diff --git a/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.c b/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.c
new file mode 100644
index 0000000..48c16f6
--- /dev/null
+++ b/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.c
@@ -0,0 +1,105 @@
+/**
+ * TopLevel.c
+ * This file has been autogenerated using quicktype https://github.com/quicktype/quicktype - DO NOT EDIT
+ */
+
+#include "TopLevel.h"
+
+struct TopLevel * cJSON_ParseTopLevel(const char * s) {
+    struct TopLevel * x = NULL;
+    if (NULL != s) {
+        cJSON * j = cJSON_Parse(s);
+        if (NULL != j) {
+            x = cJSON_GetTopLevelValue(j);
+            cJSON_Delete(j);
+        }
+    }
+    return x;
+}
+
+struct TopLevel * cJSON_GetTopLevelValue(const cJSON * j) {
+    struct TopLevel * x = NULL;
+    if (NULL != j) {
+        if (NULL != (x = cJSON_malloc(sizeof(struct TopLevel)))) {
+            memset(x, 0, sizeof(struct TopLevel));
+            if (!cJSON_HasObjectItem(j, "hashCode")) { cJSON_DeleteTopLevel(x); return NULL; }
+            if (cJSON_HasObjectItem(j, "hashCode")) {
+                if (!cJSON_IsString(cJSON_GetObjectItemCaseSensitive(j, "hashCode"))) { cJSON_DeleteTopLevel(x); return NULL; }
+                x->hash_code = strdup(cJSON_GetStringValue(cJSON_GetObjectItemCaseSensitive(j, "hashCode")));
+            }
+            else {
+                if (NULL != (x->hash_code = cJSON_malloc(sizeof(char)))) {
+                    x->hash_code[0] = '\0';
+                }
+            }
+            if (!cJSON_HasObjectItem(j, "noSuchMethod")) { cJSON_DeleteTopLevel(x); return NULL; }
+            if (cJSON_HasObjectItem(j, "noSuchMethod")) {
+                if (!cJSON_IsString(cJSON_GetObjectItemCaseSensitive(j, "noSuchMethod"))) { cJSON_DeleteTopLevel(x); return NULL; }
+                x->no_such_method = strdup(cJSON_GetStringValue(cJSON_GetObjectItemCaseSensitive(j, "noSuchMethod")));
+            }
+            else {
+                if (NULL != (x->no_such_method = cJSON_malloc(sizeof(char)))) {
+                    x->no_such_method[0] = '\0';
+                }
+            }
+            if (!cJSON_HasObjectItem(j, "runtimeType")) { cJSON_DeleteTopLevel(x); return NULL; }
+            if (cJSON_HasObjectItem(j, "runtimeType")) {
+                if (!quicktype_cJSON_IsInteger(cJSON_GetObjectItemCaseSensitive(j, "runtimeType"))) { cJSON_DeleteTopLevel(x); return NULL; }
+                x->runtime_type = cJSON_GetNumberValue(cJSON_GetObjectItemCaseSensitive(j, "runtimeType"));
+            }
+            if (!cJSON_HasObjectItem(j, "toString")) { cJSON_DeleteTopLevel(x); return NULL; }
+            if (cJSON_HasObjectItem(j, "toString")) {
+                if (!cJSON_IsBool(cJSON_GetObjectItemCaseSensitive(j, "toString"))) { cJSON_DeleteTopLevel(x); return NULL; }
+                x->to_string = cJSON_IsTrue(cJSON_GetObjectItemCaseSensitive(j, "toString"));
+            }
+        }
+    }
+    return x;
+}
+
+cJSON * cJSON_CreateTopLevel(const struct TopLevel * x) {
+    cJSON * j = NULL;
+    if (NULL != x) {
+        if (NULL != (j = cJSON_CreateObject())) {
+            if (NULL != x->hash_code) {
+                cJSON_AddStringToObject(j, "hashCode", x->hash_code);
+            }
+            else {
+                cJSON_AddStringToObject(j, "hashCode", "");
+            }
+            if (NULL != x->no_such_method) {
+                cJSON_AddStringToObject(j, "noSuchMethod", x->no_such_method);
+            }
+            else {
+                cJSON_AddStringToObject(j, "noSuchMethod", "");
+            }
+            cJSON_AddNumberToObject(j, "runtimeType", x->runtime_type);
+            cJSON_AddBoolToObject(j, "toString", x->to_string);
+        }
+    }
+    return j;
+}
+
+char * cJSON_PrintTopLevel(const struct TopLevel * x) {
+    char * s = NULL;
+    if (NULL != x) {
+        cJSON * j = cJSON_CreateTopLevel(x);
+        if (NULL != j) {
+            s = cJSON_Print(j);
+            cJSON_Delete(j);
+        }
+    }
+    return s;
+}
+
+void cJSON_DeleteTopLevel(struct TopLevel * x) {
+    if (NULL != x) {
+        if (NULL != x->hash_code) {
+            cJSON_free(x->hash_code);
+        }
+        if (NULL != x->no_such_method) {
+            cJSON_free(x->no_such_method);
+        }
+        cJSON_free(x);
+    }
+}
diff --git a/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.h b/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.h
new file mode 100644
index 0000000..074019a
--- /dev/null
+++ b/head/cjson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.h
@@ -0,0 +1,58 @@
+/**
+ * TopLevel.h
+ * This file has been autogenerated using quicktype https://github.com/quicktype/quicktype - DO NOT EDIT
+ * This file depends of https://github.com/DaveGamble/cJSON, https://github.com/joelguittet/c-list and https://github.com/joelguittet/c-hashtable
+ * To parse json data from json string use the following: struct <type> * data = cJSON_Parse<type>(<string>);
+ * To get json data from cJSON object use the following: struct <type> * data = cJSON_Get<type>Value(<cjson>);
+ * To get cJSON object from json data use the following: cJSON * cjson = cJSON_Create<type>(<data>);
+ * To print json string from json data use the following: char * string = cJSON_Print<type>(<data>);
+ * To delete json data use the following: cJSON_Delete<type>(<data>);
+ */
+
+#ifndef __TOPLEVEL_H__
+#define __TOPLEVEL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <regex.h>
+#include <cJSON.h>
+#include <hashtable.h>
+#include <list.h>
+
+#define quicktype_cJSON_Duplicate(j) cJSON_Duplicate(j, true)
+#define cJSON_Integer (1 << 18)
+#define quicktype_cJSON_IsInteger(j) (cJSON_IsNumber(j) && (j)->valuedouble == (int64_t)(j)->valuedouble)
+#ifndef cJSON_Bool
+#define cJSON_Bool (cJSON_True | cJSON_False)
+#endif
+#ifndef cJSON_Map
+#define cJSON_Map (1 << 16)
+#endif
+#ifndef cJSON_Enum
+#define cJSON_Enum (1 << 17)
+#endif
+
+struct TopLevel {
+    char * hash_code;
+    char * no_such_method;
+    int64_t runtime_type;
+    bool to_string;
+};
+
+struct TopLevel * cJSON_ParseTopLevel(const char * s);
+struct TopLevel * cJSON_GetTopLevelValue(const cJSON * j);
+cJSON * cJSON_CreateTopLevel(const struct TopLevel * x);
+char * cJSON_PrintTopLevel(const struct TopLevel * x);
+void cJSON_DeleteTopLevel(struct TopLevel * x);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __TOPLEVEL_H__ */
diff --git a/head/cplusplus/test/inputs/json/samples/dart-object-members.json/default/quicktype.hpp b/head/cplusplus/test/inputs/json/samples/dart-object-members.json/default/quicktype.hpp
new file mode 100644
index 0000000..0df367b
--- /dev/null
+++ b/head/cplusplus/test/inputs/json/samples/dart-object-members.json/default/quicktype.hpp
@@ -0,0 +1,84 @@
+//  To parse this JSON data, first install
+//
+//      json.hpp  https://github.com/nlohmann/json
+//
+//  Then include this file, and then do
+//
+//     TopLevel data = nlohmann::json::parse(jsonString);
+
+#pragma once
+
+#include "json.hpp"
+
+#include <optional>
+#include <stdexcept>
+#include <regex>
+
+namespace quicktype {
+    using nlohmann::json;
+
+    #ifndef NLOHMANN_UNTYPED_quicktype_HELPER
+    #define NLOHMANN_UNTYPED_quicktype_HELPER
+    inline json get_untyped(const json & j, const char * property) {
+        if (j.find(property) != j.end()) {
+            return j.at(property).get<json>();
+        }
+        return json();
+    }
+
+    inline json get_untyped(const json & j, std::string property) {
+        return get_untyped(j, property.data());
+    }
+    #endif
+
+    class TopLevel {
+        public:
+        TopLevel() = default;
+        virtual ~TopLevel() = default;
+
+        private:
+        std::string hash_code;
+        std::string no_such_method;
+        int64_t runtime_type;
+        bool to_string;
+
+        public:
+        const std::string & get_hash_code() const { return hash_code; }
+        std::string & get_mutable_hash_code() { return hash_code; }
+        void set_hash_code(const std::string & value) { this->hash_code = value; }
+
+        const std::string & get_no_such_method() const { return no_such_method; }
+        std::string & get_mutable_no_such_method() { return no_such_method; }
+        void set_no_such_method(const std::string & value) { this->no_such_method = value; }
+
+        const int64_t & get_runtime_type() const { return runtime_type; }
+        int64_t & get_mutable_runtime_type() { return runtime_type; }
+        void set_runtime_type(const int64_t & value) { this->runtime_type = value; }
+
+        const bool & get_to_string() const { return to_string; }
+        bool & get_mutable_to_string() { return to_string; }
+        void set_to_string(const bool & value) { this->to_string = value; }
+    };
+}
+
+namespace quicktype {
+    void from_json(const json & j, TopLevel & x);
+    void to_json(json & j, const TopLevel & x);
+
+    inline void from_json(const json & j, TopLevel& x) {
+        if (!j.is_object()) throw std::runtime_error("Expected object");
+        x.set_hash_code(j.at("hashCode").get<std::string>());
+        x.set_no_such_method(j.at("noSuchMethod").get<std::string>());
+        if (j.find("runtimeType") != j.end() && !j.at("runtimeType").is_number_integer()) throw std::runtime_error("Expected integer");
+        x.set_runtime_type(j.at("runtimeType").get<int64_t>());
+        x.set_to_string(j.at("toString").get<bool>());
+    }
+
+    inline void to_json(json & j, const TopLevel & x) {
+        j = json::object();
+        j["hashCode"] = x.get_hash_code();
+        j["noSuchMethod"] = x.get_no_such_method();
+        j["runtimeType"] = x.get_runtime_type();
+        j["toString"] = x.get_to_string();
+    }
+}
diff --git a/head/crystal/test/inputs/json/samples/dart-object-members.json/default/TopLevel.cr b/head/crystal/test/inputs/json/samples/dart-object-members.json/default/TopLevel.cr
new file mode 100644
index 0000000..70fbd39
--- /dev/null
+++ b/head/crystal/test/inputs/json/samples/dart-object-members.json/default/TopLevel.cr
@@ -0,0 +1,17 @@
+require "json"
+
+class TopLevel
+  include JSON::Serializable
+
+  @[JSON::Field(key: "hashCode")]
+  property hash_code : String
+
+  @[JSON::Field(key: "noSuchMethod")]
+  property no_such_method : String
+
+  @[JSON::Field(key: "runtimeType")]
+  property runtime_type : Int64
+
+  @[JSON::Field(key: "toString")]
+  property to_string : Bool
+end
diff --git a/head/csharp/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs b/head/csharp/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
new file mode 100644
index 0000000..c5d6778
--- /dev/null
+++ b/head/csharp/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
@@ -0,0 +1,70 @@
+// <auto-generated />
+//
+// To parse this JSON data, add NuGet 'Newtonsoft.Json' then do:
+//
+//    using QuickType;
+//
+//    var topLevel = TopLevel.FromJson(jsonString);
+#nullable enable
+#pragma warning disable CS8618
+#pragma warning disable CS8601
+#pragma warning disable CS8602
+#pragma warning disable CS8603
+#pragma warning disable CS8604
+#pragma warning disable CS8625
+#pragma warning disable CS8765
+
+namespace QuickType
+{
+    using System;
+    using System.Collections.Generic;
+
+    using System.Globalization;
+    using Newtonsoft.Json;
+    using Newtonsoft.Json.Converters;
+
+    public partial class TopLevel
+    {
+        [JsonProperty("hashCode", Required = Required.Always)]
+        public string HashCode { get; set; }
+
+        [JsonProperty("noSuchMethod", Required = Required.Always)]
+        public string NoSuchMethod { get; set; }
+
+        [JsonProperty("runtimeType", Required = Required.Always)]
+        public long RuntimeType { get; set; }
+
+        [JsonProperty("toString", Required = Required.Always)]
+        public bool TopLevelToString { get; set; }
+    }
+
+    public partial class TopLevel
+    {
+        public static TopLevel FromJson(string json) => JsonConvert.DeserializeObject<TopLevel>(json, QuickType.Converter.Settings);
+    }
+
+    public static partial class Serialize
+    {
+        public static string ToJson(this TopLevel self) => JsonConvert.SerializeObject(self, QuickType.Converter.Settings);
+    }
+
+    internal static partial class Converter
+    {
+        public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
+        {
+            MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
+            DateParseHandling = DateParseHandling.None,
+            Converters =
+            {
+                new IsoDateTimeConverter { DateTimeStyles = DateTimeStyles.AssumeUniversal }
+            },
+        };
+    }
+}
+#pragma warning restore CS8618
+#pragma warning restore CS8601
+#pragma warning restore CS8602
+#pragma warning restore CS8603
+#pragma warning restore CS8604
+#pragma warning restore CS8625
+#pragma warning restore CS8765
diff --git a/head/csharp-SystemTextJson/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs b/head/csharp-SystemTextJson/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
new file mode 100644
index 0000000..48e6105
--- /dev/null
+++ b/head/csharp-SystemTextJson/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
@@ -0,0 +1,178 @@
+// <auto-generated />
+//
+// To parse this JSON data, add NuGet 'System.Text.Json' then do:
+//
+//    using QuickType;
+//
+//    var topLevel = TopLevel.FromJson(jsonString);
+#nullable enable
+#pragma warning disable CS8618
+#pragma warning disable CS8601
+#pragma warning disable CS8602
+#pragma warning disable CS8603
+
+namespace QuickType
+{
+    using System;
+    using System.Collections.Generic;
+
+    using System.Text.Json;
+    using System.Text.Json.Serialization;
+    using System.Globalization;
+
+    public partial class TopLevel
+    {
+        [JsonRequired]
+        [JsonPropertyName("hashCode")]
+        public string HashCode { get; set; }
+
+        [JsonRequired]
+        [JsonPropertyName("noSuchMethod")]
+        public string NoSuchMethod { get; set; }
+
+        [JsonRequired]
+        [JsonPropertyName("runtimeType")]
+        public long RuntimeType { get; set; }
+
+        [JsonRequired]
+        [JsonPropertyName("toString")]
+        public bool TopLevelToString { get; set; }
+    }
+
+    public partial class TopLevel
+    {
+        public static TopLevel FromJson(string json) => global::System.Text.Json.JsonSerializer.Deserialize<TopLevel>(json, QuickType.Converter.Settings);
