SQL search renaming/refactoring

CustomAnalysisRules.ruleset

@@ -15,12 +15,14 @@
     <Rule Id="SA1101" Action="None" />
     <Rule Id="SA1308" Action="None" />
     <Rule Id="SA1309" Action="None" />
+    <Rule Id="SA1405" Action="None" />
     <Rule Id="SA1512" Action="None" />
     <Rule Id="SA1600" Action="None" />
     <Rule Id="SA1602" Action="None" />
     <Rule Id="SA1615" Action="None" />
     <Rule Id="SA1623" Action="None" />
     <Rule Id="SA1629" Action="None" />
+    <Rule Id="SA1642" Action="None" />
     <Rule Id="SA1652" Action="None" />
   </Rules>
   <Rules AnalyzerId="Microsoft.CodeQuality.Analyzers" RuleNamespace="Microsoft.CodeQuality.Analyzers">

src/Microsoft.Health.Fhir.Core/Features/Search/Expressions/ExpressionRewriter.cs

@@ -137,5 +137,28 @@ protected static void EnsureAllocatedAndPopulated<TExpression>(ref List<TExpress
                 }
             }
         }
+
+        /// <summary>
+        /// Like <see cref="EnsureAllocatedAndPopulated{TExpression}(ref TExpression[],System.Collections.Generic.IReadOnlyList{TExpression},int)"/>,
+        /// but where the destination list if is of a derived type
+        /// </summary>
+        /// <typeparam name="TDestination">The destination list type</typeparam>
+        /// <typeparam name="TSource">The source list type</typeparam>
+        /// <param name="destination">The destination list to allocate and populate</param>
+        /// <param name="source">The source list</param>
+        /// <param name="count">The number of elements from source to copy to destination</param>
+        protected static void EnsureAllocatedAndPopulatedChangeType<TDestination, TSource>(ref List<TDestination> destination, IReadOnlyList<TSource> source, int count)
+            where TSource : Expression
+            where TDestination : TSource
+        {
+            if (destination == null)
+            {
+                destination = new List<TDestination>();
+                for (int j = 0; j < count; j++)
+                {
+                    destination.Add((TDestination)source[j]);
+                }
+            }
+        }
     }
 }