diff --git a/include/mp/proxy-types.h b/include/mp/proxy-types.h
index 410de123..0221784c 100644
--- a/include/mp/proxy-types.h
+++ b/include/mp/proxy-types.h
@@ -38,15 +38,14 @@ struct StructField
     Struct& m_struct;
 
     // clang-format off
-    template<typename A = Accessor> auto get() const -> AUTO_RETURN(A::get(this->m_struct))
+    template<typename A = Accessor> auto get() const -> decltype(A::get(this->m_struct)) { return A::get(this->m_struct); }
     template<typename A = Accessor> auto has() const -> typename std::enable_if<A::optional, bool>::type { return A::getHas(m_struct); }
     template<typename A = Accessor> auto has() const -> typename std::enable_if<!A::optional && A::boxed, bool>::type { return A::has(m_struct); }
     template<typename A = Accessor> auto has() const -> typename std::enable_if<!A::optional && !A::boxed, bool>::type { return true; }
     template<typename A = Accessor> auto want() const -> typename std::enable_if<A::requested, bool>::type { return A::getWant(m_struct); }
     template<typename A = Accessor> auto want() const -> typename std::enable_if<!A::requested, bool>::type { return true; }
-
-    template<typename A = Accessor, typename... Args> auto set(Args&&... args) const -> AUTO_RETURN(A::set(this->m_struct, std::forward<Args>(args)...))
-    template<typename A = Accessor, typename... Args> auto init(Args&&... args) const -> AUTO_RETURN(A::init(this->m_struct, std::forward<Args>(args)...))
+    template<typename A = Accessor, typename... Args> decltype(auto) set(Args&&... args) const { return A::set(this->m_struct, std::forward<Args>(args)...); }
+    template<typename A = Accessor, typename... Args> decltype(auto) init(Args&&... args) const { return A::init(this->m_struct, std::forward<Args>(args)...); }
     template<typename A = Accessor> auto setHas() const -> typename std::enable_if<A::optional>::type { return A::setHas(m_struct); }
     template<typename A = Accessor> auto setHas() const -> typename std::enable_if<!A::optional>::type { }
     template<typename A = Accessor> auto setWant() const -> typename std::enable_if<A::requested>::type { return A::setWant(m_struct); }
@@ -59,7 +58,7 @@ void CustomBuildField(TypeList<>,
     Priority<1>,
     ClientInvokeContext& invoke_context,
     Output&& output,
-    typename std::enable_if<std::is_same<decltype(output.init()), Context::Builder>::value>::type* enable = nullptr)
+    typename std::enable_if<std::is_same<decltype(output.get()), Context::Builder>::value>::type* enable = nullptr)
 {
     auto& connection = invoke_context.connection;
     auto& thread_context = invoke_context.thread_context;
@@ -106,8 +105,10 @@ kj::Promise<U> JoinPromises(kj::Promise<T>&& prom1, kj::Promise<U>&& prom2)
     return prom1.then(kj::mvCapture(prom2, [](kj::Promise<U> prom2) { return prom2; }));
 }
 
+//! PassField override for mp.Context arguments. Return asynchronously and call
+//! function on other thread found in context.
 template <typename Accessor, typename ServerContext, typename Fn, typename... Args>
-auto PassField(TypeList<>, ServerContext& server_context, const Fn& fn, const Args&... args) ->
+auto PassField(Priority<1>, TypeList<>, ServerContext& server_context, const Fn& fn, Args&&... args) ->
     typename std::enable_if<
         std::is_same<decltype(Accessor::get(server_context.call_context.getParams())), Context::Reader>::value,
         kj::Promise<typename ServerContext::CallContext>>::type
@@ -521,7 +522,7 @@ struct ProxyCallFn
     InvokeContext m_proxy;
 
     template <typename... CallParams>
-    auto operator()(CallParams&&... params) -> AUTO_RETURN(this->m_proxy->call(std::forward<CallParams>(params)...))
+    decltype(auto) operator()(CallParams&&... params) { return this->m_proxy->call(std::forward<CallParams>(params)...); }
 };
 
 template <typename FnR, typename... FnParams, typename Input, typename ReadDest>
@@ -762,10 +763,10 @@ struct ListOutput<::capnp::List<T, kind>>
     size_t m_index;
 
