Introduce liftable constants to shaper to prepare for precompilation.

Fix materializer code to replace non-primitive constants with liftable constants.
Precompilation is opt-in in QueryCompilationContext, switched on for relational, off for everything else.

Architecture, design and initial implementation done by @roji, polish done by @maumar

Part of #25009

EFCore.sln.DotSettings

@@ -309,6 +309,7 @@ The .NET Foundation licenses this file to you under the MIT license.
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Includable/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=initializers/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=keyless/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=liftable/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Lite_0027s/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=materializer/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=materializers/@EntryIndexedValue">True</s:Boolean>

src/EFCore.InMemory/Query/Internal/InMemoryQueryExpression.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.EntityFrameworkCore.InMemory.Internal;
-using Microsoft.EntityFrameworkCore.Internal;
 using ExpressionExtensions = Microsoft.EntityFrameworkCore.Infrastructure.ExpressionExtensions;
 
 namespace Microsoft.EntityFrameworkCore.InMemory.Query.Internal;

src/EFCore.Relational/Infrastructure/EntityFrameworkRelationalServicesBuilder.cs

@@ -63,6 +63,7 @@ public static readonly IDictionary<Type, ServiceCharacteristics> RelationalServi
             { typeof(IQuerySqlGeneratorFactory), new ServiceCharacteristics(ServiceLifetime.Singleton) },
             { typeof(IModificationCommandFactory), new ServiceCharacteristics(ServiceLifetime.Singleton) },
             { typeof(ISqlAliasManagerFactory), new ServiceCharacteristics(ServiceLifetime.Singleton) },
+            { typeof(IRelationalLiftableConstantFactory), new ServiceCharacteristics(ServiceLifetime.Singleton) },
             { typeof(ICommandBatchPreparer), new ServiceCharacteristics(ServiceLifetime.Scoped) },
             { typeof(IModificationCommandBatchFactory), new ServiceCharacteristics(ServiceLifetime.Scoped) },
             { typeof(IRelationalSqlTranslatingExpressionVisitorFactory), new ServiceCharacteristics(ServiceLifetime.Scoped) },
@@ -189,6 +190,9 @@ public override EntityFrameworkServicesBuilder TryAddCoreServices()
         TryAdd<IQueryCompilationContextFactory, RelationalQueryCompilationContextFactory>();
         TryAdd<IAdHocMapper, RelationalAdHocMapper>();
         TryAdd<ISqlAliasManagerFactory, SqlAliasManagerFactory>();
+        TryAdd<ILiftableConstantFactory>(p => p.GetRequiredService<IRelationalLiftableConstantFactory>());
+        TryAdd<IRelationalLiftableConstantFactory, RelationalLiftableConstantFactory>();
+        TryAdd<ILiftableConstantProcessor, RelationalLiftableConstantProcessor>();
 
         ServiceCollectionMap.GetInfrastructure()
             .AddDependencySingleton<RelationalSqlGenerationHelperDependencies>()
@@ -204,6 +208,7 @@ public override EntityFrameworkServicesBuilder TryAddCoreServices()
             .AddDependencySingleton<RelationalEvaluatableExpressionFilterDependencies>()
             .AddDependencySingleton<RelationalModelDependencies>()
             .AddDependencySingleton<RelationalModelRuntimeInitializerDependencies>()
+            .AddDependencySingleton<RelationalLiftableConstantExpressionDependencies>()
             .AddDependencyScoped<MigrationsSqlGeneratorDependencies>()
             .AddDependencyScoped<RelationalConventionSetBuilderDependencies>()
             .AddDependencyScoped<ModificationCommandBatchFactoryDependencies>()

src/EFCore.Relational/Query/IRelationalLiftableConstantFactory.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.EntityFrameworkCore.Query;
+
+/// <summary>
+///     This is an experimental API used by the Entity Framework Core feature and it is 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>
+[Experimental(EFDiagnostics.PrecompiledQueryExperimental)]
+public interface IRelationalLiftableConstantFactory : ILiftableConstantFactory
+{
+    /// <summary>
+    ///     This is an experimental API used by the Entity Framework Core feature and it is 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>
+    LiftableConstantExpression CreateLiftableConstant(
+        object? originalValue,
+        Expression<Func<RelationalMaterializerLiftableConstantContext, object>> resolverExpression,
+        string variableName,
+        Type type);
+}

src/EFCore.Relational/Query/Internal/BufferedDataReader.cs

@@ -836,10 +836,7 @@ public ulong GetUInt64(int ordinal)
         public object GetValue(int ordinal)
             => GetFieldValue<object>(ordinal);
 
