Use switch expression in IsTypeIdColumn method

Author: AlexUstinov

Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs

@@ -166,15 +166,12 @@ private static bool IsColumnStub(SqlColumn column)
       return column is SqlColumnRef columnRef && columnRef.SqlColumn is SqlColumnStub;
     }
 
-    private static bool IsTypeIdColumn(SqlColumn column)
-    {
-      if (column is SqlUserColumn)
-        return string.Equals(column.Name, "TypeId", StringComparison.OrdinalIgnoreCase);
-      var cRef = column as SqlColumnRef;
-      if (!ReferenceEquals(null, cRef))
-        return string.Equals(cRef.Name, "TypeId", StringComparison.OrdinalIgnoreCase);
-      return false;
-    }
+    private static bool IsTypeIdColumn(SqlColumn column) =>
+      column switch {
+        SqlUserColumn _ => string.Equals(column.Name, "TypeId", StringComparison.OrdinalIgnoreCase),
+        SqlColumnRef cRef => string.Equals(cRef.Name, "TypeId", StringComparison.OrdinalIgnoreCase),
+        _ => false
+      };
 
     private static SqlColumnStub ExtractColumnStub(SqlColumn column) =>
       column switch {
@@ -290,7 +287,7 @@ private static bool ShouldUseQueryReference(CompilableProvider origin, SqlProvid
           return orderingOverCalculatedColumn;
         }
         default:
-          var typeIdIsOnlyCalculatedColumn = containsCalculatedColumns && (calculatedColumnIndexes.Count == 1)
+          var typeIdIsOnlyCalculatedColumn = containsCalculatedColumns && calculatedColumnIndexes.Count == 1
             && IsTypeIdColumn(sourceSelect.Columns[calculatedColumnIndexes[0]]);
           return (containsCalculatedColumns && !typeIdIsOnlyCalculatedColumn) || distinctIsUsed || pagingIsUsed || groupByIsUsed;
       }