     // clang-format off
-    auto get() const -> AUTO_RETURN(this->m_builder[this->m_index])
-    auto init() const -> AUTO_RETURN(this->m_builder[this->m_index])
-    template<typename B = Builder, typename Arg> auto set(Arg&& arg) const -> AUTO_RETURN(static_cast<B&>(this->m_builder).set(m_index, std::forward<Arg>(arg)))
-    template<typename B = Builder, typename Arg> auto init(Arg&& arg) const -> AUTO_RETURN(static_cast<B&>(this->m_builder).init(m_index, std::forward<Arg>(arg)))
+    decltype(auto) get() const { return this->m_builder[this->m_index]; }
+    decltype(auto) init() const { return this->m_builder[this->m_index]; }
+    template<typename B = Builder, typename Arg> decltype(auto) set(Arg&& arg) const { return static_cast<B&>(this->m_builder).set(m_index, std::forward<Arg>(arg)); }
+    template<typename B = Builder, typename Arg> decltype(auto) init(Arg&& arg) const { return static_cast<B&>(this->m_builder).init(m_index, std::forward<Arg>(arg)); }
     // clang-format on
 };
 
@@ -978,8 +979,9 @@ void CustomBuildField(TypeList<LocalType> local_type,
     BuildOne<0>(local_type, invoke_context, output.init(), value);
 }
 
+//! PassField override for C++ pointer arguments.
 template <typename Accessor, typename LocalType, typename ServerContext, typename Fn, typename... Args>
-void PassField(TypeList<LocalType*>, ServerContext& server_context, const Fn& fn, Args&&... args)
+void PassField(Priority<1>, TypeList<LocalType*>, ServerContext& server_context, const Fn& fn, Args&&... args)
 {
     const auto& params = server_context.call_context.getParams();
     const auto& input = Make<StructField, Accessor>(params);
@@ -1002,8 +1004,9 @@ void PassField(TypeList<LocalType*>, ServerContext& server_context, const Fn& fn
         Make<StructField, Accessor>(results), param);
 }
 
+//! PassField override for callable interface reference arguments.
 template <typename Accessor, typename LocalType, typename ServerContext, typename Fn, typename... Args>
-auto PassField(TypeList<LocalType&>, ServerContext& server_context, Fn&& fn, Args&&... args)
+auto PassField(Priority<1>, TypeList<LocalType&>, ServerContext& server_context, Fn&& fn, Args&&... args)
     -> Require<typename decltype(Accessor::get(server_context.call_context.getParams()))::Calls>
 {
     // Just create a temporary ProxyClient if argument is a reference to an
@@ -1051,8 +1054,9 @@ void MaybeSetWant(LocalTypes, Priority<0>, Args&&...)
 {
 }
 
+//! Default PassField implementation calling MaybeReadField/MaybeBuildField.
 template <typename Accessor, typename LocalType, typename ServerContext, typename Fn, typename... Args>
-void DefaultPassField(TypeList<LocalType>, ServerContext& server_context, Fn&& fn, Args&&... args)
+void PassField(Priority<0>, TypeList<LocalType>, ServerContext& server_context, Fn&& fn, Args&&... args)
 {
     InvokeContext& invoke_context = server_context;
     using ArgType = RemoveCvRef<LocalType>;
@@ -1074,6 +1078,18 @@ void DefaultPassField(TypeList<LocalType>, ServerContext& server_context, Fn&& f
         Make<StructField, Accessor>(results), *param);
 }
 
+//! Default PassField implementation for count(0) arguments, calling ReadField/BuildField
+template <typename Accessor, typename ServerContext, typename Fn, typename... Args>
+void PassField(Priority<0>, TypeList<>, ServerContext& server_context, const Fn& fn, Args&&... args)
+{
+    const auto& params = server_context.call_context.getParams();
+    const auto& input = Make<StructField, Accessor>(params);
+    ReadField(TypeList<>(), server_context, input);
+    fn.invoke(server_context, std::forward<Args>(args)...);
+    auto&& results = server_context.call_context.getResults();
+    BuildField(TypeList<>(), server_context, Make<StructField, Accessor>(results));
+}
+
 template <>
 struct ProxyServer<ThreadMap> final : public virtual ThreadMap::Server
 {
@@ -1103,18 +1119,6 @@ decltype(auto) CustomReadField(TypeList<>,
     invoke_context.connection.m_thread_map = input.get();
 }
 
