From 8dbbf7417cd5445287441ffbba3730f992616863 Mon Sep 17 00:00:00 2001
From: BlackMATov <blackmat@mail.ru>
Date: Sun, 12 Feb 2023 02:39:25 +0700
Subject: [PATCH] reduce some boilerplate

---
 develop/singles/headers/meta.hpp/meta_all.hpp | 154 +++++-------------
 .../meta_detail/value_utilities/uarg.hpp      |   4 +-
 .../meta_detail/value_utilities/uinst.hpp     |   4 +-
 headers/meta.hpp/meta_invoke/invoke.hpp       |  52 ++----
 headers/meta.hpp/meta_states/constructor.hpp  |  40 ++---
 headers/meta.hpp/meta_states/function.hpp     |  30 +---
 headers/meta.hpp/meta_states/method.hpp       |  24 +--
 7 files changed, 90 insertions(+), 218 deletions(-)

diff --git a/develop/singles/headers/meta.hpp/meta_all.hpp b/develop/singles/headers/meta.hpp/meta_all.hpp
index 9ff6491..803e301 100644
--- a/develop/singles/headers/meta.hpp/meta_all.hpp
+++ b/develop/singles/headers/meta.hpp/meta_all.hpp
@@ -5228,7 +5228,7 @@ namespace meta_hpp::detail
         };
 
     public:
-        uarg_base() = delete;
+        uarg_base() = default;
         ~uarg_base() = default;
 
         uarg_base(uarg_base&&) = default;
@@ -5298,7 +5298,7 @@ namespace meta_hpp::detail
 {
     class uarg final : public uarg_base {
     public:
-        uarg() = delete;
+        uarg() = default;
         ~uarg() = default;
 
         uarg(uarg&&) = default;
@@ -5719,13 +5719,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue function::invoke(Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->invoke(vargs);
-        } else {
-            return state_->invoke({});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->invoke(vargs);
     }
 
     template < typename... Args >
@@ -5743,24 +5739,16 @@ namespace meta_hpp
 
     template < typename... Args >
     bool function::is_invocable_with() const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vargs);
     }
 
     template < typename... Args >
     bool function::is_invocable_with(Args&&... args) const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vargs);
     }
 
     inline argument function::get_argument(std::size_t position) const noexcept {
@@ -5784,7 +5772,7 @@ namespace meta_hpp::detail
         };
 
     public:
-        uinst_base() = delete;
+        uinst_base() = default;
         ~uinst_base() = default;
 
         uinst_base(uinst_base&&) = default;
@@ -5859,7 +5847,7 @@ namespace meta_hpp::detail
 {
     class uinst final : public uinst_base {
     public:
-        uinst() = delete;
+        uinst() = default;
         ~uinst() = default;
 
         uinst(uinst&&) = default;
@@ -6464,12 +6452,8 @@ namespace meta_hpp
     uvalue method::invoke(Instance&& instance, Args&&... args) const {
         using namespace detail;
         const uinst vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->invoke(vinst, vargs);
-        } else {
-            return state_->invoke(vinst, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->invoke(vinst, vargs);
     }
 
     template < typename Instance, typename... Args >
@@ -6489,24 +6473,16 @@ namespace meta_hpp
     bool method::is_invocable_with() const noexcept {
         using namespace detail;
         const uinst_base vinst{type_list<Instance>{}};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vinst, vargs);
-        } else {
-            return state_->is_invocable_with(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vinst, vargs);
     }
 
     template < typename Instance, typename... Args >
     bool method::is_invocable_with(Instance&& instance, Args&&... args) const noexcept {
         using namespace detail;
         const uinst_base vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vinst, vargs);
-        } else {
-            return state_->is_invocable_with(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vinst, vargs);
     }
 
     inline argument method::get_argument(std::size_t position) const noexcept {
@@ -6528,12 +6504,8 @@ namespace meta_hpp
     template < detail::function_pointer_kind Function, typename... Args >
     uvalue invoke(Function function_ptr, Args&&... args) {
         using namespace detail;
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return raw_function_invoke<function_policy::as_copy_t>(function_ptr, vargs);
-        } else {
-            return raw_function_invoke<function_policy::as_copy_t>(function_ptr, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return raw_function_invoke<function_policy::as_copy_t>(function_ptr, vargs);
     }
 }
 
@@ -6563,12 +6535,8 @@ namespace meta_hpp
     uvalue invoke(Method method_ptr, Instance&& instance, Args&&... args) {
         using namespace detail;
         const uinst vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, vargs);
-        } else {
-            return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, vargs);
     }
 }
 
@@ -6586,24 +6554,16 @@ namespace meta_hpp
 
     template < detail::function_pointer_kind Function, typename... Args >
     bool is_invocable_with() {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return raw_function_is_invocable_with<Function>(vargs);
-        } else {
-            return raw_function_is_invocable_with<Function>({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return raw_function_is_invocable_with<Function>(vargs);
     }
 
     template < detail::function_pointer_kind Function, typename... Args >
     bool is_invocable_with(Args&&... args) {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return raw_function_is_invocable_with<Function>(vargs);
-        } else {
-            return raw_function_is_invocable_with<Function>({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return raw_function_is_invocable_with<Function>(vargs);
     }
 }
 