+    }
+
+    public static partial class Serialize
+    {
+        public static string ToJson(this TopLevel self) => JsonSerializer.Serialize(self, QuickType.Converter.Settings);
+    }
+
+    internal static partial class Converter
+    {
+        public static readonly JsonSerializerOptions Settings = new(JsonSerializerDefaults.General)
+        {
+            Converters =
+            {
+                new DateOnlyConverter(),
+                new TimeOnlyConverter(),
+                IsoDateTimeOffsetConverter.Singleton
+            },
+        };
+    }
+    
+    public class DateOnlyConverter : JsonConverter<DateOnly>
+    {
+        private readonly string serializationFormat;
+        public DateOnlyConverter() : this(null) { }
+
+        public DateOnlyConverter(string? serializationFormat)
+        {
+                this.serializationFormat = serializationFormat ?? "yyyy-MM-dd";
+        }
+
+        public override DateOnly Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+                var value = reader.GetString();
+                return DateOnly.Parse(value!);
+        }
+
+        public override void Write(Utf8JsonWriter writer, DateOnly value, JsonSerializerOptions options)
+                => writer.WriteStringValue(value.ToString(serializationFormat));
+    }
+
+    public class TimeOnlyConverter : JsonConverter<TimeOnly>
+    {
+        private readonly string serializationFormat;
+
+        public TimeOnlyConverter() : this(null) { }
+
+        public TimeOnlyConverter(string? serializationFormat)
+        {
+                this.serializationFormat = serializationFormat ?? "HH:mm:ss.fff";
+        }
+
+        public override TimeOnly Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+                var value = reader.GetString();
+                return TimeOnly.Parse(value!);
+        }
+
+        public override void Write(Utf8JsonWriter writer, TimeOnly value, JsonSerializerOptions options)
+                => writer.WriteStringValue(value.ToString(serializationFormat));
+    }
+
+    internal class IsoDateTimeOffsetConverter : JsonConverter<DateTimeOffset>
+    {
+        public override bool CanConvert(Type t) => t == typeof(DateTimeOffset);
+
+        private const string DefaultDateTimeFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss.FFFFFFFK";
+
+        private DateTimeStyles _dateTimeStyles = DateTimeStyles.RoundtripKind;
+        private string? _dateTimeFormat;
+        private CultureInfo? _culture;
+
+        public DateTimeStyles DateTimeStyles
+        {
+                get => _dateTimeStyles;
+                set => _dateTimeStyles = value;
+        }
+
+        public string? DateTimeFormat
+        {
+                get => _dateTimeFormat ?? string.Empty;
+                set => _dateTimeFormat = (string.IsNullOrEmpty(value)) ? null : value;
+        }
+
+        public CultureInfo Culture
+        {
+                get => _culture ?? CultureInfo.CurrentCulture;
+                set => _culture = value;
+        }
+
+        public override void Write(Utf8JsonWriter writer, DateTimeOffset value, JsonSerializerOptions options)
+        {
+                string text;
+
+
+                if ((_dateTimeStyles & DateTimeStyles.AdjustToUniversal) == DateTimeStyles.AdjustToUniversal
+                        || (_dateTimeStyles & DateTimeStyles.AssumeUniversal) == DateTimeStyles.AssumeUniversal)
+                {
+                        value = value.ToUniversalTime();
+                }
+
+                text = value.ToString(_dateTimeFormat ?? DefaultDateTimeFormat, Culture);
+
+                writer.WriteStringValue(text);
+        }
+
+        public override DateTimeOffset Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+                string? dateText = reader.GetString();
+
+                if (string.IsNullOrEmpty(dateText) == false)
+                {
+                        if (!string.IsNullOrEmpty(_dateTimeFormat))
+                        {
+                                return DateTimeOffset.ParseExact(dateText, _dateTimeFormat, Culture, _dateTimeStyles);
+                        }
+                        else
+                        {
+                                return DateTimeOffset.Parse(dateText, Culture, _dateTimeStyles);
+                        }
+                }
+                else
+                {
+                        return default(DateTimeOffset);
+                }
+        }
+
+
+        public static readonly IsoDateTimeOffsetConverter Singleton = new IsoDateTimeOffsetConverter();
+    }
+}
+#pragma warning restore CS8618
+#pragma warning restore CS8601
+#pragma warning restore CS8602
+#pragma warning restore CS8603
diff --git a/head/csharp-records/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs b/head/csharp-records/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
new file mode 100644
index 0000000..e4db42b
--- /dev/null
+++ b/head/csharp-records/test/inputs/json/samples/dart-object-members.json/default/QuickType.cs
@@ -0,0 +1,70 @@
+// <auto-generated />
+//
+// To parse this JSON data, add NuGet 'Newtonsoft.Json' then do:
+//
+//    using QuickType;
+//
+//    var topLevel = TopLevel.FromJson(jsonString);
+#nullable enable
+#pragma warning disable CS8618
+#pragma warning disable CS8601
+#pragma warning disable CS8602
+#pragma warning disable CS8603
+#pragma warning disable CS8604
+#pragma warning disable CS8625
+#pragma warning disable CS8765
+
+namespace QuickType
+{
+    using System;
+    using System.Collections.Generic;
+
+    using System.Globalization;
+    using Newtonsoft.Json;
+    using Newtonsoft.Json.Converters;
+
+    public partial record TopLevel
+    {
+        [JsonProperty("hashCode", Required = Required.Always)]
+        public string HashCode { get; set; }
+
+        [JsonProperty("noSuchMethod", Required = Required.Always)]
+        public string NoSuchMethod { get; set; }
+
+        [JsonProperty("runtimeType", Required = Required.Always)]
+        public long RuntimeType { get; set; }
+
+        [JsonProperty("toString", Required = Required.Always)]
+        public bool TopLevelToString { get; set; }
+    }
+
+    public partial record TopLevel
+    {
+        public static TopLevel FromJson(string json) => JsonConvert.DeserializeObject<TopLevel>(json, QuickType.Converter.Settings);
+    }
+
+    public static partial class Serialize
+    {
+        public static string ToJson(this TopLevel self) => JsonConvert.SerializeObject(self, QuickType.Converter.Settings);
+    }
+
+    internal static partial class Converter
+    {
+        public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
+        {
+            MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
+            DateParseHandling = DateParseHandling.None,
+            Converters =
+            {
+                new IsoDateTimeConverter { DateTimeStyles = DateTimeStyles.AssumeUniversal }
+            },
+        };
+    }
+}
+#pragma warning restore CS8618
+#pragma warning restore CS8601
+#pragma warning restore CS8602
+#pragma warning restore CS8603
+#pragma warning restore CS8604
+#pragma warning restore CS8625
+#pragma warning restore CS8765
diff --git a/head/dart/test/inputs/json/samples/dart-object-members.json/default/TopLevel.dart b/head/dart/test/inputs/json/samples/dart-object-members.json/default/TopLevel.dart
new file mode 100644
index 0000000..9d7c58f
--- /dev/null
+++ b/head/dart/test/inputs/json/samples/dart-object-members.json/default/TopLevel.dart
@@ -0,0 +1,37 @@
+// To parse this JSON data, do
+//
+//     final topLevel = topLevelFromJson(jsonString);
+
+import 'dart:convert';
+
+TopLevel topLevelFromJson(String str) => TopLevel.fromJson(json.decode(str));
+
+String topLevelToJson(TopLevel data) => json.encode(data.toJson());
+
+class TopLevel {
+    final String topLevelHashCode;
+    final String topLevelNoSuchMethod;
+    final int topLevelRuntimeType;
+    final bool topLevelToString;
+
+    TopLevel({
+        required this.topLevelHashCode,
+        required this.topLevelNoSuchMethod,
+        required this.topLevelRuntimeType,
+        required this.topLevelToString,
+    });
+
+    factory TopLevel.fromJson(Map<String, dynamic> json) => TopLevel(
+        topLevelHashCode: json["hashCode"],
+        topLevelNoSuchMethod: json["noSuchMethod"],
+        topLevelRuntimeType: json["runtimeType"],
+        topLevelToString: json["toString"],
+    );
+
+    Map<String, dynamic> toJson() => {
+        "hashCode": topLevelHashCode,
+        "noSuchMethod": topLevelNoSuchMethod,
+        "runtimeType": topLevelRuntimeType,
+        "toString": topLevelToString,
+    };
+}
diff --git a/head/elixir/test/inputs/json/samples/dart-object-members.json/default/QuickType.ex b/head/elixir/test/inputs/json/samples/dart-object-members.json/default/QuickType.ex
new file mode 100644
index 0000000..64d0a8b
--- /dev/null
+++ b/head/elixir/test/inputs/json/samples/dart-object-members.json/default/QuickType.ex
@@ -0,0 +1,72 @@
+# This file was autogenerated using quicktype https://github.com/quicktype/quicktype
+#
+# Add Jason to your mix.exs
+#
+# Decode a JSON string: TopLevel.from_json(data)
+# Encode into a JSON string: TopLevel.to_json(struct)
+
+defmodule TopLevel do
+  @enforce_keys [:hash_code, :no_such_method, :runtime_type, :to_string]
+  defstruct [:hash_code, :no_such_method, :runtime_type, :to_string]
+
+  @type t :: %__MODULE__{
+          hash_code: String.t(),
+          no_such_method: String.t(),
+          runtime_type: integer(),
+          to_string: boolean()
+        }
+
+  def decode_hash_code(value) when is_binary(value), do: value
+  def decode_hash_code(_), do: {:error, "Unexpected type when decoding TopLevel.hash_code"}
+
+  def encode_hash_code(value) when is_binary(value), do: value
+  def encode_hash_code(_), do: {:error, "Unexpected type when encoding TopLevel.hash_code"}
+
+  def decode_no_such_method(value) when is_binary(value), do: value
+  def decode_no_such_method(_), do: {:error, "Unexpected type when decoding TopLevel.no_such_method"}
+
+  def encode_no_such_method(value) when is_binary(value), do: value
+  def encode_no_such_method(_), do: {:error, "Unexpected type when encoding TopLevel.no_such_method"}
+
+  def decode_runtime_type(value) when is_integer(value), do: value
+  def decode_runtime_type(_), do: {:error, "Unexpected type when decoding TopLevel.runtime_type"}
+
+  def encode_runtime_type(value) when is_integer(value), do: value
+  def encode_runtime_type(_), do: {:error, "Unexpected type when encoding TopLevel.runtime_type"}
+
+  def decode_to_string(value) when is_boolean(value), do: value
+  def decode_to_string(_), do: {:error, "Unexpected type when decoding TopLevel.to_string"}
+
+  def encode_to_string(value) when is_boolean(value), do: value
+  def encode_to_string(_), do: {:error, "Unexpected type when encoding TopLevel.to_string"}
+
+  def from_map(m) do
+    %TopLevel{
+      hash_code: decode_hash_code(m["hashCode"]),
+      no_such_method: decode_no_such_method(m["noSuchMethod"]),
+      runtime_type: decode_runtime_type(m["runtimeType"]),
+      to_string: decode_to_string(m["toString"]),
+    }
+  end
+
+  def from_json(json) do
+    json
+          |> Jason.decode!()
+          |> from_map()
+  end
+
+  def to_map(struct) do
+    %{
+      "hashCode" => struct.hash_code,
+      "noSuchMethod" => struct.no_such_method,
+      "runtimeType" => struct.runtime_type,
+      "toString" => struct.to_string,
+    }
+  end
+
+  def to_json(struct) do
+    struct
+          |> to_map()
+          |> Jason.encode!()
+  end
+end
diff --git a/head/elm/test/inputs/json/samples/dart-object-members.json/default/QuickType.elm b/head/elm/test/inputs/json/samples/dart-object-members.json/default/QuickType.elm
new file mode 100644
index 0000000..80b0161
--- /dev/null
+++ b/head/elm/test/inputs/json/samples/dart-object-members.json/default/QuickType.elm
@@ -0,0 +1,66 @@
+-- To decode the JSON data, add this file to your project, run
+--
+--     elm install NoRedInk/elm-json-decode-pipeline
+--
+-- add these imports
+--
+--     import Json.Decode exposing (decodeString)
+--     import QuickType exposing (quickType)
+--
+-- and you're off to the races with
+--
+--     decodeString quickType myJsonString
+
+module QuickType exposing
+    ( QuickType
+    , quickTypeToString
+    , quickType
+    )
+
+import Json.Decode as Jdec
+import Json.Decode.Pipeline as Jpipe
+import Json.Encode as Jenc
+import Dict exposing (Dict)
+
+type alias QuickType =
+    { hashCode : String
+    , noSuchMethod : String
+    , runtimeType : Int
+    , toString : Bool
+    }
+
+-- decoders and encoders
+optionalField key decoder fallback =
+    Jdec.dict Jdec.value
+        |> Jdec.andThen (\m ->
+            case Dict.get key m of
+                Nothing -> Jdec.succeed fallback
+                Just x -> Jdec.decodeValue decoder x |> Result.map Jdec.succeed |> Result.withDefault (Jdec.fail ("Invalid " ++ key)))
+
+quickTypeToString : QuickType -> String
+quickTypeToString r = Jenc.encode 0 (encodeQuickType r)
+
+quickType : Jdec.Decoder QuickType
+quickType =
+    Jdec.succeed QuickType
+        |> Jpipe.required "hashCode" Jdec.string
+        |> Jpipe.required "noSuchMethod" Jdec.string
+        |> Jpipe.required "runtimeType" Jdec.int
+        |> Jpipe.required "toString" Jdec.bool
+
+encodeQuickType : QuickType -> Jenc.Value
+encodeQuickType x =
+    Jenc.object
+        [ ("hashCode", Jenc.string x.hashCode)
+        , ("noSuchMethod", Jenc.string x.noSuchMethod)
+        , ("runtimeType", Jenc.int x.runtimeType)
+        , ("toString", Jenc.bool x.toString)
+        ]
+
+--- encoder helpers
+
+makeNullableEncoder : (a -> Jenc.Value) -> Maybe a -> Jenc.Value
+makeNullableEncoder f m =
+    case m of
+    Just x -> f x
+    Nothing -> Jenc.null
diff --git a/head/flow/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js b/head/flow/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js
new file mode 100644
index 0000000..f83e096
--- /dev/null
+++ b/head/flow/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js
@@ -0,0 +1,215 @@
+// @flow
+
+// To parse this data:
+//
+//   const Convert = require("./TopLevel");
+//
+//   const topLevel = Convert.toTopLevel(json);
+//
+// These functions will throw an error if the JSON doesn't
+// match the expected interface, even if the JSON is valid.
