Query: Assign proper type to collection result expression (part 2)

This improves the fix made in #27134

In earlier PR we converted `IQueryable<T>` to `IEnumerable<T>` becaused we converted enumerable to queryable during preprocessing phase and types aligned in later phase since we create a list (which does implement `IEnumerable<T>`). Though this implementing behavior doesn't work when returning a single result of enumerable during async which wraps collection type inside Task.
The better fix is to assign `List<T>` as type since we are eventually creating a list.
In case of single result, the single result operator has generic type which will introduce convert node into it automatically which will match types for async tasks.

Resolves #27600

src/EFCore.Analyzers/InternalUsageDiagnosticAnalyzer.cs

@@ -27,7 +27,7 @@ public const string MessageFormat
         private static readonly int EFLen = "EntityFrameworkCore".Length;
 
         private static readonly DiagnosticDescriptor _descriptor
-            = new(
+            = new DiagnosticDescriptor(
                 Id,
                 title: DefaultTitle,
                 messageFormat: MessageFormat,

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

@@ -198,14 +198,27 @@ public virtual Expression Translate(SelectExpression selectExpression, Expressio
 
                                     _clientProjections!.Add(subquery);
                                     var type = expression.Type;
-                                    if (!(AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue27105", out var enabled) && enabled))
+
+                                    if (!(AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue27105", out var enabled27105) && enabled27105))
                                     {
-                                        if (type.IsGenericType
-                                            && type.GetGenericTypeDefinition() == typeof(IQueryable<>))
+                                        if (!(AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue27600", out var enabled27600) && enabled27600))
+                                        {
+                                            if (type.IsGenericType
+                                                && type.GetGenericTypeDefinition() == typeof(IQueryable<>))
+                                            {
+                                                type = typeof(List<>).MakeGenericType(type.GetSequenceType());
+                                            }
+                                        }
+                                        else
                                         {
-                                            type = typeof(IEnumerable<>).MakeGenericType(type.GetSequenceType());
+                                            if (type.IsGenericType
+                                                && type.GetGenericTypeDefinition() == typeof(IQueryable<>))
+                                            {
+                                                type = typeof(IEnumerable<>).MakeGenericType(type.GetSequenceType());
+                                            }
                                         }
                                     }
+
                                     var projectionBindingExpression = new ProjectionBindingExpression(
                                         _selectExpression, _clientProjections.Count - 1, type);
                                     return subquery.ResultCardinality == ResultCardinality.Enumerable

test/EFCore.Cosmos.FunctionalTests/Query/NorthwindSelectQueryCosmosTest.cs

@@ -1332,6 +1332,12 @@ public override Task List_of_list_of_anonymous_type(bool async)
             return base.List_of_list_of_anonymous_type(async);
         }
 
+        [ConditionalTheory(Skip = "Cross collection join Issue#17246")]
+        public override Task List_from_result_of_single_result(bool async)
+        {
+            return base.List_from_result_of_single_result(async);
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
 

test/EFCore.Specification.Tests/Query/NorthwindSelectQueryTestBase.cs

@@ -2472,5 +2472,17 @@ public virtual Task List_of_list_of_anonymous_type(bool async)
                         elementAsserter: (ee, aa) => AssertCollection(ee, aa, elementSorter: i => (i.OrderID, i.ProductID)));
                 });
         }
+
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual Task List_from_result_of_single_result(bool async)
+        {
+            return AssertFirstOrDefault(
+                async,
+                ss => ss.Set<Customer>()
+                        .OrderBy(c => c.CustomerID)
+                        .Select(c => c.Orders.Select(e => e.OrderID)),
+                asserter: (e, a) => AssertCollection(e, a, elementSorter: e => e, elementAsserter: (ee, aa) => AssertEqual(ee, aa)));
+        }
     }
 }

test/EFCore.SqlServer.FunctionalTests/Query/NorthwindSelectQuerySqlServerTest.cs

@@ -1891,6 +1891,21 @@ WHERE [c].[CustomerID] LIKE N'F%'
 ORDER BY [c].[CustomerID], [t].[OrderID], [t].[OrderID0]");
         }
 
+        public override async Task List_from_result_of_single_result(bool async)
+        {
+            await base.List_from_result_of_single_result(async);
+
+            AssertSql(
+                @"SELECT [t].[CustomerID], [o].[OrderID]
+FROM (
+    SELECT TOP(1) [c].[CustomerID]
+    FROM [Customers] AS [c]
+    ORDER BY [c].[CustomerID]
+) AS [t]
+LEFT JOIN [Orders] AS [o] ON [t].[CustomerID] = [o].[CustomerID]
+ORDER BY [t].[CustomerID]");
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);