-template <typename Accessor, typename ServerContext, typename Fn, typename... Args>
-auto PassField(TypeList<>, ServerContext& server_context, const Fn& fn, Args&&... args) -> typename std::enable_if<
-    std::is_same<decltype(Accessor::get(server_context.call_context.getParams())), ThreadMap::Client>::value>::type
-{
-    const auto& params = server_context.call_context.getParams();
-    const auto& input = Make<StructField, Accessor>(params);
-    ReadField(TypeList<>(), server_context, input);
-    fn.invoke(server_context, std::forward<Args>(args)...);
-    auto&& results = server_context.call_context.getResults();
-    BuildField(TypeList<>(), server_context, Make<StructField, Accessor>(results));
-}
-
 template <typename Derived, size_t N = 0>
 struct IterateFieldsHelper
 {
@@ -1248,10 +1252,12 @@ struct ServerCall
 {
     // FIXME: maybe call call_context.releaseParams()
     template <typename ServerContext, typename... Args>
-    auto invoke(ServerContext& server_context, TypeList<>, Args&&... args) const -> AUTO_RETURN(
-        ProxyServerMethodTraits<typename decltype(server_context.call_context.getParams())::Reads>::invoke(
+    decltype(auto) invoke(ServerContext& server_context, TypeList<>, Args&&... args) const
+    {
+        return ProxyServerMethodTraits<typename decltype(server_context.call_context.getParams())::Reads>::invoke(
             server_context,
-            std::forward<Args>(args)...))
+            std::forward<Args>(args)...);
+    }
 };
 
 struct ServerDestroy
@@ -1299,16 +1305,12 @@ struct ServerExcept : Parent
 template <class Accessor>
 void CustomPassField();
 
-// clang-format off
+//! PassField override calling CustomPassField function, if it exists.
 template <typename Accessor, typename... Args>
-auto CallPassField(Priority<2>, Args&&... args) -> AUTO_RETURN(CustomPassField<Accessor>(std::forward<Args>(args)...));
-
-template <typename Accessor, typename... Args>
-auto CallPassField(Priority<1>, Args&&... args) -> AUTO_RETURN(PassField<Accessor>(std::forward<Args>(args)...));
-
-template <typename Accessor, typename... Args>
-auto CallPassField(Priority<0>, Args&&... args) -> AUTO_RETURN(DefaultPassField<Accessor>(std::forward<Args>(args)...));
-// clang-format on
+auto PassField(Priority<2>, Args&&... args) -> decltype(CustomPassField<Accessor>(std::forward<Args>(args)...))
+{
+    return CustomPassField<Accessor>(std::forward<Args>(args)...);
+};
 
 template <int argc, typename Accessor, typename Parent>
 struct ServerField : Parent
@@ -1318,13 +1320,15 @@ struct ServerField : Parent
     const Parent& parent() const { return *this; }
 
     template <typename ServerContext, typename ArgTypes, typename... Args>
-    auto invoke(ServerContext& server_context, ArgTypes, Args&&... args) const
-        -> AUTO_RETURN(CallPassField<Accessor>(Priority<2>(),
+    decltype(auto) invoke(ServerContext& server_context, ArgTypes, Args&&... args) const
+    {
+        return PassField<Accessor>(Priority<2>(),
             typename Split<argc, ArgTypes>::First(),
             server_context,
             this->parent(),
             typename Split<argc, ArgTypes>::Second(),
-            std::forward<Args>(args)...))
+            std::forward<Args>(args)...);
+    }
 };
 
 template <int argc, typename Accessor, typename Parent>
diff --git a/include/mp/proxy.h b/include/mp/proxy.h
index 602c4ae4..6c0645e7 100644
--- a/include/mp/proxy.h
+++ b/include/mp/proxy.h
@@ -163,8 +163,10 @@ struct ProxyMethodTraits<MethodParams, Require<decltype(ProxyMethod<MethodParams
     : public FunctionTraits<decltype(ProxyMethod<MethodParams>::impl)>
 {
     template <typename ServerContext, typename... Args>
-    static auto invoke(ServerContext& server_context, Args&&... args) -> AUTO_RETURN(
-        (server_context.proxy_server.m_impl.get()->*ProxyMethod<MethodParams>::impl)(std::forward<Args>(args)...))
+    static decltype(auto) invoke(ServerContext& server_context, Args&&... args)
+    {
+        return (server_context.proxy_server.m_impl.get()->*ProxyMethod<MethodParams>::impl)(std::forward<Args>(args)...);
+    }
 };
 
 //! Customizable (through template specialization) traits class used in generated ProxyClient implementations from
diff --git a/include/mp/util.h b/include/mp/util.h
index 6addb018..ccbea6c9 100644
--- a/include/mp/util.h
+++ b/include/mp/util.h
@@ -55,17 +55,6 @@ namespace mp {
 //!        }
 //!     };
 
