Take into account Contains item visitation in SqlNullabilityProcessor

src/EFCore.Relational/Query/SqlNullabilityProcessor.cs

@@ -649,6 +649,7 @@ protected virtual SqlExpression VisitIn(InExpression inExpression, bool allowOpt
         // SQL IN returns null when the item is null, and when the values (or subquery projection) contains NULL and no match was made.
 
         var item = Visit(inExpression.Item, out var itemNullable);
+        inExpression = inExpression.Update(item, inExpression.Subquery, inExpression.Values, inExpression.ValuesParameter);
 
         if (inExpression.Subquery != null)
         {

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

@@ -807,6 +807,20 @@ public virtual Task Project_primitive_collections_element(bool async)
             },
             assertOrder: true);
 
+    [ConditionalTheory] // #32208
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Nested_contains_with_Lists_and_no_inferred_type_mapping(bool async)
+    {
+        var ints = new List<int> { 1, 2, 3 };
+        var strings = new List<string> { "one", "two", "three" };
+
+        // Note that in this query, the outer Contains really has no type mapping, neither for its source (collection parameter), nor
+        // for its item (the conditional expression returns constants). The default type mapping must be applied.
+        return AssertQuery(
+            async,
+            ss => ss.Set<PrimitiveCollectionsEntity>().Where(e => strings.Contains(ints.Contains(e.Int) ? "one" : "two")));
+    }
+
     public abstract class PrimitiveCollectionsQueryFixtureBase : SharedStoreFixtureBase<PrimitiveCollectionsContext>, IQueryFixtureBase
     {
         private PrimitiveArrayData? _expectedData;

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

@@ -610,6 +610,21 @@ ORDER BY [p].[Id]
 """);
     }
 
+    public override async Task Nested_contains_with_Lists_and_no_inferred_type_mapping(bool async)
+    {
+        await base.Nested_contains_with_Lists_and_no_inferred_type_mapping(async);
+
+        AssertSql(
+            """
+SELECT [p].[Id], [p].[Bool], [p].[Bools], [p].[DateTime], [p].[DateTimes], [p].[Enum], [p].[Enums], [p].[Int], [p].[Ints], [p].[NullableInt], [p].[NullableInts], [p].[NullableString], [p].[NullableStrings], [p].[String], [p].[Strings]
+FROM [PrimitiveCollectionsEntity] AS [p]
+WHERE CASE
+    WHEN [p].[Int] IN (1, 2, 3) THEN N'one'
+    ELSE N'two'
+END IN (N'one', N'two', N'three')
+""");
+    }
+
     [ConditionalFact]
     public virtual void Check_all_tests_overridden()
         => TestHelpers.AssertAllMethodsOverridden(GetType());

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

@@ -1227,6 +1227,26 @@ ORDER BY [p].[Id]
 """);
     }
 
+    public override async Task Nested_contains_with_Lists_and_no_inferred_type_mapping(bool async)
+    {
+        await base.Nested_contains_with_Lists_and_no_inferred_type_mapping(async);
+
+        AssertSql(
+            """
+@__strings_0='["one","two","three"]' (Size = 4000)
+
+SELECT [p].[Id], [p].[Bool], [p].[Bools], [p].[DateTime], [p].[DateTimes], [p].[Enum], [p].[Enums], [p].[Int], [p].[Ints], [p].[NullableInt], [p].[NullableInts], [p].[NullableString], [p].[NullableStrings], [p].[String], [p].[Strings]
+FROM [PrimitiveCollectionsEntity] AS [p]
+WHERE CASE
+    WHEN [p].[Int] IN (1, 2, 3) THEN N'one'
+    ELSE N'two'
+END IN (
+    SELECT [s].[value]
+    FROM OPENJSON(@__strings_0) WITH ([value] nvarchar(max) '$') AS [s]
+)
+""");
+    }
+
     [ConditionalFact]
     public virtual void Check_all_tests_overridden()
         => TestHelpers.AssertAllMethodsOverridden(GetType());

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

@@ -336,7 +336,7 @@ public override void Scalar_Function_with_nested_InExpression_translation()
 SELECT [c].[Id], [c].[FirstName], [c].[LastName]
 FROM [Customers] AS [c]
 WHERE CASE
-    WHEN SUBSTRING([c].[FirstName], 0 + 1, 1) IN (N'A', N'B', N'C') THEN CAST(1 AS bit)
+    WHEN SUBSTRING([c].[FirstName], 0 + 1, 1) IN (N'A', N'B', N'C') AND SUBSTRING([c].[FirstName], 0 + 1, 1) IS NOT NULL THEN CAST(1 AS bit)
     ELSE CAST(0 AS bit)
 END IN (CAST(1 AS bit), CAST(0 AS bit))
 """);

test/EFCore.Sqlite.FunctionalTests/Query/PrimitiveCollectionsQuerySqliteTest.cs

@@ -1109,6 +1109,26 @@ public override async Task Project_empty_collection_of_nullables_and_collection_
             (await Assert.ThrowsAsync<InvalidOperationException>(
                 () => base.Project_empty_collection_of_nullables_and_collection_only_containing_nulls(async))).Message);
 
+    public override async Task Nested_contains_with_Lists_and_no_inferred_type_mapping(bool async)
+    {
+        await base.Nested_contains_with_Lists_and_no_inferred_type_mapping(async);
+
+        AssertSql(
+            """
+@__strings_0='["one","two","three"]' (Size = 21)
+
+SELECT "p"."Id", "p"."Bool", "p"."Bools", "p"."DateTime", "p"."DateTimes", "p"."Enum", "p"."Enums", "p"."Int", "p"."Ints", "p"."NullableInt", "p"."NullableInts", "p"."NullableString", "p"."NullableStrings", "p"."String", "p"."Strings"
+FROM "PrimitiveCollectionsEntity" AS "p"
+WHERE CASE
+    WHEN "p"."Int" IN (1, 2, 3) THEN 'one'
+    ELSE 'two'
+END IN (
+    SELECT "s"."value"
+    FROM json_each(@__strings_0) AS "s"
+)
+""");
+    }
+
     [ConditionalFact]
     public virtual void Check_all_tests_overridden()
         => TestHelpers.AssertAllMethodsOverridden(GetType());