-#pragma warning disable IDE0060 // Remove unused parameter
-        public static int GetValues(object[] values)
-#pragma warning restore IDE0060 // Remove unused parameter
-            => throw new NotSupportedException();
+        public static int GetValues(object[] values) => throw new NotSupportedException();
 
         public T GetFieldValue<T>(int ordinal)
             => (_columnTypeCases[ordinal]) switch

src/EFCore.Relational/Query/Internal/FromSqlQueryingEnumerable.cs

@@ -6,6 +6,42 @@
 
 namespace Microsoft.EntityFrameworkCore.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 static class FromSqlQueryingEnumerable
+{
+    /// <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 static FromSqlQueryingEnumerable<T> Create<T>(
+        RelationalQueryContext relationalQueryContext,
+        RelationalCommandCache relationalCommandCache,
+        IReadOnlyList<ReaderColumn?>? readerColumns,
+        IReadOnlyList<string> columnNames,
+        Func<QueryContext, DbDataReader, int[], T> shaper,
+        Type contextType,
+        bool standAloneStateManager,
+        bool detailedErrorsEnabled,
+        bool threadSafetyChecksEnabled)
+        => new(
+            relationalQueryContext,
+            relationalCommandCache,
+            readerColumns,
+            columnNames,
+            shaper,
+            contextType,
+            standAloneStateManager,
+            detailedErrorsEnabled,
+            threadSafetyChecksEnabled);
+}
+
 /// <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

src/EFCore.Relational/Query/Internal/GroupBySingleQueryingEnumerable.cs

@@ -20,7 +20,7 @@ public class GroupBySingleQueryingEnumerable<TKey, TElement>
     private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
     private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
     private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-    private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+    private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
     private readonly Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, TElement> _elementSelector;
     private readonly Type _contextType;
     private readonly IDiagnosticsLogger<DbLoggerCategory.Query> _queryLogger;
@@ -40,7 +40,7 @@ public GroupBySingleQueryingEnumerable(
         IReadOnlyList<ReaderColumn?>? readerColumns,
         Func<QueryContext, DbDataReader, TKey> keySelector,
         Func<QueryContext, DbDataReader, object[]> keyIdentifier,
-        IReadOnlyList<ValueComparer> keyIdentifierValueComparers,
+        IReadOnlyList<Func<object, object, bool>> keyIdentifierValueComparers,
         Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, TElement> elementSelector,
         Type contextType,
         bool standAloneStateManager,
@@ -139,12 +139,12 @@ IEnumerator IEnumerable.GetEnumerator()
             => GetEnumerator();
     }
 
-    private static bool CompareIdentifiers(IReadOnlyList<ValueComparer> valueComparers, object[] left, object[] right)
+    private static bool CompareIdentifiers(IReadOnlyList<Func<object, object, bool>> valueComparers, object[] left, object[] right)
     {
         // Ignoring size check on all for perf as they should be same unless bug in code.
         for (var i = 0; i < left.Length; i++)
         {
-            if (!valueComparers[i].Equals(left[i], right[i]))
+            if (!valueComparers[i](left[i], right[i]))
             {
                 return false;
             }
@@ -160,7 +160,7 @@ private sealed class Enumerator : IEnumerator<IGrouping<TKey, TElement>>
         private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
         private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
         private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-        private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+        private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
         private readonly Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, TElement> _elementSelector;
         private readonly Type _contextType;
         private readonly IDiagnosticsLogger<DbLoggerCategory.Query> _queryLogger;
@@ -344,7 +344,7 @@ private sealed class AsyncEnumerator : IAsyncEnumerator<IGrouping<TKey, TElement
         private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
         private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
         private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-        private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+        private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
         private readonly Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, TElement> _elementSelector;
         private readonly Type _contextType;
         private readonly IDiagnosticsLogger<DbLoggerCategory.Query> _queryLogger;

src/EFCore.Relational/Query/Internal/GroupBySplitQueryingEnumerable.cs

@@ -20,7 +20,7 @@ public class GroupBySplitQueryingEnumerable<TKey, TElement>
     private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
     private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
     private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-    private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+    private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
     private readonly Func<QueryContext, DbDataReader, ResultContext, SplitQueryResultCoordinator, TElement> _elementSelector;
     private readonly Action<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator>? _relatedDataLoaders;
     private readonly Func<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator, Task>? _relatedDataLoadersAsync;
@@ -42,7 +42,7 @@ public GroupBySplitQueryingEnumerable(
         IReadOnlyList<ReaderColumn?>? readerColumns,
         Func<QueryContext, DbDataReader, TKey> keySelector,
         Func<QueryContext, DbDataReader, object[]> keyIdentifier,
-        IReadOnlyList<ValueComparer> keyIdentifierValueComparers,
+        IReadOnlyList<Func<object, object, bool>> keyIdentifierValueComparers,
         Func<QueryContext, DbDataReader, ResultContext, SplitQueryResultCoordinator, TElement> elementSelector,
         Action<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator>? relatedDataLoaders,
         Func<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator, Task>? relatedDataLoadersAsync,
@@ -145,12 +145,12 @@ IEnumerator IEnumerable.GetEnumerator()
             => GetEnumerator();
     }
 