-// C++11 workaround for C++14 auto return functions
-// (http://en.cppreference.com/w/cpp/language/template_argument_deduction#auto-returning_functions)
-#define AUTO_DO_RETURN(pre, x) \
-    decltype(x)                \
-    {                          \
-        pre;                   \
-        return x;              \
-    }
-
-#define AUTO_RETURN(x) AUTO_DO_RETURN(, x)
-
 //! Type holding a list of types.
 //!
 //! Example:
@@ -102,7 +91,7 @@ struct ComposeFn
     Fn2&& fn2;
 
     template <typename... Args>
-    auto operator()(Args&&... args) -> AUTO_RETURN(this->fn1(this->fn2(std::forward<Args>(args)...)))
+    decltype(auto) operator()(Args&&... args) { return this->fn1(this->fn2(std::forward<Args>(args)...)); }
 };
 
 //! Bound function. See Bind() below.
@@ -116,8 +105,10 @@ struct BoundFn<Fn, TypeList<>, TypeList<BoundArgs...>>
     Fn&& m_fn;
 
     template <typename... FreeArgs>
-    auto operator()(BoundArgs&... bound_args, FreeArgs&&... free_args)
-        -> AUTO_RETURN(this->m_fn(bound_args..., std::forward<FreeArgs>(free_args)...))
+    decltype(auto) operator()(BoundArgs&... bound_args, FreeArgs&&... free_args)
+    {
+        return this->m_fn(bound_args..., std::forward<FreeArgs>(free_args)...);
+    }
 };
 
 //! Specialization of above for recursive case.
@@ -130,7 +121,7 @@ struct BoundFn<Fn, TypeList<BindArg, BindArgs...>, TypeList<BoundArgs...>>
 
     BoundFn(Fn& fn, BindArg& bind_arg, BindArgs&... bind_args) : Base{fn, bind_args...}, m_bind_arg(bind_arg) {}
 
-    // Use std::result_of instead of AUTO_RETURN to work around gcc bug
+    // Use std::result_of instead of decltype return to work around gcc bug
     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83249
     template <typename... FreeArgs>
     auto operator()(BoundArgs&... bound_args, FreeArgs&&... free_args) ->
@@ -167,7 +158,7 @@ struct BoundTupleFn
 {
     Fn& m_fn;
     template <typename... Params>
-    auto operator()(Params&&... params) -> AUTO_RETURN(this->m_fn(std::forward_as_tuple(params...)))
+    decltype(auto) operator()(Params&&... params) { return this->m_fn(std::forward_as_tuple(params...)); }
 };
 
 //! Bind tuple argument to function. Arguments passed to the returned function
diff --git a/src/mp/gen.cpp b/src/mp/gen.cpp
index 13071fba..c78d6ffa 100644
--- a/src/mp/gen.cpp
+++ b/src/mp/gen.cpp
@@ -240,12 +240,12 @@ void Generate(kj::StringPtr src_prefix,
         std::string cap = Cap(name);
         accessors << "struct " << cap << "\n";
         accessors << "{\n";
-        accessors << "    template<typename S> static auto get(S&& s) -> AUTO_RETURN(s.get" << cap << "())\n";
+        accessors << "    template<typename S> static auto get(S&& s) -> decltype(s.get" << cap << "()) { return s.get" << cap << "(); }\n";
         accessors << "    template<typename S> static bool has(S&& s) { return s.has" << cap << "(); }\n";
         accessors << "    template<typename S, typename A> static void set(S&& s, A&& a) { s.set" << cap
                   << "(std::forward<A>(a)); }\n";
-        accessors << "    template<typename S, typename... A> static auto init(S&& s, A&&... a) -> AUTO_RETURN(s.init"
-                  << cap << "(std::forward<A>(a)...))\n";
+        accessors << "    template<typename S, typename... A> static decltype(auto) init(S&& s, A&&... a) { return s.init"
+                  << cap << "(std::forward<A>(a)...); }\n";
         accessors << "    template<typename S> static bool getWant(S&& s) { return s.getWant" << cap << "(); }\n";
         accessors << "    template<typename S> static void setWant(S&& s) { s.setWant" << cap << "(true); }\n";
         accessors << "    template<typename S> static bool getHas(S&& s) { return s.getHas" << cap << "(); }\n";
@@ -317,8 +317,8 @@ void Generate(kj::StringPtr src_prefix,
                     auto field_name = field.getProto().getName();
                     auto member_name = field_name;
                     GetAnnotationText(field.getProto(), NAME_ANNOTATION_ID, &member_name);
-                    inl << "    static auto get(std::integral_constant<size_t, " << i << ">) -> AUTO_RETURN("
-                        << "&" << proxied_class_type << "::" << member_name << ")\n";
+                    inl << "    static decltype(auto) get(std::integral_constant<size_t, " << i << ">) { return "
+                        << "&" << proxied_class_type << "::" << member_name << "; }\n";
                     ++i;
                 }
                 inl << "    static constexpr size_t fields = " << i << ";\n";