+
+export type TopLevel = {
+    hashCode:     string;
+    noSuchMethod: string;
+    runtimeType:  number;
+    toString:     boolean;
+};
+
+// Converts JSON strings to/from your types
+// and asserts the results of JSON.parse at runtime
+function toTopLevel(json: string): TopLevel {
+    return cast(JSON.parse(json), r("TopLevel"));
+}
+
+function topLevelToJson(value: TopLevel): string {
+    return JSON.stringify(uncast(value, r("TopLevel")), null, 2);
+}
+
+function invalidValue(typ: any, val: any, key: any, parent: any = '') {
+    const prettyTyp = prettyTypeName(typ);
+    const parentText = parent ? ` on ${parent}` : '';
+    const keyText = key ? ` for key "${key}"` : '';
+    throw Error(`Invalid value${keyText}${parentText}. Expected ${prettyTyp} but got ${JSON.stringify(val)}`);
+}
+
+function prettyTypeName(typ: any): string {
+    if (Array.isArray(typ)) {
+        if (typ.length === 2 && typ[0] === undefined) {
+            return `an optional ${prettyTypeName(typ[1])}`;
+        } else {
+            return `one of [${typ.map(a => { return prettyTypeName(a); }).join(", ")}]`;
+        }
+    } else if (typeof typ === "object" && typ.literal !== undefined) {
+        return typ.literal;
+    } else {
+        return typeof typ;
+    }
+}
+
+function jsonToJSProps(typ: any): any {
+    if (typ.jsonToJS === undefined) {
+        const map: any = {};
+        typ.props.forEach((p: any) => map[p.json] = { key: p.js, typ: p.typ });
+        typ.jsonToJS = map;
+    }
+    return typ.jsonToJS;
+}
+
+function jsToJSONProps(typ: any): any {
+    if (typ.jsToJSON === undefined) {
+        const map: any = {};
+        typ.props.forEach((p: any) => map[p.js] = { key: p.json, typ: p.typ });
+        typ.jsToJSON = map;
+    }
+    return typ.jsToJSON;
+}
+
+function transform(val: any, typ: any, getProps: any, key: any = '', parent: any = ''): any {
+    function transformPrimitive(typ: string, val: any): any {
+        if (typeof typ === typeof val) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+
+    function transformUnion(typs: any[], val: any): any {
+        // val must validate against one typ in typs
+        const l = typs.length;
+        for (let i = 0; i < l; i++) {
+            const typ = typs[i];
+            try {
+                return transform(val, typ, getProps);
+            } catch (_) {}
+        }
+        return invalidValue(typs, val, key, parent);
+    }
+
+    function transformEnum(cases: string[], val: any): any {
+        if (cases.indexOf(val) !== -1) return val;
+        return invalidValue(cases.map(a => { return l(a); }), val, key, parent);
+    }
+
+    function transformArray(typ: any, val: any): any {
+        // val must be an array with no invalid elements
+        if (!Array.isArray(val)) return invalidValue(l("array"), val, key, parent);
+
+        return val.map(el => transform(el, typ, getProps));
+    }
+
+    function transformDate(val: any): any {
+        if (val === null) {
+            return null;
+        }
+        const d = new Date(val);
+        if (isNaN(d.valueOf())) {
+            return invalidValue(l("Date"), val, key, parent);
+        }
+        return d;
+    }
+
+    function transformObject(props: { [k: string]: any }, additional: any, val: any): any {
+        if (val === null || typeof val !== "object" || Array.isArray(val)) {
+            return invalidValue(l(ref || "object"), val, key, parent);
+        }
+        const result: any = {};
+        Object.getOwnPropertyNames(props).forEach(key => {
+            const prop = props[key];
+            const v = Object.prototype.hasOwnProperty.call(val, key) ? val[key] : undefined;
+            result[prop.key] = transform(v, prop.typ, getProps, key, ref);
+        });
+        Object.getOwnPropertyNames(val).forEach(key => {
+            if (!Object.prototype.hasOwnProperty.call(props, key)) {
+                result[key] = transform(val[key], additional, getProps, key, ref);
+            }
+        });
+        return result;
+    }
+
+    if (typ === "any") return val;
+    if (typ === null) {
+        if (val === null) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+    if (typ === false) return invalidValue(typ, val, key, parent);
+    let ref: any = undefined;
+    while (typeof typ === "object" && typ.ref !== undefined) {
+        ref = typ.ref;
+        typ = typeMap[typ.ref];
+    }
+    if (Array.isArray(typ)) return transformEnum(typ, val);
+    if (typeof typ === "object") {
+        return typ.hasOwnProperty("pattern")      ? typeof val === "string" && new RegExp(typ.pattern).test(val) ? val : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("string")       ? typeof val === "string" && (typ.min === undefined || val.length >= typ.min) && (typ.max === undefined || val.length <= typ.max) ? transform(val, typ.string, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("number")       ? typeof val === "number" && (typ.min === undefined || val >= typ.min) && (typ.max === undefined || val <= typ.max) ? transform(val, typ.number, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("integer")      ? typeof val === "number" && val % 1 === 0 ? val : invalidValue(l("integer"), val, key, parent)
+            : typ.hasOwnProperty("unionMembers") ? transformUnion(typ.unionMembers, val)
+            : typ.hasOwnProperty("arrayItems")    ? transformArray(typ.arrayItems, val)
+            : typ.hasOwnProperty("props")         ? transformObject(getProps(typ), typ.additional, val)
+            : invalidValue(typ, val, key, parent);
+    }
+    // Numbers can be parsed by Date but shouldn't be.
+    if (typ === Date && typeof val !== "number") return transformDate(val);
+    return transformPrimitive(typ, val);
+}
+
+function cast<T>(val: any, typ: any): T {
+    return transform(val, typ, jsonToJSProps);
+}
+
+function uncast<T>(val: T, typ: any): any {
+    return transform(val, typ, jsToJSONProps);
+}
+
+function l(typ: any) {
+    return { literal: typ };
+}
+
+function a(typ: any) {
+    return { arrayItems: typ };
+}
+
+function i(typ: any) {
+    return { integer: typ };
+}
+
+function p(pattern: any) {
+    return { pattern };
+}
+
+function s(typ: any, min: any, max: any) {
+    return { string: typ, min, max };
+}
+
+function n(typ: any, min: any, max: any) {
+    return { number: typ, min, max };
+}
+
+function u(...typs: any[]) {
+    return { unionMembers: typs };
+}
+
+function o(props: any[], additional: any) {
+    return { props, additional };
+}
+
+function m(additional: any) {
+    const props: any[] = [];
+    return { props, additional };
+}
+
+function r(name: string) {
+    return { ref: name };
+}
+
+const typeMap: any = {
+    "TopLevel": o([
+        { json: "hashCode", js: "hashCode", typ: "" },
+        { json: "noSuchMethod", js: "noSuchMethod", typ: "" },
+        { json: "runtimeType", js: "runtimeType", typ: i(0) },
+        { json: "toString", js: "toString", typ: true },
+    ], false),
+};
+
+module.exports = {
+    "topLevelToJson": topLevelToJson,
+    "toTopLevel": toTopLevel,
+};
diff --git a/head/golang/test/inputs/json/samples/dart-object-members.json/default/quicktype.go b/head/golang/test/inputs/json/samples/dart-object-members.json/default/quicktype.go
new file mode 100644
index 0000000..afd2f75
--- /dev/null
+++ b/head/golang/test/inputs/json/samples/dart-object-members.json/default/quicktype.go
@@ -0,0 +1,26 @@
+// Code generated from JSON Schema using quicktype. DO NOT EDIT.
+// To parse and unparse this JSON data, add this code to your project and do:
+//
+//    topLevel, err := UnmarshalTopLevel(bytes)
+//    bytes, err = topLevel.Marshal()
+
+package main
+
+import "encoding/json"
+
+func UnmarshalTopLevel(data []byte) (TopLevel, error) {
+	var r TopLevel
+	err := json.Unmarshal(data, &r)
+	return r, err
+}
+
+func (r *TopLevel) Marshal() ([]byte, error) {
+	return json.Marshal(r)
+}
+
+type TopLevel struct {
+	HashCode     string `json:"hashCode"`
+	NoSuchMethod string `json:"noSuchMethod"`
+	RuntimeType  int64  `json:"runtimeType"`
+	ToString     bool   `json:"toString"`
+}
diff --git a/head/haskell/test/inputs/json/samples/dart-object-members.json/default/QuickType.hs b/head/haskell/test/inputs/json/samples/dart-object-members.json/default/QuickType.hs
new file mode 100644
index 0000000..d980e9a
--- /dev/null
+++ b/head/haskell/test/inputs/json/samples/dart-object-members.json/default/QuickType.hs
@@ -0,0 +1,39 @@
+{-# LANGUAGE StrictData #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module QuickType
+    ( QuickType (..)
