" access=""public"">
+          <type>int</type>
+        </field>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlLatestWindowsBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewUnix/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewUnix/UnionDeclarationTest.cs
index f2b921fb..18afdd60 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewUnix/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewUnix/UnionDeclarationTest.cs
@@ -1213,6 +1213,97 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlPreviewUnixBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">nint</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref nint</type>
+        <get>
+          <code>return ref Anonymous.First;</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.A;</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.B;</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">nint</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">nint</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <attribute>InlineArray(2)</attribute>
+        <field name=""e0"" access=""public"">
+          <type>nint</type>
+        </field>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlPreviewUnixBindingsAsync(inputContents, expectedOutputContents);
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewWindows/UnionDeclarationTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewWindows/UnionDeclarationTest.cs
index d9cdd573..92e1245d 100644
--- a/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewWindows/UnionDeclarationTest.cs
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/XmlPreviewWindows/UnionDeclarationTest.cs
@@ -1219,6 +1219,97 @@ union MyUnion
     </struct>
   </namespace>
 </bindings>
+";
+
+        return ValidateGeneratedXmlPreviewWindowsBindingsAsync(inputContents, expectedOutputContents);
+    }
+
+    protected override Task UnionWithAnonStructWithAnonUnionImpl()
+    {
+        var inputContents = $@"typedef union _MY_UNION
+{{
+    long AsArray[2];
+    struct
+    {{
+        long First;
+        union
+        {{
+            struct
+            {{
+                long Second;
+            }} A;
+
+            struct
+            {{
+                long Second;
+            }} B;
+        }};
+    }};
+}} MY_UNION;";
+
+        var expectedOutputContents = $@"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes"" ?>
+<bindings>
+  <namespace name=""ClangSharp.Test"">
+    <struct name=""_MY_UNION"" access=""public"" layout=""Explicit"">
+      <field name=""AsArray"" access=""public"" offset=""0"">
+        <type native=""long[2]"" count=""2"" fixed=""_AsArray_e__FixedBuffer"">int</type>
+      </field>
+      <field name=""Anonymous"" access=""public"" offset=""0"">
+        <type native=""__AnonymousRecord_ClangUnsavedFile_L4_C5"">_Anonymous_e__Struct</type>
+      </field>
+      <field name=""First"" access=""public"">
+        <type>ref int</type>
+        <get>
+          <code>return ref Anonymous.First;</code>
+        </get>
+      </field>
+      <field name=""A"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._A_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.A;</code>
+        </get>
+      </field>
+      <field name=""B"" access=""public"">
+        <type>ref _Anonymous_e__Struct._Anonymous_e__Union._B_e__Struct</type>
+        <get>
+          <code>return ref Anonymous.Anonymous.B;</code>
+        </get>
+      </field>
+      <struct name=""_Anonymous_e__Struct"" access=""public"">
+        <field name=""First"" access=""public"">
+          <type native=""long"">int</type>
+        </field>
+        <field name=""Anonymous"" access=""public"">
+          <type native=""__AnonymousRecord_ClangUnsavedFile_L7_C9"">_Anonymous_e__Union</type>
+        </field>
+        <struct name=""_Anonymous_e__Union"" access=""public"" layout=""Explicit"">
+          <field name=""A"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L9_C13"">_A_e__Struct</type>
+          </field>
+          <field name=""B"" access=""public"" offset=""0"">
+            <type native=""__AnonymousRecord_ClangUnsavedFile_L14_C13"">_B_e__Struct</type>
+          </field>
+          <struct name=""_A_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+          <struct name=""_B_e__Struct"" access=""public"">
+            <field name=""Second"" access=""public"">
+              <type native=""long"">int</type>
+            </field>
+          </struct>
+        </struct>
+      </struct>
+      <struct name=""_AsArray_e__FixedBuffer"" access=""public"">
+        <attribute>InlineArray(2)</attribute>
+        <field name=""e0"" access=""public"">
+          <type>int</type>
+        </field>
+      </struct>
+    </struct>
+  </namespace>
+</bindings>
 ";
 
         return ValidateGeneratedXmlPreviewWindowsBindingsAsync(inputContents, expectedOutputContents);