Create AutoPropertyBackingFieldSymbol.cs

src/Draco.Compiler/Internal/Symbols/Synthetized/AutoProperty/AutoPropertyBackingFieldSymbol.cs

@@ -0,0 +1,22 @@
+namespace Draco.Compiler.Internal.Symbols.Synthetized.AutoProperty;
+
+/// <summary>
+/// Auto-generated backing field for an auto-property.
+/// </summary>
+internal sealed class AutoPropertyBackingFieldSymbol(
+    TypeSymbol containingSymbol,
+    PropertySymbol property) : FieldSymbol
+{
+    public override TypeSymbol ContainingSymbol { get; } = containingSymbol;
+
+    public override TypeSymbol Type => this.Property.Type;
+    public override bool IsStatic => this.Property.IsStatic;
+    public override bool IsMutable => this.Property.Setter is not null;
+    public override string Name => $"<{this.Property.Name}>_BackingField";
+    public override Api.Semantics.Visibility Visibility => Api.Semantics.Visibility.Private;
+
+    /// <summary>
+    /// The property this backing field is for.
+    /// </summary>
+    public PropertySymbol Property { get; } = property;
+}