+    , decodeTopLevel
+    ) where
+
+import Data.Aeson
+import Data.Aeson.Types (emptyObject)
+import Data.ByteString.Lazy (ByteString)
+import Data.HashMap.Strict (HashMap)
+import Data.Text (Text)
+
+data QuickType = QuickType
+    { hashCodeQuickType :: Text
+    , noSuchMethodQuickType :: Text
+    , runtimeTypeQuickType :: Int
+    , toStringQuickType :: Bool
+    } deriving (Show)
+
+decodeTopLevel :: ByteString -> Maybe QuickType
+decodeTopLevel = decode
+
+instance ToJSON QuickType where
+    toJSON (QuickType hashCodeQuickType noSuchMethodQuickType runtimeTypeQuickType toStringQuickType) =
+        object
+        [ "hashCode" .= hashCodeQuickType
+        , "noSuchMethod" .= noSuchMethodQuickType
+        , "runtimeType" .= runtimeTypeQuickType
+        , "toString" .= toStringQuickType
+        ]
+
+instance FromJSON QuickType where
+    parseJSON (Object v) = QuickType
+        <$> v .: "hashCode"
+        <*> v .: "noSuchMethod"
+        <*> v .: "runtimeType"
+        <*> v .: "toString"
diff --git a/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java b/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
new file mode 100644
index 0000000..d243dc1
--- /dev/null
+++ b/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
@@ -0,0 +1,103 @@
+// To use this code, add the following Maven dependency to your project:
+//
+//
+//     com.fasterxml.jackson.core     : jackson-databind          : 2.9.0
+//     com.fasterxml.jackson.datatype : jackson-datatype-jsr310   : 2.9.0
+//
+// Import this package:
+//
+//     import io.quicktype.Converter;
+//
+// Then you can deserialize a JSON string with
+//
+//     TopLevel data = Converter.fromJsonString(jsonString);
+
+package io.quicktype;
+
+import java.io.IOException;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import java.util.*;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.time.OffsetTime;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+import java.time.temporal.ChronoField;
+
+public class Converter {
+    // Date-time helpers
+
+    private static final DateTimeFormatter DATE_TIME_FORMATTER = new DateTimeFormatterBuilder()
+            .appendOptional(DateTimeFormatter.ISO_DATE_TIME)
+            .appendOptional(DateTimeFormatter.ISO_OFFSET_DATE_TIME)
+            .appendOptional(DateTimeFormatter.ISO_INSTANT)
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SX"))
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ssX"))
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))
+            .toFormatter()
+            .withZone(ZoneOffset.UTC);
+
+    public static OffsetDateTime parseDateTimeString(String str) {
+        return ZonedDateTime.from(Converter.DATE_TIME_FORMATTER.parse(str)).toOffsetDateTime();
+    }
+
+    private static final DateTimeFormatter TIME_FORMATTER = new DateTimeFormatterBuilder()
+            .appendOptional(DateTimeFormatter.ISO_TIME)
+            .appendOptional(DateTimeFormatter.ISO_OFFSET_TIME)
+            .parseDefaulting(ChronoField.YEAR, 2020)
+            .parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
+            .parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
+            .toFormatter()
+            .withZone(ZoneOffset.UTC);
+
+    public static OffsetTime parseTimeString(String str) {
+        return ZonedDateTime.from(Converter.TIME_FORMATTER.parse(str)).toOffsetDateTime().toOffsetTime();
+    }
+    // Serialize/deserialize helpers
+
+    public static TopLevel fromJsonString(String json) throws IOException {
+        return getObjectReader().readValue(json);
+    }
+
+    public static String toJsonString(TopLevel obj) throws JsonProcessingException {
+        return getObjectWriter().writeValueAsString(obj);
+    }
+
+    private static ObjectReader reader;
+    private static ObjectWriter writer;
+
+    private static void instantiateMapper() {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.findAndRegisterModules();
+        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+        mapper.configure(DeserializationFeature.ACCEPT_FLOAT_AS_INT, false);
+        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
+        SimpleModule module = new SimpleModule();
+        module.addDeserializer(OffsetDateTime.class, new JsonDeserializer<OffsetDateTime>() {
+            @Override
+            public OffsetDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
+                String value = jsonParser.getText();
+                return Converter.parseDateTimeString(value);
+            }
+        });
+        mapper.registerModule(module);
+        reader = mapper.readerFor(TopLevel.class);
+        writer = mapper.writerFor(TopLevel.class);
+    }
+
+    private static ObjectReader getObjectReader() {
+        if (reader == null) instantiateMapper();
+        return reader;
+    }
+
+    private static ObjectWriter getObjectWriter() {
+        if (writer == null) instantiateMapper();
+        return writer;
+    }
+}
diff --git a/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java b/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
new file mode 100644
index 0000000..f202c1a
--- /dev/null
+++ b/head/java/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
@@ -0,0 +1,30 @@
+package io.quicktype;
+
+import com.fasterxml.jackson.annotation.*;
+
+public class TopLevel {
+    private String hashCode;
+    private String noSuchMethod;
+    private long runtimeType;
+    private boolean toString;
+
+    @JsonProperty("hashCode")
+    public String getHashCode() { return hashCode; }
+    @JsonProperty("hashCode")
+    public void setHashCode(String value) { this.hashCode = value; }
+
+    @JsonProperty("noSuchMethod")
+    public String getNoSuchMethod() { return noSuchMethod; }
+    @JsonProperty("noSuchMethod")
+    public void setNoSuchMethod(String value) { this.noSuchMethod = value; }
+
+    @JsonProperty("runtimeType")
+    public long getRuntimeType() { return runtimeType; }
+    @JsonProperty("runtimeType")
+    public void setRuntimeType(long value) { this.runtimeType = value; }
+
+    @JsonProperty("toString")
+    public boolean getToString() { return toString; }
+    @JsonProperty("toString")
+    public void setToString(boolean value) { this.toString = value; }
+}
diff --git a/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java b/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
new file mode 100644
index 0000000..aeaa704
--- /dev/null
+++ b/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
@@ -0,0 +1,124 @@
+// To use this code, add the following Maven dependency to your project:
+//
+//
+//     com.fasterxml.jackson.core     : jackson-databind          : 2.9.0
+//
+//
+// Import this package:
+//
+//     import io.quicktype.Converter;
+//
+// Then you can deserialize a JSON string with
+//
+//     TopLevel data = Converter.fromJsonString(jsonString);
+
+package io.quicktype;
+
+import java.io.IOException;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import java.util.*;
+import java.util.Date;
+import java.text.SimpleDateFormat;
+
+public class Converter {
+    // Date-time helpers
+
+    private static final String[] DATE_TIME_FORMATS = {
+            "yyyy-MM-dd'T'HH:mm:ss.SX",
+            "yyyy-MM-dd'T'HH:mm:ss.S",
+            "yyyy-MM-dd'T'HH:mm:ssX",
+            "yyyy-MM-dd'T'HH:mm:ss",
+            "yyyy-MM-dd HH:mm:ss.SX",
+            "yyyy-MM-dd HH:mm:ss.S",
+            "yyyy-MM-dd HH:mm:ssX",
+            "yyyy-MM-dd HH:mm:ss",
+            "HH:mm:ss.SZ",
+            "HH:mm:ss.S",
+            "HH:mm:ssZ",
+            "HH:mm:ss",
+            "yyyy-MM-dd",
+    };
+
+    public static Date parseAllDateTimeString(String str) {
+        str = str.replaceFirst("(\\.\\d{3})\\d+", "$1");
+        for (String format : DATE_TIME_FORMATS) {
+            try {
+                return new SimpleDateFormat(format).parse(str);
+            } catch (Exception ex) {
+                // Ignored
+            }
+        }
+        return null;
+    }
+
+    public static String serializeDateTime(Date datetime) {
+        return new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ssZ").format(datetime);
+    }
+
+    public static String serializeDate(Date datetime) {
+        return new SimpleDateFormat("yyyy-MM-dd").format(datetime);
+    }
+
+    public static String serializeTime(Date datetime) {
+        return new SimpleDateFormat("hh:mm:ssZ").format(datetime);
+    }
+    // Serialize/deserialize helpers
+
+    public static TopLevel fromJsonString(String json) throws IOException {
+        return getObjectReader().readValue(json);
+    }
+
+    public static String toJsonString(TopLevel obj) throws JsonProcessingException {
+        return getObjectWriter().writeValueAsString(obj);
+    }
+
+    private static ObjectReader reader;
+    private static ObjectWriter writer;
+
+    private static void instantiateMapper() {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.findAndRegisterModules();
+        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+        mapper.configure(DeserializationFeature.ACCEPT_FLOAT_AS_INT, false);
+        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
+        SimpleModule module = new SimpleModule();
+        module.addDeserializer(Date.class, new JsonDeserializer<Date>() {
+            @Override
+            public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
+                String value = jsonParser.getText();
+                return Converter.parseAllDateTimeString(value);
+            }
+        });
+        module.addDeserializer(Date.class, new JsonDeserializer<Date>() {
+            @Override
+            public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
+                String value = jsonParser.getText();
+                return Converter.parseAllDateTimeString(value);
+            }
+        });
+        module.addDeserializer(Date.class, new JsonDeserializer<Date>() {
+            @Override
+            public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
+                String value = jsonParser.getText();
+                return Converter.parseAllDateTimeString(value);
+            }
+        });
+        mapper.registerModule(module);
+        reader = mapper.readerFor(TopLevel.class);
+        writer = mapper.writerFor(TopLevel.class);
+    }
+
+    private static ObjectReader getObjectReader() {
+        if (reader == null) instantiateMapper();
+        return reader;
+    }
+
+    private static ObjectWriter getObjectWriter() {
+        if (writer == null) instantiateMapper();
+        return writer;
+    }
+}
diff --git a/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java b/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
new file mode 100644
index 0000000..f202c1a
--- /dev/null
+++ b/head/java-datetime-legacy/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
@@ -0,0 +1,30 @@
+package io.quicktype;
+
+import com.fasterxml.jackson.annotation.*;
+
+public class TopLevel {
+    private String hashCode;
+    private String noSuchMethod;
+    private long runtimeType;
+    private boolean toString;
+
+    @JsonProperty("hashCode")
+    public String getHashCode() { return hashCode; }
+    @JsonProperty("hashCode")
+    public void setHashCode(String value) { this.hashCode = value; }
+
+    @JsonProperty("noSuchMethod")
+    public String getNoSuchMethod() { return noSuchMethod; }
+    @JsonProperty("noSuchMethod")
+    public void setNoSuchMethod(String value) { this.noSuchMethod = value; }
+
+    @JsonProperty("runtimeType")
+    public long getRuntimeType() { return runtimeType; }
+    @JsonProperty("runtimeType")
+    public void setRuntimeType(long value) { this.runtimeType = value; }
+
+    @JsonProperty("toString")
+    public boolean getToString() { return toString; }
+    @JsonProperty("toString")
+    public void setToString(boolean value) { this.toString = value; }
+}
diff --git a/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java b/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
new file mode 100644
index 0000000..d243dc1
--- /dev/null
+++ b/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/Converter.java
@@ -0,0 +1,103 @@
+// To use this code, add the following Maven dependency to your project:
+//
+//
+//     com.fasterxml.jackson.core     : jackson-databind          : 2.9.0
+//     com.fasterxml.jackson.datatype : jackson-datatype-jsr310   : 2.9.0
+//
+// Import this package:
+//
+//     import io.quicktype.Converter;
+//
+// Then you can deserialize a JSON string with
+//
+//     TopLevel data = Converter.fromJsonString(jsonString);
+
+package io.quicktype;
+
+import java.io.IOException;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import java.util.*;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.time.OffsetTime;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+import java.time.temporal.ChronoField;
+
+public class Converter {
+    // Date-time helpers
+
+    private static final DateTimeFormatter DATE_TIME_FORMATTER = new DateTimeFormatterBuilder()
+            .appendOptional(DateTimeFormatter.ISO_DATE_TIME)
+            .appendOptional(DateTimeFormatter.ISO_OFFSET_DATE_TIME)
+            .appendOptional(DateTimeFormatter.ISO_INSTANT)
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SX"))
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ssX"))
+            .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))
+            .toFormatter()
+            .withZone(ZoneOffset.UTC);
+
+    public static OffsetDateTime parseDateTimeString(String str) {
+        return ZonedDateTime.from(Converter.DATE_TIME_FORMATTER.parse(str)).toOffsetDateTime();
+    }
+
+    private static final DateTimeFormatter TIME_FORMATTER = new DateTimeFormatterBuilder()
+            .appendOptional(DateTimeFormatter.ISO_TIME)
+            .appendOptional(DateTimeFormatter.ISO_OFFSET_TIME)
+            .parseDefaulting(ChronoField.YEAR, 2020)
+            .parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
+            .parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
+            .toFormatter()
+            .withZone(ZoneOffset.UTC);
+
+    public static OffsetTime parseTimeString(String str) {
+        return ZonedDateTime.from(Converter.TIME_FORMATTER.parse(str)).toOffsetDateTime().toOffsetTime();
+    }
+    // Serialize/deserialize helpers
+
+    public static TopLevel fromJsonString(String json) throws IOException {
+        return getObjectReader().readValue(json);
+    }
+
+    public static String toJsonString(TopLevel obj) throws JsonProcessingException {
+        return getObjectWriter().writeValueAsString(obj);
+    }
+
+    private static ObjectReader reader;
+    private static ObjectWriter writer;
+
+    private static void instantiateMapper() {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.findAndRegisterModules();
+        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+        mapper.configure(DeserializationFeature.ACCEPT_FLOAT_AS_INT, false);
+        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
+        SimpleModule module = new SimpleModule();
+        module.addDeserializer(OffsetDateTime.class, new JsonDeserializer<OffsetDateTime>() {
+            @Override
+            public OffsetDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
+                String value = jsonParser.getText();
+                return Converter.parseDateTimeString(value);
+            }
+        });
+        mapper.registerModule(module);
+        reader = mapper.readerFor(TopLevel.class);
+        writer = mapper.writerFor(TopLevel.class);
+    }
+
+    private static ObjectReader getObjectReader() {
+        if (reader == null) instantiateMapper();
+        return reader;
+    }
+
+    private static ObjectWriter getObjectWriter() {
+        if (writer == null) instantiateMapper();
+        return writer;
+    }
+}
diff --git a/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java b/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
new file mode 100644
index 0000000..f202c1a
--- /dev/null
+++ b/head/java-lombok/test/inputs/json/samples/dart-object-members.json/default/src/main/java/io/quicktype/TopLevel.java
@@ -0,0 +1,30 @@
+package io.quicktype;
+
+import com.fasterxml.jackson.annotation.*;
+
+public class TopLevel {
+    private String hashCode;
+    private String noSuchMethod;
+    private long runtimeType;
+    private boolean toString;
+
+    @JsonProperty("hashCode")
+    public String getHashCode() { return hashCode; }
+    @JsonProperty("hashCode")
+    public void setHashCode(String value) { this.hashCode = value; }
+
+    @JsonProperty("noSuchMethod")
+    public String getNoSuchMethod() { return noSuchMethod; }
+    @JsonProperty("noSuchMethod")
+    public void setNoSuchMethod(String value) { this.noSuchMethod = value; }
+
+    @JsonProperty("runtimeType")
+    public long getRuntimeType() { return runtimeType; }
+    @JsonProperty("runtimeType")
+    public void setRuntimeType(long value) { this.runtimeType = value; }
+
+    @JsonProperty("toString")
+    public boolean getToString() { return toString; }
+    @JsonProperty("toString")
+    public void setToString(boolean value) { this.toString = value; }
+}
diff --git a/head/javascript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js b/head/javascript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js
new file mode 100644
index 0000000..583ad3c
--- /dev/null
+++ b/head/javascript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.js
@@ -0,0 +1,206 @@
+// To parse this data:
+//
+//   const Convert = require("./TopLevel");
+//
+//   const topLevel = Convert.toTopLevel(json);
+//
+// These functions will throw an error if the JSON doesn't
+// match the expected interface, even if the JSON is valid.
