Fix MemberExpression funcletization

src/EFCore/Query/Internal/ExpressionTreeFuncletizer.cs

@@ -738,10 +738,13 @@ protected override Expression VisitLambda<T>(Expression<T> lambda)
     protected override Expression VisitMember(MemberExpression member)
     {
         // Static member access - notably required for EF.Functions, but also for various translations (DateTime.Now).
+        // Note that this is treated as a captured variable (so will be parameterized), unless the captured variable is init-only.
         if (member.Expression is null)
         {
             _state = IsGenerallyEvaluatable(member)
-                ? State.CreateEvaluatable(typeof(MemberExpression), containsCapturedVariable: false)
+                ? State.CreateEvaluatable(
+                    typeof(MemberExpression),
+                    containsCapturedVariable: member.Member is not FieldInfo { IsInitOnly: true })
                 : State.NoEvaluatability;
             return member;
         }
@@ -766,7 +769,8 @@ protected override Expression VisitMember(MemberExpression member)
 
             if (IsGenerallyEvaluatable(member))
             {
-                _state = State.CreateEvaluatable(typeof(MemberExpression), _state.ContainsCapturedVariable);
+                // Note that any evaluatable MemberExpression is treated as a captured variable.
+                _state = State.CreateEvaluatable(typeof(MemberExpression), containsCapturedVariable: true);
                 return member.Update(expression);
             }
 
@@ -1718,9 +1722,7 @@ private static StateType CombineStateTypes(StateType stateType1, StateType state
                 // We don't evaluate as constant if we're not inside a lambda, i.e. in a top-level operator. This is to make sure that
                 // non-lambda arguments to e.g. Skip/Take are parameterized rather than evaluated as constant, since that would produce
                 // different SQLs for each value.
-                || !_inLambda
-                || (evaluatableRoot is MemberExpression member
-                    && (member.Expression is not null || member.Member is not FieldInfo { IsInitOnly: true })));
+                || !_inLambda);
 
         // We have some cases where a node is evaluatable, but only as part of a larger subtree, and should not be evaluated as a tree root.
         // For these cases, the node's state has a notEvaluatableAsRootHandler lambda, which we can invoke to make evaluate the node's

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

@@ -4714,6 +4714,20 @@ FROM root c
 """);
     }
 
+    public override async Task Static_member_access_gets_parameterized_within_larger_evaluatable(bool async)
+    {
+        await base.Static_member_access_gets_parameterized_within_larger_evaluatable(async);
+
+        AssertSql(
+            """
+@__p_0='ALFKI'
+
+SELECT c
+FROM root c
+WHERE ((c["Discriminator"] = "Customer") AND (c["CustomerID"] = @__p_0))
+""");
+    }
+
     private void AssertSql(params string[] expected)
         => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
 

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

@@ -5776,4 +5776,14 @@ private class MyCustomerDetails
         public string CustomerId { get; set; }
         public string City { get; set; }
     }
+
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Static_member_access_gets_parameterized_within_larger_evaluatable(bool async)
+        => AssertQuery(
+            async,
+            ss => ss.Set<Customer>().Where(c => c.CustomerID == StaticProperty + "KI"));
+
+    private static string StaticProperty
+        => "ALF";
 }

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

@@ -7449,6 +7449,20 @@ public override async Task Compiler_generated_local_closure_produces_valid_param
         //AssertSql("");
     }
 
+    public override async Task Static_member_access_gets_parameterized_within_larger_evaluatable(bool async)
+    {
+        await base.Static_member_access_gets_parameterized_within_larger_evaluatable(async);
+
+        AssertSql(
+            """
+@__p_0='ALFKI' (Size = 5) (DbType = StringFixedLength)
+
+SELECT [c].[CustomerID], [c].[Address], [c].[City], [c].[CompanyName], [c].[ContactName], [c].[ContactTitle], [c].[Country], [c].[Fax], [c].[Phone], [c].[PostalCode], [c].[Region]
+FROM [Customers] AS [c]
+WHERE [c].[CustomerID] = @__p_0
+""");
+    }
+
     private void AssertSql(params string[] expected)
         => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);