@@ -6650,24 +6610,16 @@ namespace meta_hpp
     bool is_invocable_with() {
         using namespace detail;
         const uinst_base vinst{type_list<Instance>{}};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return raw_method_is_invocable_with<Method>(vinst, vargs);
-        } else {
-            return raw_method_is_invocable_with<Method>(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return raw_method_is_invocable_with<Method>(vinst, vargs);
     }
 
     template < detail::method_pointer_kind Method, typename Instance, typename... Args >
     bool is_invocable_with(Instance&& instance, Args&&... args) {
         using namespace detail;
         const uinst_base vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return raw_method_is_invocable_with<Method>(vinst, vargs);
-        } else {
-            return raw_method_is_invocable_with<Method>(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return raw_method_is_invocable_with<Method>(vinst, vargs);
     }
 }
 
@@ -6888,13 +6840,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue constructor::create(Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->create(vargs);
-        } else {
-            return state_->create({});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->create(vargs);
     }
 
     template < typename... Args >
@@ -6907,13 +6855,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue constructor::create_at(void* mem, Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->create_at(mem, vargs);
-        } else {
-            return state_->create_at(mem, {});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->create_at(mem, vargs);
     }
 
     template < typename... Args >
@@ -6926,24 +6870,16 @@ namespace meta_hpp
 
     template < typename... Args >
     bool constructor::is_invocable_with() const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vargs);
     }
 
     template < typename... Args >
     bool constructor::is_invocable_with(Args&&... args) const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vargs);
     }
 
     inline argument constructor::get_argument(std::size_t position) const noexcept {
diff --git a/headers/meta.hpp/meta_detail/value_utilities/uarg.hpp b/headers/meta.hpp/meta_detail/value_utilities/uarg.hpp
index c68a889..f800339 100644
--- a/headers/meta.hpp/meta_detail/value_utilities/uarg.hpp
+++ b/headers/meta.hpp/meta_detail/value_utilities/uarg.hpp
@@ -24,7 +24,7 @@ namespace meta_hpp::detail
         };
 
     public:
-        uarg_base() = delete;
+        uarg_base() = default;
         ~uarg_base() = default;
 
         uarg_base(uarg_base&&) = default;
@@ -94,7 +94,7 @@ namespace meta_hpp::detail
 {
     class uarg final : public uarg_base {
     public:
-        uarg() = delete;
+        uarg() = default;
         ~uarg() = default;
 
         uarg(uarg&&) = default;
diff --git a/headers/meta.hpp/meta_detail/value_utilities/uinst.hpp b/headers/meta.hpp/meta_detail/value_utilities/uinst.hpp
index 10a8b92..b802d2d 100644
--- a/headers/meta.hpp/meta_detail/value_utilities/uinst.hpp
+++ b/headers/meta.hpp/meta_detail/value_utilities/uinst.hpp
@@ -24,7 +24,7 @@ namespace meta_hpp::detail
         };
 
     public:
-        uinst_base() = delete;
+        uinst_base() = default;
         ~uinst_base() = default;
 
         uinst_base(uinst_base&&) = default;
@@ -99,7 +99,7 @@ namespace meta_hpp::detail
 {
     class uinst final : public uinst_base {
     public:
-        uinst() = delete;
+        uinst() = default;
         ~uinst() = default;
 
         uinst(uinst&&) = default;
diff --git a/headers/meta.hpp/meta_invoke/invoke.hpp b/headers/meta.hpp/meta_invoke/invoke.hpp
index 2eb035b..73b4e91 100644
--- a/headers/meta.hpp/meta_invoke/invoke.hpp
+++ b/headers/meta.hpp/meta_invoke/invoke.hpp
@@ -27,12 +27,8 @@ namespace meta_hpp
     template < detail::function_pointer_kind Function, typename... Args >
     uvalue invoke(Function function_ptr, Args&&... args) {
         using namespace detail;
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return raw_function_invoke<function_policy::as_copy_t>(function_ptr, vargs);
-        } else {
-            return raw_function_invoke<function_policy::as_copy_t>(function_ptr, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return raw_function_invoke<function_policy::as_copy_t>(function_ptr, vargs);
     }
 }
 
@@ -62,12 +58,8 @@ namespace meta_hpp
     uvalue invoke(Method method_ptr, Instance&& instance, Args&&... args) {
         using namespace detail;
         const uinst vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, vargs);
-        } else {
-            return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return raw_method_invoke<method_policy::as_copy_t>(method_ptr, vinst, vargs);
     }
 }
 
@@ -85,24 +77,16 @@ namespace meta_hpp
 
     template < detail::function_pointer_kind Function, typename... Args >
     bool is_invocable_with() {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return raw_function_is_invocable_with<Function>(vargs);
-        } else {
-            return raw_function_is_invocable_with<Function>({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return raw_function_is_invocable_with<Function>(vargs);
     }
 
     template < detail::function_pointer_kind Function, typename... Args >
     bool is_invocable_with(Args&&... args) {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return raw_function_is_invocable_with<Function>(vargs);
-        } else {
-            return raw_function_is_invocable_with<Function>({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return raw_function_is_invocable_with<Function>(vargs);
     }
 }
 