+
+// Converts JSON strings to/from your types
+// and asserts the results of JSON.parse at runtime
+function toTopLevel(json) {
+    return cast(JSON.parse(json), r("TopLevel"));
+}
+
+function topLevelToJson(value) {
+    return JSON.stringify(uncast(value, r("TopLevel")), null, 2);
+}
+
+function invalidValue(typ, val, key, parent = '') {
+    const prettyTyp = prettyTypeName(typ);
+    const parentText = parent ? ` on ${parent}` : '';
+    const keyText = key ? ` for key "${key}"` : '';
+    throw Error(`Invalid value${keyText}${parentText}. Expected ${prettyTyp} but got ${JSON.stringify(val)}`);
+}
+
+function prettyTypeName(typ) {
+    if (Array.isArray(typ)) {
+        if (typ.length === 2 && typ[0] === undefined) {
+            return `an optional ${prettyTypeName(typ[1])}`;
+        } else {
+            return `one of [${typ.map(a => { return prettyTypeName(a); }).join(", ")}]`;
+        }
+    } else if (typeof typ === "object" && typ.literal !== undefined) {
+        return typ.literal;
+    } else {
+        return typeof typ;
+    }
+}
+
+function jsonToJSProps(typ) {
+    if (typ.jsonToJS === undefined) {
+        const map = {};
+        typ.props.forEach((p) => map[p.json] = { key: p.js, typ: p.typ });
+        typ.jsonToJS = map;
+    }
+    return typ.jsonToJS;
+}
+
+function jsToJSONProps(typ) {
+    if (typ.jsToJSON === undefined) {
+        const map = {};
+        typ.props.forEach((p) => map[p.js] = { key: p.json, typ: p.typ });
+        typ.jsToJSON = map;
+    }
+    return typ.jsToJSON;
+}
+
+function transform(val, typ, getProps, key = '', parent = '') {
+    function transformPrimitive(typ, val) {
+        if (typeof typ === typeof val) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+
+    function transformUnion(typs, val) {
+        // val must validate against one typ in typs
+        const l = typs.length;
+        for (let i = 0; i < l; i++) {
+            const typ = typs[i];
+            try {
+                return transform(val, typ, getProps);
+            } catch (_) {}
+        }
+        return invalidValue(typs, val, key, parent);
+    }
+
+    function transformEnum(cases, val) {
+        if (cases.indexOf(val) !== -1) return val;
+        return invalidValue(cases.map(a => { return l(a); }), val, key, parent);
+    }
+
+    function transformArray(typ, val) {
+        // val must be an array with no invalid elements
+        if (!Array.isArray(val)) return invalidValue(l("array"), val, key, parent);
+
+        return val.map(el => transform(el, typ, getProps));
+    }
+
+    function transformDate(val) {
+        if (val === null) {
+            return null;
+        }
+        const d = new Date(val);
+        if (isNaN(d.valueOf())) {
+            return invalidValue(l("Date"), val, key, parent);
+        }
+        return d;
+    }
+
+    function transformObject(props, additional, val) {
+        if (val === null || typeof val !== "object" || Array.isArray(val)) {
+            return invalidValue(l(ref || "object"), val, key, parent);
+        }
+        const result = {};
+        Object.getOwnPropertyNames(props).forEach(key => {
+            const prop = props[key];
+            const v = Object.prototype.hasOwnProperty.call(val, key) ? val[key] : undefined;
+            result[prop.key] = transform(v, prop.typ, getProps, key, ref);
+        });
+        Object.getOwnPropertyNames(val).forEach(key => {
+            if (!Object.prototype.hasOwnProperty.call(props, key)) {
+                result[key] = transform(val[key], additional, getProps, key, ref);
+            }
+        });
+        return result;
+    }
+
+    if (typ === "any") return val;
+    if (typ === null) {
+        if (val === null) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+    if (typ === false) return invalidValue(typ, val, key, parent);
+    let ref = undefined;
+    while (typeof typ === "object" && typ.ref !== undefined) {
+        ref = typ.ref;
+        typ = typeMap[typ.ref];
+    }
+    if (Array.isArray(typ)) return transformEnum(typ, val);
+    if (typeof typ === "object") {
+        return typ.hasOwnProperty("pattern")      ? typeof val === "string" && new RegExp(typ.pattern).test(val) ? val : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("string")       ? typeof val === "string" && (typ.min === undefined || val.length >= typ.min) && (typ.max === undefined || val.length <= typ.max) ? transform(val, typ.string, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("number")       ? typeof val === "number" && (typ.min === undefined || val >= typ.min) && (typ.max === undefined || val <= typ.max) ? transform(val, typ.number, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("integer")      ? typeof val === "number" && val % 1 === 0 ? val : invalidValue(l("integer"), val, key, parent)
+            : typ.hasOwnProperty("unionMembers") ? transformUnion(typ.unionMembers, val)
+            : typ.hasOwnProperty("arrayItems")    ? transformArray(typ.arrayItems, val)
+            : typ.hasOwnProperty("props")         ? transformObject(getProps(typ), typ.additional, val)
+            : invalidValue(typ, val, key, parent);
+    }
+    // Numbers can be parsed by Date but shouldn't be.
+    if (typ === Date && typeof val !== "number") return transformDate(val);
+    return transformPrimitive(typ, val);
+}
+
+function cast(val, typ) {
+    return transform(val, typ, jsonToJSProps);
+}
+
+function uncast(val, typ) {
+    return transform(val, typ, jsToJSONProps);
+}
+
+function l(typ) {
+    return { literal: typ };
+}
+
+function a(typ) {
+    return { arrayItems: typ };
+}
+
+function i(typ) {
+    return { integer: typ };
+}
+
+function p(pattern) {
+    return { pattern };
+}
+
+function s(typ, min, max) {
+    return { string: typ, min, max };
+}
+
+function n(typ, min, max) {
+    return { number: typ, min, max };
+}
+
+function u(...typs) {
+    return { unionMembers: typs };
+}
+
+function o(props, additional) {
+    return { props, additional };
+}
+
+function m(additional) {
+    const props = [];
+    return { props, additional };
+}
+
+function r(name) {
+    return { ref: name };
+}
+
+const typeMap = {
+    "TopLevel": o([
+        { json: "hashCode", js: "hashCode", typ: "" },
+        { json: "noSuchMethod", js: "noSuchMethod", typ: "" },
+        { json: "runtimeType", js: "runtimeType", typ: i(0) },
+        { json: "toString", js: "toString", typ: true },
+    ], false),
+};
+
+module.exports = {
+    "topLevelToJson": topLevelToJson,
+    "toTopLevel": toTopLevel,
+};
diff --git a/head/javascript-prop-types/test/inputs/json/samples/dart-object-members.json/default/toplevel.js b/head/javascript-prop-types/test/inputs/json/samples/dart-object-members.json/default/toplevel.js
new file mode 100644
index 0000000..8ca66ee
--- /dev/null
+++ b/head/javascript-prop-types/test/inputs/json/samples/dart-object-members.json/default/toplevel.js
@@ -0,0 +1,24 @@
+// Example usage:
+//
+// import { MyShape } from ./myShape.js;
+//
+// class MyComponent extends React.Component {
+//   //
+// }
+//
+// MyComponent.propTypes = {
+//   input: MyShape
+// };
+
+import PropTypes from "prop-types";
+const Integer = (props, name) => props[name] == null || Number.isInteger(props[name]) ? null : new Error("Expected integer");
+
+let _TopLevel;
+_TopLevel = PropTypes.shape({
+    "hashCode": PropTypes.oneOfType([PropTypes.string]).isRequired,
+    "noSuchMethod": PropTypes.oneOfType([PropTypes.string]).isRequired,
+    "runtimeType": PropTypes.oneOfType([Integer]).isRequired,
+    "toString": PropTypes.oneOfType([PropTypes.bool]).isRequired,
+});
+
+export const TopLevel = _TopLevel;
diff --git a/head/kotlin/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt b/head/kotlin/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
new file mode 100644
index 0000000..e0f6e38
--- /dev/null
+++ b/head/kotlin/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
@@ -0,0 +1,22 @@
+// To parse the JSON, install Klaxon and do:
+//
+//   val topLevel = TopLevel.fromJson(jsonString)
+
+package quicktype
+
+import com.beust.klaxon.*
+
+private val klaxon = Klaxon()
+
+data class TopLevel (
+    val hashCode: String,
+    val noSuchMethod: String,
+    val runtimeType: Long,
+    val toString: Boolean
+) {
+    public fun toJson() = klaxon.toJsonString(this)
+
+    companion object {
+        public fun fromJson(json: String) = klaxon.parse<TopLevel>(json)
+    }
+}
diff --git a/head/kotlin-jackson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt b/head/kotlin-jackson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
new file mode 100644
index 0000000..e769147
--- /dev/null
+++ b/head/kotlin-jackson/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
@@ -0,0 +1,40 @@
+// To parse the JSON, install jackson-module-kotlin and do:
+//
+//   val topLevel = TopLevel.fromJson(jsonString)
+
+package quicktype
+
+import com.fasterxml.jackson.annotation.*
+import com.fasterxml.jackson.core.*
+import com.fasterxml.jackson.databind.*
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
+import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.databind.node.*
+import com.fasterxml.jackson.databind.ser.std.StdSerializer
+import com.fasterxml.jackson.module.kotlin.*
+
+val mapper = jacksonObjectMapper().apply {
+    propertyNamingStrategy = object : PropertyNamingStrategy.PropertyNamingStrategyBase() { override fun translate(name: String) = if (name == "empty") "" else name }
+    setSerializationInclusion(JsonInclude.Include.NON_NULL)
+    disable(DeserializationFeature.ACCEPT_FLOAT_AS_INT)
+}
+
+data class TopLevel (
+    @get:JsonProperty(required=true)@field:JsonProperty(required=true)
+    val hashCode: String,
+
+    @get:JsonProperty(required=true)@field:JsonProperty(required=true)
+    val noSuchMethod: String,
+
+    @get:JsonProperty(required=true)@field:JsonProperty(required=true)
+    val runtimeType: Long,
+
+    @get:JsonProperty(required=true)@field:JsonProperty(required=true)
+    val toString: Boolean
+) {
+    fun toJson() = mapper.writeValueAsString(this)
+
+    companion object {
+        fun fromJson(json: String) = mapper.readValue<TopLevel>(json)
+    }
+}
diff --git a/head/kotlinx/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt b/head/kotlinx/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
new file mode 100644
index 0000000..cf4cf8d
--- /dev/null
+++ b/head/kotlinx/test/inputs/json/samples/dart-object-members.json/default/TopLevel.kt
@@ -0,0 +1,19 @@
+// To parse the JSON, install kotlin's serialization plugin and do:
+//
+// val json     = Json { allowStructuredMapKeys = true }
+// val topLevel = json.parse(TopLevel.serializer(), jsonString)
+
+package quicktype
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.encoding.*
+
+@Serializable
+data class TopLevel (
+    val hashCode: String,
+    val noSuchMethod: String,
+    val runtimeType: Long,
+    val toString: Boolean
+)
diff --git a/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.h b/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.h
new file mode 100644
index 0000000..2f9fd63
--- /dev/null
+++ b/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.h
@@ -0,0 +1,33 @@
+// To parse this JSON:
+//
+//   NSError *error;
+//   QTTopLevel *topLevel = [QTTopLevel fromJSON:json encoding:NSUTF8Encoding error:&error];
+
+#import <Foundation/Foundation.h>
+
+@class QTTopLevel;
+
+NS_ASSUME_NONNULL_BEGIN
+
+#pragma mark - Top-level marshaling functions
+
+QTTopLevel *_Nullable QTTopLevelFromData(NSData *data, NSError **error);
+QTTopLevel *_Nullable QTTopLevelFromJSON(NSString *json, NSStringEncoding encoding, NSError **error);
+NSData     *_Nullable QTTopLevelToData(QTTopLevel *topLevel, NSError **error);
+NSString   *_Nullable QTTopLevelToJSON(QTTopLevel *topLevel, NSStringEncoding encoding, NSError **error);
+
+#pragma mark - Object interfaces
+
+@interface QTTopLevel : NSObject
+@property (nonatomic, assign) BOOL isToString;
+@property (nonatomic, copy)   NSString *noSuchMethod;
+@property (nonatomic, assign) NSInteger runtimeType;
+@property (nonatomic, copy)   NSString *theHashCode;
+
++ (_Nullable instancetype)fromJSON:(NSString *)json encoding:(NSStringEncoding)encoding error:(NSError *_Nullable *)error;
++ (_Nullable instancetype)fromData:(NSData *)data error:(NSError *_Nullable *)error;
+- (NSString *_Nullable)toJSON:(NSStringEncoding)encoding error:(NSError *_Nullable *)error;
+- (NSData *_Nullable)toData:(NSError *_Nullable *)error;
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.m b/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.m
new file mode 100644
index 0000000..35b5146
--- /dev/null
