Fix variable coercion for expression-based filter fields

src/HotChocolate/Data/src/Data/Filters/Fields/FilterField.cs

@@ -1,3 +1,4 @@
+using System.Linq.Expressions;
 using System.Reflection;
 using HotChocolate.Configuration;
 using HotChocolate.Internal;
@@ -46,6 +47,10 @@ protected override void OnCompleteField(
         {
             RuntimeType = context.TypeInspector.GetReturnType(Member, ignoreAttributes: true);
         }
+        else if (definition is FilterFieldConfiguration { Expression: LambdaExpression lambda })
+        {
+            RuntimeType = context.TypeInspector.GetType(lambda.ReturnType);
+        }
         else if (base.RuntimeType is { } runtimeType)
         {
             RuntimeType = context.TypeInspector.GetType(runtimeType);

src/HotChocolate/Data/src/Data/Filters/FilterFieldDescriptor.cs

@@ -56,7 +56,6 @@ protected FilterFieldDescriptor(
         if (Configuration.Expression is LambdaExpression lambda)
         {
             Configuration.Type = convention.GetFieldType(lambda.ReturnType);
-            Configuration.RuntimeType = lambda.ReturnType;
         }
     }
 

src/HotChocolate/Data/test/Data.Filters.InMemory.Tests/QueryableFilterVisitorExpressionTests.cs

@@ -78,6 +78,50 @@ public async Task Expression_WithMoreThanOneParameter_ThrowsException()
         ex.Errors.Single().Message.MatchSnapshot();
     }
 
+    [Fact]
+    public async Task Create_CollectionExpression_WithVariables()
+    {
+        // arrange
+        var tester = _cache.CreateSchema<Foo, FooFilterInputType>(s_fooEntities);
+        const string query =
+            """
+            query Test($where: FooFilterInput) {
+              root(where: $where) {
+                name
+                lastName
+              }
+            }
+            """;
+
+        // act
+        var res1 = await tester.ExecuteAsync(
+            OperationRequestBuilder.New()
+                .SetDocument(query)
+                .SetVariableValues(new Dictionary<string, object?>
+                {
+                    { "where", CreateLatestBarFilter("A") }
+                })
+                .Build(),
+            TestContext.Current.CancellationToken);
+
+        var res2 = await tester.ExecuteAsync(
+            OperationRequestBuilder.New()
+                .SetDocument(query)
+                .SetVariableValues(new Dictionary<string, object?>
+                {
+                    { "where", CreateLatestBarFilter("NoMatch") }
+                })
+                .Build(),
+            TestContext.Current.CancellationToken);
+
+        // assert
+        await Snapshot
+            .Create()
+            .Add(res1, "A")
+            .Add(res2, "NoMatch")
+            .MatchAsync(TestContext.Current.CancellationToken);
+    }
+
     [Fact]
     public async Task Create_CollectionLengthExpression()
     {
@@ -112,6 +156,30 @@ await Snapshot
             .MatchAsync(TestContext.Current.CancellationToken);
     }
 
+    private static Dictionary<string, object?> CreateLatestBarFilter(string value)
+        => new()
+        {
+            {
+                "latestBar",
+                new Dictionary<string, object?>
+                {
+                    {
+                        "some",
+                        new Dictionary<string, object?>
+                        {
+                            {
+                                "value",
+                                new Dictionary<string, object?>
+                                {
+                                    { "eq", value }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        };
+
     public class Foo
     {
         public int Id { get; set; }
@@ -136,6 +204,12 @@ protected override void Configure(IFilterInputTypeDescriptor<Foo> descriptor)
         {
             descriptor.Field(x => x.Name + " " + x.LastName).Name("displayName");
             descriptor.Field(x => x.Bars!.Count).Name("barLength");
+            descriptor
+                .Field(x => x.Bars!.OrderByDescending(b => b.Id).Take(1))
+                .Name("latestBar")
+                .Type<ListFilterInputType<BarFilterInputType>>();
         }
     }
+
+    public class BarFilterInputType : FilterInputType<Bar>;
 }

src/HotChocolate/Data/test/Data.Filters.InMemory.Tests/__snapshots__/QueryableFilterVisitorExpressionTests.Create_CollectionExpression_WithVariables.snap

@@ -0,0 +1,22 @@
+A
+---------------
+{
+  "data": {
+    "root": [
+      {
+        "name": "Foo",
+        "lastName": "Galoo"
+      }
+    ]
+  }
+}
+---------------
+
+NoMatch
+---------------
+{
+  "data": {
+    "root": []
+  }
+}
+---------------