Work on Cosmos primitive collections, subquery and general query infra

src/EFCore.Cosmos/Properties/CosmosStrings.resx

@@ -123,9 +123,6 @@
   <data name="CanConnectNotSupported" xml:space="preserve">
     <value>The Cosmos database does not support 'CanConnect' or 'CanConnectAsync'.</value>
   </data>
-  <data name="CannotTranslateNonConstantNewArrayExpression" xml:space="preserve">
-    <value>The query contained a new array expression containing non-constant elements, which could not be translated: '{newArrayExpression}'.</value>
-  </data>
   <data name="ConnectionInfoMissing" xml:space="preserve">
     <value>None of connection string, CredentialToken, account key or account endpoint were specified. Specify a set of connection details.</value>
   </data>
@@ -144,6 +141,9 @@
   <data name="ETagNonStringStoreType" xml:space="preserve">
     <value>The type of the etag property '{property}' on '{entityType}' is '{propertyType}'. All etag properties must be strings or have a string value converter.</value>
   </data>
+  <data name="ExceptNotSupported" xml:space="preserve">
+    <value>The 'Except()' LINQ operator isn't supported by Cosmos.</value>
+  </data>
   <data name="IdNonStringStoreType" xml:space="preserve">
     <value>The type of the '{idProperty}' property on '{entityType}' is '{propertyType}'. All 'id' properties must be strings or have a string value converter.</value>
   </data>
@@ -213,6 +213,9 @@
   <data name="NoIdProperty" xml:space="preserve">
     <value>The entity type '{entityType}' does not have a property mapped to the 'id' property in the database. Add a property mapped to 'id'.</value>
   </data>
+  <data name="NonCorrelatedSubqueriesNotSupported" xml:space="preserve">
+    <value>Cosmos subqueries must be correlated, referencing values from the outer query.</value>
+  </data>
   <data name="NonEmbeddedIncludeNotSupported" xml:space="preserve">
     <value>Including navigation '{navigation}' is not supported as the navigation is not embedded in same resource.</value>
   </data>

src/EFCore.Cosmos/Query/Internal/CosmosQueryRootProcessor.cs

@@ -0,0 +1,56 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.Cosmos.Query.Internal;
+
+/// <summary>
+///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+///     any release. You should only use it directly in your code with extreme caution and knowing that
+///     doing so can result in application failures when updating to a new Entity Framework Core release.
+/// </summary>
+public class CosmosQueryRootProcessor : QueryRootProcessor
+{
+    private readonly IModel _model;
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public CosmosQueryRootProcessor(QueryTranslationPreprocessorDependencies dependencies, QueryCompilationContext queryCompilationContext)
+        : base(dependencies, queryCompilationContext)
+    {
+        _model = queryCompilationContext.Model;
+    }
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    protected override bool ShouldConvertToInlineQueryRoot(Expression expression)
+        => true;
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    protected override bool ShouldConvertToParameterQueryRoot(ParameterExpression parameterExpression)
+        => true;
+
+    /// <inheritdoc />
+    protected override Expression VisitExtension(Expression node)
+        => node switch
+        {
+            // We skip FromSqlQueryRootExpression, since that contains the arguments as an object array parameter, and don't want to convert
+            // that to a query root
+            FromSqlQueryRootExpression e => e,
+
+            _ => base.VisitExtension(node)
+        };
+}