Add _AsValue accessors for blittable nested struct properties

README.md

@@ -129,5 +129,6 @@ Blittable structs are stored directly as raw struct bytes without an offset tabl
 - Validate integrity or authenticity before creating a View when required.
 - The wire format requires a little-endian runtime.
 - View structs expose a compile-time constant `IsBlittable`, indicating whether the underlying serialized type is a blittable struct.
+- Nested blittable struct properties on blittable Views expose both a zero-copy View property and a `{PropertyName}_AsValue` property that reads the struct value from serialized memory.
 - You can use `.AsMemory()` extension method (returns `ReadOnlyMemory<byte>`) or `.Materialize()` extension method (for views of blittable structs to convert them back to the original struct).
 - Nested classes and structs must be marked with `[ZeroSerializer]`; otherwise the generator reports an unsupported property diagnostic.

src/ZeroSerializerGenerator.cs

@@ -1283,9 +1283,21 @@ var propertyReturnType
                 && property.NestedSerializableType is not null)
             {
                 sourceBuilder.AppendLine($"return new {GetQualifiedViewName(property.NestedSerializableType)}(serializedMemory.Slice({property.BlittableByteOffset}, {property.ElementByteCount}));");
+                sourceBuilder.CloseBlock();
+                sourceBuilder.CloseBlock();
+                sourceBuilder.AppendLine();
+                sourceBuilder.AppendLine($"{propertyAccessibility} {property.Symbol.Type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)} {EscapeIdentifier(property.Symbol.Name + "_AsValue")}");
+                sourceBuilder.OpenBlock();
+                sourceBuilder.AppendLine("get");
+                sourceBuilder.OpenBlock();
+                sourceBuilder.AppendLine($"return MemoryMarshal.Read<{GetSerializedPropertyType(property).ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)}>(serializedMemory.Span.Slice({property.BlittableByteOffset}, {property.ElementByteCount}));");
+                sourceBuilder.CloseBlock();
+                sourceBuilder.CloseBlock();
+                return;
             }
             else
             {
+                sourceBuilder.AppendLine("// Fallback generated unexpectedly. According to the specification, this fallback should not be reached (the view always returns the view in any case).");
                 sourceBuilder.AppendLine($"{containingModel.QualifiedSourceTypeName} blittableSourceValue = MemoryMarshal.Read<{containingModel.QualifiedSourceTypeName}>(serializedMemory.Span);");
                 sourceBuilder.AppendLine($"return blittableSourceValue.{EscapeIdentifier(property.Symbol.Name)};");
             }

tests/SerializationModels.cs

@@ -76,7 +76,7 @@
 }
 
 [ZeroSerializer]
 public readonly struct EnumStruct
 {
     public EnumStruct(ByteState byteState, SignedState signedState)
     {
@@ -149,7 +149,7 @@
 }
 
 [ZeroSerializer]
 public readonly struct SmallFixedStruct
 {
     public SmallFixedStruct(int value)
     {
@@ -160,7 +160,7 @@
 }
 
 [ZeroSerializer]
 public readonly struct LargeFixedStruct
 {
     public LargeFixedStruct(long value, ByteState state)
     {
@@ -294,6 +294,13 @@
     public int Value { get; init; }
 }
 
+[StructLayout(LayoutKind.Sequential, Pack = 1)]
+[ZeroSerializer]
+public struct StrictBlittableStructWithNestedProperty
+{
+    public PackedRecord Nested { get; init; }
+}
+
 [ZeroSerializer]
 public sealed class NullableStructContainerModel
 {

tests/SerializationTests.cs

@@ -765,7 +765,7 @@ public void PrimitiveAndEnumArraysSerializeAndDeserializeCorrectly()
     }
 
     [Fact]
-    public void NestedSerializableTypePropertiesReturnViewStructInstances()
+    public void NestedSerializableTypePropertiesExposeExpectedViewAndValueAccessors()
     {
         // 1. Assert that nested blittable type returns view
         PropertyInfo? valueProperty = typeof(PackedContainerView).GetProperty(nameof(PackedContainerView.Value));
@@ -776,12 +776,44 @@ public void NestedSerializableTypePropertiesReturnViewStructInstances()
         Assert.NotNull(optionalValueProperty);
         Assert.Equal(typeof(Nullable<PackedRecordView>), optionalValueProperty!.PropertyType);
 
+        PropertyInfo? valueAsValueProperty = typeof(StrictBlittableStructWithNestedPropertyView).GetProperty(nameof(StrictBlittableStructWithNestedPropertyView.Nested_AsValue));
+        Assert.NotNull(valueAsValueProperty);
+        Assert.Equal(typeof(PackedRecord), valueAsValueProperty!.PropertyType);
+
+        var source = new StrictBlittableStructWithNestedProperty
+        {
+            Nested = new PackedRecord { Number = 42, State = SignedState.Positive }
+        };
+        byte[] buffer = new byte[StrictBlittableStructWithNestedPropertyView.RequiredByteLength];
+        source.Serialize(buffer);
+        var view = new StrictBlittableStructWithNestedPropertyView(buffer);
+        TestAssert.Equal(42, view.Nested.Number, "Nested view Number");
+        TestAssert.Equal(SignedState.Positive, view.Nested.State, "Nested view State");
+        TestAssert.Equal(42, view.Nested_AsValue.Number, "Nested value Number");
+        TestAssert.Equal(SignedState.Positive, view.Nested_AsValue.State, "Nested value State");
+
         // 2. Assert that nested non-blittable type returns view
         PropertyInfo? childProperty = typeof(VariableRecordView).GetProperty(nameof(VariableRecordView.Child));
         Assert.NotNull(childProperty);
         Assert.Equal(typeof(FixedClassView?), childProperty!.PropertyType);
     }
 
+    [Fact]
+    public void NonBlittableViewsWithBlittableAndNonBlittablePropertiesDoNotExposeAsValueAccessors()
+    {
+        TestAssert.True(!NullableStructContainerModelView.IsBlittable, "The combined-property View is non-blittable");
+
+        PropertyInfo? blittableValueProperty = typeof(NullableStructContainerModelView).GetProperty("BlittableStruct_AsValue");
+        PropertyInfo? nullableBlittableValueProperty = typeof(NullableStructContainerModelView).GetProperty("NullableBlittableStruct_AsValue");
+        PropertyInfo? nonBlittableValueProperty = typeof(NullableStructContainerModelView).GetProperty("NonBlittableStruct_AsValue");
+        PropertyInfo? nullableNonBlittableValueProperty = typeof(NullableStructContainerModelView).GetProperty("NullableNonBlittableStruct_AsValue");
+
+        Assert.Null(blittableValueProperty);
+        Assert.Null(nullableBlittableValueProperty);
+        Assert.Null(nonBlittableValueProperty);
+        Assert.Null(nullableNonBlittableValueProperty);
+    }
+
     [Fact]
     public void StrictBlittableStructWithoutOffsetTableSerializesAsRawPayload()
     {