Fix SQL DML Clone correctness bugs

Orm/Xtensive.Orm/Sql/Dml/Collections/SqlInsertValuesCollection.cs

@@ -123,7 +123,7 @@ internal SqlInsertValuesCollection Clone(SqlNodeCloneContext context)
 
       clone.rows = new List<SqlRow>(rows.Count);
       foreach(var oldRow in rows) {
-        clone.rows.Add((SqlRow) oldRow.Clone());
+        clone.rows.Add(oldRow.Clone(context));
       }
 
       return clone;

Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlConcat.cs

@@ -14,19 +14,14 @@ namespace Xtensive.Sql.Dml
   [Serializable]
   public class SqlConcat : SqlExpressionList
   {
-    internal override SqlConcat Clone(SqlNodeCloneContext context)
-    {
-      if (context.NodeMapping.TryGetValue(this, out var value)) {
-        return (SqlConcat)value;
-      }
-
-      var expressionsClone = new List<SqlExpression>(expressions.Count);
-      foreach (var e in expressions)
-        expressionsClone.Add(e.Clone(context));
-
-      var clone = new SqlConcat(expressionsClone);
-      return clone;
-    }
+    internal override SqlConcat Clone(SqlNodeCloneContext context) =>
+      context.GetOrAdd(this, static (t, c) => {
+        var source = t.expressions;
+        var expressionsClone = new SqlExpression[source.Count];
+        for (int i = 0; i < source.Count; i++)
+          expressionsClone[i] = source[i].Clone(c);
+        return new SqlConcat(expressionsClone);
+      });
 
     public override void ReplaceWith(SqlExpression expression)
     {

Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRow.cs

@@ -4,28 +4,21 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
 {
   [Serializable]
   public class SqlRow: SqlExpressionList
   {
-    internal override SqlRow Clone(SqlNodeCloneContext context)
-    {
-      if (context.TryGet(this) is SqlRow value) {
-        return value;
-      }
-
-      var expressionsClone = new List<SqlExpression>(expressions.Count);
-      foreach (var e in expressions)
-        expressionsClone.Add(e.Clone(context));
-
-      var clone = new SqlRow(expressionsClone);
-      return clone;
-    }
-
+    internal override SqlRow Clone(SqlNodeCloneContext context) =>
+      context.GetOrAdd(this, static (t, c) => {
+        var source = t.expressions;
+        var expressionsClone = new SqlExpression[source.Count];
+        for (int i = 0; i < source.Count; i++)
+          expressionsClone[i] = source[i].Clone(c);
+        return new SqlRow(expressionsClone);
+      });
 
     public override void ReplaceWith(SqlExpression expression)
     {

Orm/Xtensive.Orm/Sql/Dml/Hints/SqlForceJoinOrderHint.cs

@@ -3,9 +3,7 @@
 // See the License.txt file in the project root for more information.
 
 using System;
-using System.Linq;
 using System.Collections.Generic;
-using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
 {
@@ -20,8 +18,15 @@ public class SqlForceJoinOrderHint : SqlHint
     public IEnumerable<SqlTable> Tables { get { return tables; } }
 
     internal override SqlForceJoinOrderHint Clone(SqlNodeCloneContext context) =>
-      context.GetOrAdd(this, static (t, c) =>
-        new SqlForceJoinOrderHint(t.tables?.SelectToArray(table => (SqlTable) table.Clone())));
+      context.GetOrAdd(this, static (t, c) => {
+        if (t.tables is null)
+          return new SqlForceJoinOrderHint();
+        var source = t.tables;
+        var tablesClone = new SqlTable[source.Length];
+        for (int i = 0; i < source.Length; i++)
+          tablesClone[i] = source[i].Clone(c);
+        return new SqlForceJoinOrderHint(tablesClone);
+      });
 
     public override void AcceptVisitor(ISqlVisitor visitor)
     {

Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinHint.cs

@@ -24,8 +24,7 @@ public class SqlJoinHint : SqlHint
     public SqlTable Table { get; private set; }
 
     internal override SqlJoinHint Clone(SqlNodeCloneContext context) =>
-      context.GetOrAdd(this, static (t, c) =>
-        new SqlJoinHint(t.Method, (SqlTable) t.Table.Clone()));
+      context.GetOrAdd(this, static (t, c) => new(t.Method, (SqlTable) t.Table.Clone(c)));
 
     public override void AcceptVisitor(ISqlVisitor visitor)
     {

Orm/Xtensive.Orm/Sql/Dml/Statements/SqlSelect.cs

@@ -204,8 +204,8 @@ internal override SqlSelect Clone(SqlNodeCloneContext context) =>
           foreach (SqlOrder so in t.orderBy)
             clone.OrderBy.Add(so.Clone(c));
         clone.Distinct = t.distinct;
-        clone.Limit = t.Limit;
-        clone.Offset = t.Offset;
+        clone.Limit = t.Limit?.Clone(c);
+        clone.Offset = t.Offset?.Clone(c);
         clone.Lock = t.Lock;
         clone.Comment = t.Comment?.Clone(c);
 

Orm/Xtensive.Orm/Sql/Dml/Statements/SqlUpdate.cs

@@ -80,7 +80,7 @@ internal override SqlUpdate Clone(SqlNodeCloneContext context) =>
         if (t.where is not null)
           clone.Where = t.where.Clone(c);
         if (t.limit is not null)
-          clone.Limit = t.where.Clone(c);
+          clone.Limit = t.limit.Clone(c);
         if (t.Hints.Count > 0)
           foreach (SqlHint hint in t.Hints)
             clone.Hints.Add((SqlHint) hint.Clone(c));