Optimize ColumnInfoRef

Author: SergeiPavlov

Orm/Xtensive.Orm/Orm/Model/ColumnInfoRef.cs

@@ -40,8 +40,6 @@ namespace Xtensive.Orm.Model
     /// </summary>
     public CultureInfo CultureInfo { get; }
 
-    public bool HasValue => TypeName != null;
-
     /// <summary>
     /// Resolves this instance to <see cref="ColumnInfo"/> object within specified <paramref name="model"/>.
     /// </summary>

Orm/Xtensive.Orm/Orm/Rse/MappedColumn.cs

@@ -17,10 +17,11 @@ public sealed class MappedColumn : Column
   {
     private const string ToStringFormat = "{0} = {1}";
 
+    private readonly ColumnInfoRef _columnInfo;
     /// <summary>
     /// Gets the reference that describes a column.
     /// </summary>    
-    public ColumnInfoRef ColumnInfoRef { get; }
+    public ref readonly ColumnInfoRef ColumnInfoRef => ref _columnInfo;
 
     /// <inheritdoc/>
     public override string ToString()
@@ -76,7 +77,7 @@ public MappedColumn(in ColumnInfoRef columnInfoRef, int index, Type type)
     public MappedColumn(in ColumnInfoRef columnInfoRef, string name, int index, Type type)
       : base(name, index, type, null)
     {
-      ColumnInfoRef = columnInfoRef;
+      _columnInfo = columnInfoRef;
     }
 
     #endregion
@@ -86,13 +87,13 @@ public MappedColumn(in ColumnInfoRef columnInfoRef, string name, int index, Type
     private MappedColumn(MappedColumn column, string newName)
       : base(newName, column.Index, column.Type, column)
     {
-      ColumnInfoRef = column.ColumnInfoRef;
+      _columnInfo = column.ColumnInfoRef;
     }
 
     private MappedColumn(MappedColumn column, int newIndex)
       : base(column.Name, newIndex, column.Type, column)
     {
-      ColumnInfoRef = column.ColumnInfoRef;
+      _columnInfo = column.ColumnInfoRef;
     }
 
     #endregion

Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/OrderProviderBase.cs

@@ -67,10 +67,7 @@ protected override void Initialize()
       for (int i = 0; i < Order.Count; i++) {
         var orderItem = Order[i];
         var column = Header.Columns[orderItem.Key];
-        var columnInfoRef = (column as MappedColumn)?.ColumnInfoRef;
-        var culture = columnInfoRef?.HasValue == true
-            ? columnInfoRef.Value.CultureInfo
-            : CultureInfo.InvariantCulture;
+        var culture = (column as MappedColumn)?.ColumnInfoRef.CultureInfo ?? CultureInfo.InvariantCulture;
         comparisonRules[i] = new ComparisonRule(orderItem.Value, culture);
       }