+++ b/head/objective-c/test/inputs/json/samples/dart-object-members.json/default/QTTopLevel.m
@@ -0,0 +1,134 @@
+#import "QTTopLevel.h"
+
+#define λ(decl, expr) (^(decl) { return (expr); })
+
+static id NSNullify(id _Nullable x) {
+    return (x == nil || x == NSNull.null) ? NSNull.null : x;
+}
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface QTTopLevel (JSONConversion)
++ (instancetype)fromJSONDictionary:(NSDictionary *)dict;
+- (NSDictionary *)JSONDictionary;
+@end
+
+#pragma mark - JSON serialization
+
+QTTopLevel *_Nullable QTTopLevelFromData(NSData *data, NSError **error)
+{
+    @try {
+        id json = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:error];
+        return *error ? nil : [QTTopLevel fromJSONDictionary:json];
+    } @catch (NSException *exception) {
+        *error = [NSError errorWithDomain:@"JSONSerialization" code:-1 userInfo:@{ @"exception": exception }];
+        return nil;
+    }
+}
+
+QTTopLevel *_Nullable QTTopLevelFromJSON(NSString *json, NSStringEncoding encoding, NSError **error)
+{
+    return QTTopLevelFromData([json dataUsingEncoding:encoding], error);
+}
+
+NSData *_Nullable QTTopLevelToData(QTTopLevel *topLevel, NSError **error)
+{
+    @try {
+        id json = [topLevel JSONDictionary];
+        NSData *data = [NSJSONSerialization dataWithJSONObject:json options:NSJSONWritingFragmentsAllowed error:error];
+        return *error ? nil : data;
+    } @catch (NSException *exception) {
+        *error = [NSError errorWithDomain:@"JSONSerialization" code:-1 userInfo:@{ @"exception": exception }];
+        return nil;
+    }
+}
+
+NSString *_Nullable QTTopLevelToJSON(QTTopLevel *topLevel, NSStringEncoding encoding, NSError **error)
+{
+    NSData *data = QTTopLevelToData(topLevel, error);
+    return data ? [[NSString alloc] initWithData:data encoding:encoding] : nil;
+}
+
+@implementation QTTopLevel
++ (NSDictionary<NSString *, NSString *> *)properties
+{
+    static NSDictionary<NSString *, NSString *> *properties;
+    return properties = properties ? properties : @{
+        @"toString": @"isToString",
+        @"noSuchMethod": @"noSuchMethod",
+        @"runtimeType": @"runtimeType",
+        @"hashCode": @"theHashCode",
+    };
+}
+
++ (_Nullable instancetype)fromData:(NSData *)data error:(NSError *_Nullable *)error
+{
+    return QTTopLevelFromData(data, error);
+}
+
++ (_Nullable instancetype)fromJSON:(NSString *)json encoding:(NSStringEncoding)encoding error:(NSError *_Nullable *)error
+{
+    return QTTopLevelFromJSON(json, encoding, error);
+}
+
++ (instancetype)fromJSONDictionary:(NSDictionary *)dict
+{
+    return [dict isKindOfClass:NSDictionary.class] ? [[QTTopLevel alloc] initWithJSONDictionary:dict] : nil;
+}
+
+- (instancetype)initWithJSONDictionary:(NSDictionary *)dict
+{
+    if (self = [super init]) {
+        if (![dict[@"toString"] isKindOfClass:NSNumber.class]) return nil;
+        if (![dict[@"noSuchMethod"] isKindOfClass:NSString.class]) return nil;
+        if (![dict[@"runtimeType"] isKindOfClass:NSNumber.class]) return nil;
+        if ([dict[@"runtimeType"] doubleValue] != [dict[@"runtimeType"] longLongValue]) return nil;
+        if (![dict[@"hashCode"] isKindOfClass:NSString.class]) return nil;
+        [self setValuesForKeysWithDictionary:dict];
+    }
+    return self;
+}
+
+- (void)setValue:(nullable id)value forKey:(NSString *)key
+{
+    id resolved = QTTopLevel.properties[key];
+    if (resolved) [super setValue:value forKey:resolved];
+}
+
+- (void)setNilValueForKey:(NSString *)key
+{
+    id resolved = QTTopLevel.properties[key];
+    if (resolved) [super setValue:@(0) forKey:resolved];
+}
+
+- (NSDictionary *)JSONDictionary
+{
+    id dict = [[self dictionaryWithValuesForKeys:QTTopLevel.properties.allValues] mutableCopy];
+
+    for (id jsonName in QTTopLevel.properties) {
+        id propertyName = QTTopLevel.properties[jsonName];
+        if (![jsonName isEqualToString:propertyName]) {
+            dict[jsonName] = dict[propertyName];
+            [dict removeObjectForKey:propertyName];
+        }
+    }
+
+    [dict addEntriesFromDictionary:@{
+        @"toString": _isToString ? @YES : @NO,
+    }];
+
+    return dict;
+}
+
+- (NSData *_Nullable)toData:(NSError *_Nullable *)error
+{
+    return QTTopLevelToData(self, error);
+}
+
+- (NSString *_Nullable)toJSON:(NSStringEncoding)encoding error:(NSError *_Nullable *)error
+{
+    return QTTopLevelToJSON(self, encoding, error);
+}
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/head/php/test/inputs/json/samples/dart-object-members.json/default/TopLevel.php b/head/php/test/inputs/json/samples/dart-object-members.json/default/TopLevel.php
new file mode 100644
index 0000000..90d6aa5
--- /dev/null
+++ b/head/php/test/inputs/json/samples/dart-object-members.json/default/TopLevel.php
@@ -0,0 +1,274 @@
+<?php
+declare(strict_types=1);
+
+// This is an autogenerated file:TopLevel
+
+class TopLevel {
+    private string $hashCode; // json:hashCode Required
+    private string $noSuchMethod; // json:noSuchMethod Required
+    private int $runtimeType; // json:runtimeType Required
+    private bool $toString; // json:toString Required
+
+    /**
+     * @param string $hashCode
+     * @param string $noSuchMethod
+     * @param int $runtimeType
+     * @param bool $toString
+     */
+    public function __construct(string $hashCode, string $noSuchMethod, int $runtimeType, bool $toString) {
+        $this->hashCode = $hashCode;
+        $this->noSuchMethod = $noSuchMethod;
+        $this->runtimeType = $runtimeType;
+        $this->toString = $toString;
+    }
+
+    /**
+     * @param string $value
+     * @throws Exception
+     * @return string
+     */
+    public static function fromHashCode(string $value): string {
+        return $value; /*string*/
+    }
+
+    /**
+     * @throws Exception
+     * @return string
+     */
+    public function toHashCode(): string {
+        if (TopLevel::validateHashCode($this->hashCode))  {
+            return $this->hashCode; /*string*/
+        }
+        throw new Exception('never get to this TopLevel::hashCode');
+    }
+
+    /**
+     * @param string
+     * @return bool
+     * @throws Exception
+     */
+    public static function validateHashCode(string $value): bool {
+        return true;
+    }
+
+    /**
+     * @throws Exception
+     * @return string
+     */
+    public function getHashCode(): string {
+        if (TopLevel::validateHashCode($this->hashCode))  {
+            return $this->hashCode;
+        }
+        throw new Exception('never get to getHashCode TopLevel::hashCode');
+    }
+
+    /**
+     * @return string
+     */
+    public static function sampleHashCode(): string {
+        return 'TopLevel::hashCode::31'; /*31:hashCode*/
+    }
+
+    /**
+     * @param string $value
+     * @throws Exception
+     * @return string
+     */
+    public static function fromNoSuchMethod(string $value): string {
+        return $value; /*string*/
+    }
+
+    /**
+     * @throws Exception
+     * @return string
+     */
+    public function toNoSuchMethod(): string {
+        if (TopLevel::validateNoSuchMethod($this->noSuchMethod))  {
+            return $this->noSuchMethod; /*string*/
+        }
+        throw new Exception('never get to this TopLevel::noSuchMethod');
+    }
+
+    /**
+     * @param string
+     * @return bool
+     * @throws Exception
+     */
+    public static function validateNoSuchMethod(string $value): bool {
+        return true;
+    }
+
+    /**
+     * @throws Exception
+     * @return string
+     */
+    public function getNoSuchMethod(): string {
+        if (TopLevel::validateNoSuchMethod($this->noSuchMethod))  {
+            return $this->noSuchMethod;
+        }
+        throw new Exception('never get to getNoSuchMethod TopLevel::noSuchMethod');
+    }
+
+    /**
+     * @return string
+     */
+    public static function sampleNoSuchMethod(): string {
+        return 'TopLevel::noSuchMethod::32'; /*32:noSuchMethod*/
+    }
+
+    /**
+     * @param int $value
+     * @throws Exception
+     * @return int
+     */
+    public static function fromRuntimeType(int $value): int {
+        return $value; /*int*/
+    }
+
+    /**
+     * @throws Exception
+     * @return int
+     */
+    public function toRuntimeType(): int {
+        if (TopLevel::validateRuntimeType($this->runtimeType))  {
+            return $this->runtimeType; /*int*/
+        }
+        throw new Exception('never get to this TopLevel::runtimeType');
+    }
+
+    /**
+     * @param int
+     * @return bool
+     * @throws Exception
+     */
+    public static function validateRuntimeType(int $value): bool {
+        return true;
+    }
+
+    /**
+     * @throws Exception
+     * @return int
+     */
+    public function getRuntimeType(): int {
+        if (TopLevel::validateRuntimeType($this->runtimeType))  {
+            return $this->runtimeType;
+        }
+        throw new Exception('never get to getRuntimeType TopLevel::runtimeType');
+    }
+
+    /**
+     * @return int
+     */
+    public static function sampleRuntimeType(): int {
+        return 33; /*33:runtimeType*/
+    }
+
+    /**
+     * @param bool $value
+     * @throws Exception
+     * @return bool
+     */
+    public static function fromToString(bool $value): bool {
+        return $value; /*bool*/
+    }
+
+    /**
+     * @throws Exception
+     * @return bool
+     */
+    public function toToString(): bool {
+        if (TopLevel::validateToString($this->toString))  {
+            return $this->toString; /*bool*/
+        }
+        throw new Exception('never get to this TopLevel::toString');
+    }
+
+    /**
+     * @param bool
+     * @return bool
+     * @throws Exception
+     */
+    public static function validateToString(bool $value): bool {
+        return true;
+    }
+
+    /**
+     * @throws Exception
+     * @return bool
+     */
+    public function getToString(): bool {
+        if (TopLevel::validateToString($this->toString))  {
+            return $this->toString;
+        }
+        throw new Exception('never get to getToString TopLevel::toString');
+    }
+
+    /**
+     * @return bool
+     */
+    public static function sampleToString(): bool {
+        return true; /*34:toString*/
+    }
+
+    /**
+     * @throws Exception
+     * @return bool
+     */
+    public function validate(): bool {
+        return TopLevel::validateHashCode($this->hashCode)
+        || TopLevel::validateNoSuchMethod($this->noSuchMethod)
+        || TopLevel::validateRuntimeType($this->runtimeType)
+        || TopLevel::validateToString($this->toString);
+    }
+
+    /**
+     * @return stdClass
+     * @throws Exception
+     */
+    public function to(): stdClass  {
+        $out = new stdClass();
+        $out->{'hashCode'} = $this->toHashCode();
+        $out->{'noSuchMethod'} = $this->toNoSuchMethod();
+        $out->{'runtimeType'} = $this->toRuntimeType();
+        $out->{'toString'} = $this->toToString();
+        return $out;
+    }
+
+    /**
+     * @param stdClass $obj
+     * @return TopLevel
+     * @throws Exception
+     */
+    public static function from(stdClass $obj): TopLevel {
+        if (!property_exists($obj, 'hashCode')) {
+            throw new Exception("Missing required property");
+        }
+        if (!property_exists($obj, 'noSuchMethod')) {
+            throw new Exception("Missing required property");
+        }
+        if (!property_exists($obj, 'runtimeType')) {
+            throw new Exception("Missing required property");
+        }
+        if (!property_exists($obj, 'toString')) {
+            throw new Exception("Missing required property");
+        }
+        return new TopLevel(
+         TopLevel::fromHashCode($obj->{'hashCode'})
+        ,TopLevel::fromNoSuchMethod($obj->{'noSuchMethod'})
+        ,TopLevel::fromRuntimeType($obj->{'runtimeType'})
+        ,TopLevel::fromToString($obj->{'toString'})
+        );
+    }
+
+    /**
+     * @return TopLevel
+     */
+    public static function sample(): TopLevel {
+        return new TopLevel(
+         TopLevel::sampleHashCode()
+        ,TopLevel::sampleNoSuchMethod()
+        ,TopLevel::sampleRuntimeType()
+        ,TopLevel::sampleToString()
+        );
+    }
+}
diff --git a/head/pike/test/inputs/json/samples/dart-object-members.json/default/TopLevel.pmod b/head/pike/test/inputs/json/samples/dart-object-members.json/default/TopLevel.pmod
new file mode 100644
index 0000000..45ce84e
--- /dev/null
+++ b/head/pike/test/inputs/json/samples/dart-object-members.json/default/TopLevel.pmod
@@ -0,0 +1,44 @@
+// This source has been automatically generated by quicktype.