-    private static bool CompareIdentifiers(IReadOnlyList<ValueComparer> valueComparers, object[] left, object[] right)
+    private static bool CompareIdentifiers(IReadOnlyList<Func<object, object, bool>> valueComparers, object[] left, object[] right)
     {
         // Ignoring size check on all for perf as they should be same unless bug in code.
         for (var i = 0; i < left.Length; i++)
         {
-            if (!valueComparers[i].Equals(left[i], right[i]))
+            if (!valueComparers[i](left[i], right[i]))
             {
                 return false;
             }
@@ -166,7 +166,7 @@ private sealed class Enumerator : IEnumerator<IGrouping<TKey, TElement>>
         private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
         private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
         private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-        private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+        private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
         private readonly Func<QueryContext, DbDataReader, ResultContext, SplitQueryResultCoordinator, TElement> _elementSelector;
         private readonly Action<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator>? _relatedDataLoaders;
         private readonly Type _contextType;
@@ -340,7 +340,7 @@ private sealed class AsyncEnumerator : IAsyncEnumerator<IGrouping<TKey, TElement
         private readonly IReadOnlyList<ReaderColumn?>? _readerColumns;
         private readonly Func<QueryContext, DbDataReader, TKey> _keySelector;
         private readonly Func<QueryContext, DbDataReader, object[]> _keyIdentifier;
-        private readonly IReadOnlyList<ValueComparer> _keyIdentifierValueComparers;
+        private readonly IReadOnlyList<Func<object, object, bool>> _keyIdentifierValueComparers;
         private readonly Func<QueryContext, DbDataReader, ResultContext, SplitQueryResultCoordinator, TElement> _elementSelector;
         private readonly Func<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator, Task>? _relatedDataLoaders;
         private readonly Type _contextType;

src/EFCore.Relational/Query/Internal/RelationalProjectionBindingExpressionVisitor.cs

@@ -653,7 +653,13 @@ private ProjectionBindingExpression AddClientProjection(Expression expression, T
         return new ProjectionBindingExpression(_selectExpression, existingIndex, type);
     }
 
-    private static T GetParameterValue<T>(QueryContext queryContext, string parameterName)
+    /// <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 static T GetParameterValue<T>(QueryContext queryContext, string parameterName)
 #pragma warning restore IDE0052 // Remove unread private members
         => (T)queryContext.ParameterValues[parameterName]!;
 

src/EFCore.Relational/Query/Internal/SingleQueryingEnumerable.cs

@@ -6,6 +6,40 @@
 
 namespace Microsoft.EntityFrameworkCore.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 static class SingleQueryingEnumerable
+{
+    /// <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 static SingleQueryingEnumerable<T> Create<T>(
+        RelationalQueryContext relationalQueryContext,
+        RelationalCommandCache relationalCommandCache,
+        IReadOnlyList<ReaderColumn?>? readerColumns,
+        Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, T> shaper,
+        Type contextType,
+        bool standAloneStateManager,
+        bool detailedErrorsEnabled,
+        bool threadSafetyChecksEnabled)
+        => new(
+            relationalQueryContext,
+            relationalCommandCache,
+            readerColumns,
+            shaper,
+            contextType,
+            standAloneStateManager,
+            detailedErrorsEnabled,
+            threadSafetyChecksEnabled);
+}
+
 /// <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

src/EFCore.Relational/Query/Internal/SplitQueryingEnumerable.cs

@@ -6,6 +6,44 @@
 
 namespace Microsoft.EntityFrameworkCore.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 static class SplitQueryingEnumerable
+{
+    /// <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 static SplitQueryingEnumerable<T> Create<T>(
+        RelationalQueryContext relationalQueryContext,
+        RelationalCommandCache relationalCommandCache,
+        IReadOnlyList<ReaderColumn?>? readerColumns,
+        Func<QueryContext, DbDataReader, ResultContext, SplitQueryResultCoordinator, T> shaper,
+        Action<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator>? relatedDataLoaders,
+        Func<QueryContext, IExecutionStrategy, SplitQueryResultCoordinator, Task>? relatedDataLoadersAsync,
+        Type contextType,
+        bool standAloneStateManager,
+        bool detailedErrorsEnabled,
+        bool threadSafetyChecksEnabled)
+        => new(
+            relationalQueryContext,
+            relationalCommandCache,
+            readerColumns,
+            shaper,
+            relatedDataLoaders,
+            relatedDataLoadersAsync,
+            contextType,
+            standAloneStateManager,
+            detailedErrorsEnabled,
+            threadSafetyChecksEnabled);
+}
+
 /// <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