@@ -149,23 +133,15 @@ namespace meta_hpp
     bool is_invocable_with() {
         using namespace detail;
         const uinst_base vinst{type_list<Instance>{}};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return raw_method_is_invocable_with<Method>(vinst, vargs);
-        } else {
-            return raw_method_is_invocable_with<Method>(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return raw_method_is_invocable_with<Method>(vinst, vargs);
     }
 
     template < detail::method_pointer_kind Method, typename Instance, typename... Args >
     bool is_invocable_with(Instance&& instance, Args&&... args) {
         using namespace detail;
         const uinst_base vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return raw_method_is_invocable_with<Method>(vinst, vargs);
-        } else {
-            return raw_method_is_invocable_with<Method>(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return raw_method_is_invocable_with<Method>(vinst, vargs);
     }
 }
diff --git a/headers/meta.hpp/meta_states/constructor.hpp b/headers/meta.hpp/meta_states/constructor.hpp
index 856c48b..113dfc2 100644
--- a/headers/meta.hpp/meta_states/constructor.hpp
+++ b/headers/meta.hpp/meta_states/constructor.hpp
@@ -165,13 +165,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue constructor::create(Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->create(vargs);
-        } else {
-            return state_->create({});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->create(vargs);
     }
 
     template < typename... Args >
@@ -184,13 +180,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue constructor::create_at(void* mem, Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->create_at(mem, vargs);
-        } else {
-            return state_->create_at(mem, {});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->create_at(mem, vargs);
     }
 
     template < typename... Args >
@@ -203,24 +195,16 @@ namespace meta_hpp
 
     template < typename... Args >
     bool constructor::is_invocable_with() const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vargs);
     }
 
     template < typename... Args >
     bool constructor::is_invocable_with(Args&&... args) const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vargs);
     }
 
     inline argument constructor::get_argument(std::size_t position) const noexcept {
diff --git a/headers/meta.hpp/meta_states/function.hpp b/headers/meta.hpp/meta_states/function.hpp
index 59cd7fc..a75529b 100644
--- a/headers/meta.hpp/meta_states/function.hpp
+++ b/headers/meta.hpp/meta_states/function.hpp
@@ -144,13 +144,9 @@ namespace meta_hpp
 
     template < typename... Args >
     uvalue function::invoke(Args&&... args) const {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->invoke(vargs);
-        } else {
-            return state_->invoke({});
-        }
+        using namespace detail;
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->invoke(vargs);
     }
 
     template < typename... Args >
@@ -168,24 +164,16 @@ namespace meta_hpp
 
     template < typename... Args >
     bool function::is_invocable_with() const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vargs);
     }
 
     template < typename... Args >
     bool function::is_invocable_with(Args&&... args) const noexcept {
-        if constexpr ( sizeof...(Args) > 0 ) {
-            using namespace detail;
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vargs);
-        } else {
-            return state_->is_invocable_with({});
-        }
+        using namespace detail;
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vargs);
     }
 
     inline argument function::get_argument(std::size_t position) const noexcept {
diff --git a/headers/meta.hpp/meta_states/method.hpp b/headers/meta.hpp/meta_states/method.hpp
index 94fa64c..12f0630 100644
--- a/headers/meta.hpp/meta_states/method.hpp
+++ b/headers/meta.hpp/meta_states/method.hpp
@@ -160,12 +160,8 @@ namespace meta_hpp
     uvalue method::invoke(Instance&& instance, Args&&... args) const {
         using namespace detail;
         const uinst vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
-            return state_->invoke(vinst, vargs);
-        } else {
-            return state_->invoke(vinst, {});
-        }
+        const std::array<uarg, sizeof...(Args)> vargs{uarg{std::forward<Args>(args)}...};
+        return state_->invoke(vinst, vargs);
     }
 
     template < typename Instance, typename... Args >
@@ -185,24 +181,16 @@ namespace meta_hpp
     bool method::is_invocable_with() const noexcept {
         using namespace detail;
         const uinst_base vinst{type_list<Instance>{}};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
-            return state_->is_invocable_with(vinst, vargs);
-        } else {
-            return state_->is_invocable_with(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{type_list<Args>{}}...};
+        return state_->is_invocable_with(vinst, vargs);
     }
 
     template < typename Instance, typename... Args >
     bool method::is_invocable_with(Instance&& instance, Args&&... args) const noexcept {
         using namespace detail;
         const uinst_base vinst{std::forward<Instance>(instance)};
-        if constexpr ( sizeof...(Args) > 0 ) {
-            const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
-            return state_->is_invocable_with(vinst, vargs);
-        } else {
-            return state_->is_invocable_with(vinst, {});
-        }
+        const std::array<uarg_base, sizeof...(Args)> vargs{uarg_base{std::forward<Args>(args)}...};
+        return state_->is_invocable_with(vinst, vargs);
     }
 
     inline argument method::get_argument(std::size_t position) const noexcept {