+// ( https://github.com/quicktype/quicktype )
+//
+// To use this code, simply import it into your project as a Pike module.
+// To JSON-encode your object, you can pass it to `Standards.JSON.encode`
+// or call `encode_json` on it.
+//
+// To decode a JSON string, first pass it to `Standards.JSON.decode`,
+// and then pass the result to `<YourClass>_from_JSON`.
+// It will return an instance of <YourClass>.
+// Bear in mind that these functions have unexpected behavior,
+// and will likely throw an error, if the JSON string does not
+// match the expected interface, even if the JSON itself is valid.
+
+class TopLevel {
+    string hash_code;      // json: "hashCode"
+    string no_such_method; // json: "noSuchMethod"
+    int    runtime_type;   // json: "runtimeType"
+    bool   to_string;      // json: "toString"
+
+    string encode_json() {
+        mapping(string:mixed) json = ([
+            "hashCode" : hash_code,
+            "noSuchMethod" : no_such_method,
+            "runtimeType" : runtime_type,
+            "toString" : to_string,
+        ]);
+
+        return Standards.JSON.encode(json);
+    }
+}
+
+TopLevel TopLevel_from_JSON(mixed json) {
+    TopLevel retval = TopLevel();
+
+    retval.hash_code = json["hashCode"];
+    retval.no_such_method = json["noSuchMethod"];
+    if (!intp(json["runtimeType"])) error("Expected integer");
+    retval.runtime_type = json["runtimeType"];
+    if (json["toString"] != Standards.JSON.true && json["toString"] != Standards.JSON.false) error("Expected bool");
+    retval.to_string = json["toString"];
+
+    return retval;
+}
diff --git a/head/python/test/inputs/json/samples/dart-object-members.json/default/quicktype.py b/head/python/test/inputs/json/samples/dart-object-members.json/default/quicktype.py
new file mode 100644
index 0000000..780b63b
--- /dev/null
+++ b/head/python/test/inputs/json/samples/dart-object-members.json/default/quicktype.py
@@ -0,0 +1,58 @@
+from dataclasses import dataclass
+from typing import Any, TypeVar, Type, cast
+
+
+T = TypeVar("T")
+
+
+def from_str(x: Any) -> str:
+    assert isinstance(x, str)
+    return x
+
+
+def from_int(x: Any) -> int:
+    assert isinstance(x, int) and not isinstance(x, bool)
+    return x
+
+
+def from_bool(x: Any) -> bool:
+    assert isinstance(x, bool)
+    return x
+
+
+def to_class(c: Type[T], x: Any) -> dict:
+    assert isinstance(x, c)
+    return cast(Any, x).to_dict()
+
+
+@dataclass
+class TopLevel:
+    hash_code: str
+    no_such_method: str
+    runtime_type: int
+    to_string: bool
+
+    @staticmethod
+    def from_dict(obj: Any) -> 'TopLevel':
+        assert isinstance(obj, dict)
+        hash_code = from_str(obj.get("hashCode"))
+        no_such_method = from_str(obj.get("noSuchMethod"))
+        runtime_type = from_int(obj.get("runtimeType"))
+        to_string = from_bool(obj.get("toString"))
+        return TopLevel(hash_code, no_such_method, runtime_type, to_string)
+
+    def to_dict(self) -> dict:
+        result: dict = {}
+        result["hashCode"] = from_str(self.hash_code)
+        result["noSuchMethod"] = from_str(self.no_such_method)
+        result["runtimeType"] = from_int(self.runtime_type)
+        result["toString"] = from_bool(self.to_string)
+        return result
+
+
+def top_level_from_dict(s: Any) -> TopLevel:
+    return TopLevel.from_dict(s)
+
+
+def top_level_to_dict(x: TopLevel) -> Any:
+    return to_class(TopLevel, x)
diff --git a/head/ruby/test/inputs/json/samples/dart-object-members.json/default/TopLevel.rb b/head/ruby/test/inputs/json/samples/dart-object-members.json/default/TopLevel.rb
new file mode 100644
index 0000000..887ffc2
--- /dev/null
+++ b/head/ruby/test/inputs/json/samples/dart-object-members.json/default/TopLevel.rb
@@ -0,0 +1,56 @@
+# This code may look unusually verbose for Ruby (and it is), but
+# it performs some subtle and complex validation of JSON data.
+#
+# To parse this JSON, add 'dry-struct' and 'dry-types' gems, then do:
+#
+#   top_level = TopLevel.from_json! "{…}"
+#   puts top_level.hash_code
+#
+# If from_json! succeeds, the value returned matches the schema.
+
+require 'json'
+require 'dry-types'
+require 'dry-struct'
+
+module Types
+  include Dry.Types(default: :nominal)
+
+  Integer = Strict::Integer
+  Bool    = Strict::Bool
+  Hash    = Strict::Hash
+  String  = Strict::String
+end
+
+class TopLevel < Dry::Struct
+  attribute :hash_code,      Types::String
+  attribute :no_such_method, Types::String
+  attribute :runtime_type,   Types::Integer
+  attribute :to_string,      Types::Bool
+
+  def self.from_dynamic!(d)
+    d = Types::Hash[d]
+    new(
+      hash_code:      d.fetch("hashCode"),
+      no_such_method: d.fetch("noSuchMethod"),
+      runtime_type:   d.fetch("runtimeType"),
+      to_string:      d.fetch("toString"),
+    )
+  end
+
+  def self.from_json!(json)
+    from_dynamic!(JSON.parse(json))
+  end
+
+  def to_dynamic
+    {
+      "hashCode"     => hash_code,
+      "noSuchMethod" => no_such_method,
+      "runtimeType"  => runtime_type,
+      "toString"     => to_string,
+    }
+  end
+
+  def to_json(options = nil)
+    JSON.generate(to_dynamic, options)
+  end
+end
diff --git a/head/rust/test/inputs/json/samples/dart-object-members.json/default/module_under_test.rs b/head/rust/test/inputs/json/samples/dart-object-members.json/default/module_under_test.rs
new file mode 100644
index 0000000..343a17e
--- /dev/null
+++ b/head/rust/test/inputs/json/samples/dart-object-members.json/default/module_under_test.rs
@@ -0,0 +1,26 @@
+// Example code that deserializes and serializes the model.
+// extern crate serde;
+// #[macro_use]
+// extern crate serde_derive;
+// extern crate serde_json;
+//
+// use generated_module::TopLevel;
+//
+// fn main() {
+//     let json = r#"{"answer": 42}"#;
+//     let model: TopLevel = serde_json::from_str(&json).unwrap();
+// }
+
+use serde::{Serialize, Deserialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TopLevel {
+    pub hash_code: String,
+
+    pub no_such_method: String,
+
+    pub runtime_type: i64,
+
+    pub to_string: bool,
+}
diff --git a/head/scala3/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala b/head/scala3/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala
new file mode 100644
index 0000000..a17b14b
--- /dev/null
+++ b/head/scala3/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala
@@ -0,0 +1,25 @@
+package quicktype
+
+import io.circe.syntax._
+import io.circe._
+import cats.syntax.functor._
+
+// If a union has a null in, then we'll need this too... 
+type NullValue = None.type
+
+case class TopLevel (
+    val hashCodeValue : String,
+    val noSuchMethod : String,
+    val runtimeType : Long,
+    val toStringValue : Boolean
+)
+
+object TopLevel:
+    given io.circe.derivation.Configuration =
+        io.circe.derivation.Configuration.default.withTransformMemberNames(
+            io.circe.derivation.renaming.replaceWith(
+                "hashCodeValue" -> "hashCode",
+                "toStringValue" -> "toString"
+            )
+        )
+    given io.circe.Codec.AsObject[TopLevel] = io.circe.derivation.ConfiguredCodec.derived
diff --git a/head/scala3-upickle/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala b/head/scala3-upickle/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala
new file mode 100644
index 0000000..56618ac
--- /dev/null
+++ b/head/scala3-upickle/test/inputs/json/samples/dart-object-members.json/default/TopLevel.scala
@@ -0,0 +1,77 @@
+package quicktype
+
+// Custom pickler so that missing keys and JSON nulls both read as None,
+// and None is left out when writing (upickle's default for Option is a
+// JSON array).
+object OptionPickler extends upickle.AttributeTagged:
+    import upickle.default.Writer
+    import upickle.default.Reader
+    override implicit def OptionWriter[T: Writer]: Writer[Option[T]] =
+        implicitly[Writer[T]].comap[Option[T]] {
+            case None => null.asInstanceOf[T]
+            case Some(x) => x
+        }
+
+    override implicit def OptionReader[T: Reader]: Reader[Option[T]] = {
+        new Reader.Delegate[Any, Option[T]](implicitly[Reader[T]].map(Some(_))){
+        override def visitNull(index: Int) = None
+        }
+    }
+end OptionPickler
+
+// If a union has a null in, then we'll need this too...
+type NullValue = None.type
+given OptionPickler.ReadWriter[NullValue] = OptionPickler.readwriter[ujson.Value].bimap[NullValue](
+    _ => ujson.Null,
+    json => if json.isNull then None else throw new upickle.core.Abort("not null")
+)
+given OptionPickler.ReadWriter[java.time.Instant] = OptionPickler.readwriter[String].bimap(_.toString, java.time.Instant.parse)
+
+object JsonExt:
+    val valueReader = OptionPickler.readwriter[ujson.Value]
+
+    // upickle's built-in primitive readers are lenient -- the numeric and
+    // boolean readers accept strings, and the string reader accepts
+    // numbers and booleans -- so untagged unions need strict readers to
+    // pick the right member.
+    val strictString: OptionPickler.Reader[String] = valueReader.map {
+        case ujson.Str(s) => s
+        case json => throw new upickle.core.Abort("expected string, got " + json)
+    }
+    val strictLong: OptionPickler.Reader[Long] = valueReader.map {
+        case ujson.Num(n) if n.isWhole => n.toLong
+        case json => throw new upickle.core.Abort("expected integer, got " + json)
+    }
+    val strictDouble: OptionPickler.Reader[Double] = valueReader.map {
+        case ujson.Num(n) => n
+        case json => throw new upickle.core.Abort("expected number, got " + json)
+    }
+    val strictBoolean: OptionPickler.Reader[Boolean] = valueReader.map {
+        case ujson.Bool(b) => b
+        case json => throw new upickle.core.Abort("expected boolean, got " + json)
+    }
+
+    def badMerge[T](r1: => OptionPickler.Reader[?], rest: OptionPickler.Reader[?]*): OptionPickler.Reader[T] = valueReader.map { json =>
+        var t: T | Null = null
+        val stack       = Vector.newBuilder[Throwable]
+        (r1 +: rest).foreach { reader =>
+            if t == null then
+            try
+                t = OptionPickler.read[T](json, trace = true)(using reader.asInstanceOf[OptionPickler.Reader[T]])
+            catch
+                case exc => stack += exc
+        }
+        if t != null then t.nn else throw new Exception(json.toString(), stack.result().headOption.getOrElse(null))
+    }
+end JsonExt
+given OptionPickler.Reader[Long] = JsonExt.strictLong
+
+
+case class TopLevel (
+    @upickle.implicits.key("hashCode")
+    val hashCodeValue : String,
+    val noSuchMethod : String,
+    val runtimeType : Long,
+    @upickle.implicits.key("toString")
+    val toStringValue : Boolean
+) derives OptionPickler.ReadWriter
diff --git a/head/swift/test/inputs/json/samples/dart-object-members.json/default/quicktype.swift b/head/swift/test/inputs/json/samples/dart-object-members.json/default/quicktype.swift
new file mode 100644
index 0000000..303a126
--- /dev/null
+++ b/head/swift/test/inputs/json/samples/dart-object-members.json/default/quicktype.swift
@@ -0,0 +1,98 @@
+// This file was generated from JSON Schema using quicktype, do not modify it directly.
+// To parse the JSON, add this file to your project and do:
+//
+//   let topLevel = try TopLevel(json)
+
+import Foundation
+
+// MARK: - TopLevel
+struct TopLevel: Codable {
+    let hashCode: String
+    let noSuchMethod: String
+    let runtimeType: Int
+    let toString: Bool
+
+    enum CodingKeys: String, CodingKey {
+        case hashCode = "hashCode"
+        case noSuchMethod = "noSuchMethod"
+        case runtimeType = "runtimeType"
+        case toString = "toString"
+    }
+}
+
+// MARK: TopLevel convenience initializers and mutators
+
+extension TopLevel {
+    init(data: Data) throws {
+        self = try newJSONDecoder().decode(TopLevel.self, from: data)
+    }
+
+    init(_ json: String, using encoding: String.Encoding = .utf8) throws {
+        guard let data = json.data(using: encoding) else {
+            throw NSError(domain: "JSONDecoding", code: 0, userInfo: nil)
+        }
+        try self.init(data: data)
+    }
+
+    init(fromURL url: URL) throws {
+        try self.init(data: try Data(contentsOf: url))
+    }
+
+    func with(
+        hashCode: String? = nil,
+        noSuchMethod: String? = nil,
+        runtimeType: Int? = nil,
+        toString: Bool? = nil
+    ) -> TopLevel {
+        return TopLevel(
+            hashCode: hashCode ?? self.hashCode,
+            noSuchMethod: noSuchMethod ?? self.noSuchMethod,
+            runtimeType: runtimeType ?? self.runtimeType,
+            toString: toString ?? self.toString
+        )
+    }
+
+    func jsonData() throws -> Data {
+        return try newJSONEncoder().encode(self)
+    }
+
+    func jsonString(encoding: String.Encoding = .utf8) throws -> String? {
+        return String(data: try self.jsonData(), encoding: encoding)
+    }
+}
+
+// MARK: - Helper functions for creating encoders and decoders
+
+func newJSONDecoder() -> JSONDecoder {
+    let decoder = JSONDecoder()
+    decoder.dateDecodingStrategy = .custom({ (decoder) -> Date in
+        let container = try decoder.singleValueContainer()
+        let dateStr = try container.decode(String.self)
+
+        let formatter = DateFormatter()
+        formatter.calendar = Calendar(identifier: .iso8601)
+        formatter.locale = Locale(identifier: "en_US_POSIX")
+        formatter.timeZone = TimeZone(secondsFromGMT: 0)
+        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSXXXXX"
+        if let date = formatter.date(from: dateStr) {
+            return date
+        }
+        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssXXXXX"
+        if let date = formatter.date(from: dateStr) {
+            return date
+        }
+        throw DecodingError.typeMismatch(Date.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Could not decode date"))
+    })
+    return decoder
+}
+
+func newJSONEncoder() -> JSONEncoder {
+    let encoder = JSONEncoder()
+    let formatter = DateFormatter()
+    formatter.calendar = Calendar(identifier: .iso8601)
+    formatter.locale = Locale(identifier: "en_US_POSIX")
+    formatter.timeZone = TimeZone(secondsFromGMT: 0)
+    formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSSSSXXXXX"
+    encoder.dateEncodingStrategy = .formatted(formatter)
+    return encoder
+}
diff --git a/head/typescript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts b/head/typescript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
new file mode 100644
index 0000000..13942e2
--- /dev/null
+++ b/head/typescript/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
@@ -0,0 +1,210 @@
+// To parse this data:
+//
+//   import { Convert, TopLevel } from "./TopLevel";
+//
+//   const topLevel = Convert.toTopLevel(json);
+//
+// These functions will throw an error if the JSON doesn't
+// match the expected interface, even if the JSON is valid.
+
+export interface TopLevel {
+    hashCode:     string;
+    noSuchMethod: string;
+    runtimeType:  number;
+    toString:     boolean;
+}
+
+// Converts JSON strings to/from your types
+// and asserts the results of JSON.parse at runtime
+export class Convert {
+    public static toTopLevel(json: string): TopLevel {
+        return cast(JSON.parse(json), r("TopLevel"));
+    }
+
+    public static topLevelToJson(value: TopLevel): string {
+        return JSON.stringify(uncast(value, r("TopLevel")), null, 2);
+    }
+}
+
+function invalidValue(typ: any, val: any, key: any, parent: any = ''): never {
+    const prettyTyp = prettyTypeName(typ);
+    const parentText = parent ? ` on ${parent}` : '';
+    const keyText = key ? ` for key "${key}"` : '';
+    throw Error(`Invalid value${keyText}${parentText}. Expected ${prettyTyp} but got ${JSON.stringify(val)}`);
+}
+
+function prettyTypeName(typ: any): string {
+    if (Array.isArray(typ)) {
+        if (typ.length === 2 && typ[0] === undefined) {
+            return `an optional ${prettyTypeName(typ[1])}`;
+        } else {
+            return `one of [${typ.map(a => { return prettyTypeName(a); }).join(", ")}]`;
+        }
+    } else if (typeof typ === "object" && typ.literal !== undefined) {
+        return typ.literal;
+    } else {
+        return typeof typ;
+    }
+}
+
+function jsonToJSProps(typ: any): any {
+    if (typ.jsonToJS === undefined) {
+        const map: any = {};
+        typ.props.forEach((p: any) => map[p.json] = { key: p.js, typ: p.typ });
+        typ.jsonToJS = map;
+    }
+    return typ.jsonToJS;
+}
+
+function jsToJSONProps(typ: any): any {
+    if (typ.jsToJSON === undefined) {
+        const map: any = {};
+        typ.props.forEach((p: any) => map[p.js] = { key: p.json, typ: p.typ });
+        typ.jsToJSON = map;
+    }
+    return typ.jsToJSON;
+}
+
+function transform(val: any, typ: any, getProps: any, key: any = '', parent: any = ''): any {
+    function transformPrimitive(typ: string, val: any): any {
+        if (typeof typ === typeof val) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+
+    function transformUnion(typs: any[], val: any): any {
+        // val must validate against one typ in typs
+        const l = typs.length;
+        for (let i = 0; i < l; i++) {
+            const typ = typs[i];
+            try {
+                return transform(val, typ, getProps);
+            } catch (_) {}
+        }
+        return invalidValue(typs, val, key, parent);
+    }
+
+    function transformEnum(cases: string[], val: any): any {
+        if (cases.indexOf(val) !== -1) return val;
+        return invalidValue(cases.map(a => { return l(a); }), val, key, parent);
+    }
+
+    function transformArray(typ: any, val: any): any {
+        // val must be an array with no invalid elements
+        if (!Array.isArray(val)) return invalidValue(l("array"), val, key, parent);
+
+        return val.map(el => transform(el, typ, getProps));
+    }
+
+    function transformDate(val: any): any {
+        if (val === null) {
+            return null;
+        }
+        const d = new Date(val);
+        if (isNaN(d.valueOf())) {
+            return invalidValue(l("Date"), val, key, parent);
+        }
+        return d;
+    }
+
+    function transformObject(props: { [k: string]: any }, additional: any, val: any): any {
+        if (val === null || typeof val !== "object" || Array.isArray(val)) {
+            return invalidValue(l(ref || "object"), val, key, parent);
+        }
+        const result: any = {};
+        Object.getOwnPropertyNames(props).forEach(key => {
+            const prop = props[key];
+            const v = Object.prototype.hasOwnProperty.call(val, key) ? val[key] : undefined;
+            result[prop.key] = transform(v, prop.typ, getProps, key, ref);
+        });
+        Object.getOwnPropertyNames(val).forEach(key => {
+            if (!Object.prototype.hasOwnProperty.call(props, key)) {
+                result[key] = transform(val[key], additional, getProps, key, ref);
+            }
+        });
+        return result;
+    }
+
+    if (typ === "any") return val;
+    if (typ === null) {
+        if (val === null) return val;
+        return invalidValue(typ, val, key, parent);
+    }
+    if (typ === false) return invalidValue(typ, val, key, parent);
+    let ref: any = undefined;
+    while (typeof typ === "object" && typ.ref !== undefined) {
+        ref = typ.ref;
+        typ = typeMap[typ.ref];
+    }
+    if (Array.isArray(typ)) return transformEnum(typ, val);
+    if (typeof typ === "object") {
+        return typ.hasOwnProperty("pattern")      ? typeof val === "string" && new RegExp(typ.pattern).test(val) ? val : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("string")       ? typeof val === "string" && (typ.min === undefined || val.length >= typ.min) && (typ.max === undefined || val.length <= typ.max) ? transform(val, typ.string, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("number")       ? typeof val === "number" && (typ.min === undefined || val >= typ.min) && (typ.max === undefined || val <= typ.max) ? transform(val, typ.number, getProps, key, parent) : invalidValue(typ, val, key, parent)
+            : typ.hasOwnProperty("integer")      ? typeof val === "number" && val % 1 === 0 ? val : invalidValue(l("integer"), val, key, parent)
+            : typ.hasOwnProperty("unionMembers") ? transformUnion(typ.unionMembers, val)
+            : typ.hasOwnProperty("arrayItems")    ? transformArray(typ.arrayItems, val)
+            : typ.hasOwnProperty("props")         ? transformObject(getProps(typ), typ.additional, val)
+            : invalidValue(typ, val, key, parent);
+    }
+    // Numbers can be parsed by Date but shouldn't be.
+    if (typ === Date && typeof val !== "number") return transformDate(val);
+    return transformPrimitive(typ, val);
+}
+
+function cast<T>(val: any, typ: any): T {
+    return transform(val, typ, jsonToJSProps);
+}
+
+function uncast<T>(val: T, typ: any): any {
+    return transform(val, typ, jsToJSONProps);
+}
+
+function l(typ: any) {
+    return { literal: typ };
+}
+
+function a(typ: any) {
+    return { arrayItems: typ };
+}
+
+function i(typ: any) {
+    return { integer: typ };
+}
+
+function p(pattern: any) {
+    return { pattern };
+}
+
+function s(typ: any, min: any, max: any) {
+    return { string: typ, min, max };
+}
+
+function n(typ: any, min: any, max: any) {
+    return { number: typ, min, max };
+}
+
+function u(...typs: any[]) {
+    return { unionMembers: typs };
+}
+
+function o(props: any[], additional: any) {
+    return { props, additional };
+}
+
+function m(additional: any) {
+    const props: any[] = [];
+    return { props, additional };
+}
+
+function r(name: string) {
+    return { ref: name };
+}
+
+const typeMap: any = {
+    "TopLevel": o([
+        { json: "hashCode", js: "hashCode", typ: "" },
+        { json: "noSuchMethod", js: "noSuchMethod", typ: "" },
+        { json: "runtimeType", js: "runtimeType", typ: i(0) },
+        { json: "toString", js: "toString", typ: true },
+    ], false),
+};
diff --git a/head/typescript-effect-schema/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts b/head/typescript-effect-schema/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
new file mode 100644
index 0000000..23752f5
--- /dev/null
+++ b/head/typescript-effect-schema/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
@@ -0,0 +1,9 @@
+import * as S from "effect/Schema";
+
+
+export class TopLevel extends S.Class<TopLevel>("TopLevel")({
+    "hashCode": S.String,
+    "noSuchMethod": S.String,
+    "runtimeType": S.Int,
+    "toString": S.Boolean,
+}) {}
diff --git a/head/typescript-zod/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts b/head/typescript-zod/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
new file mode 100644
index 0000000..3097761
--- /dev/null
+++ b/head/typescript-zod/test/inputs/json/samples/dart-object-members.json/default/TopLevel.ts
@@ -0,0 +1,10 @@
+import * as z from "zod";
+
+
+export const TopLevelSchema = z.object({
+    "hashCode": z.string(),
+    "noSuchMethod": z.string(),
+    "runtimeType": z.number().int(),
+    "toString": z.boolean(),
+});
+export type TopLevel = z.infer<typeof TopLevelSchema>;
