From 653cb61d553605262bea9d5c1104befb980b97db Mon Sep 17 00:00:00 2001
From: Nana Sakisaka <1901813+saki7@users.noreply.github.com>
Date: Mon, 14 Sep 2026 00:14:05 +0900
Subject: [PATCH] Refactor some facilities

---
 include/iris/x4/attribute/as.hpp   |  3 +--
 include/iris/x4/core/action.hpp    |  4 ++--
 include/iris/x4/directive/with.hpp | 16 ++++++++++++++--
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/include/iris/x4/attribute/as.hpp b/include/iris/x4/attribute/as.hpp
index 6ddc50f7c..8c9aa32b3 100644
--- a/include/iris/x4/attribute/as.hpp
+++ b/include/iris/x4/attribute/as.hpp
@@ -104,8 +104,7 @@ struct as_type_parser : unary_parser<Subject, as_type_parser<T, Subject>>
     // `outer_parser<U>(as<T>(subject))` forwards temporary `T` local variable for the subject, then move the variable to `U&`
     template<std::forward_iterator It, std::sentinel_for<It> Se, class Context, X4NonUnusedAttribute OuterAttr>
         requires
-            (!std::same_as<std::remove_const_t<OuterAttr>, T>) &&
-            X4Movable<T, OuterAttr>
+            (!std::same_as<std::remove_const_t<OuterAttr>, T>)
     [[nodiscard]] constexpr bool
     parse(It& first, Se const& last, Context const& ctx, OuterAttr& outer_attr) const
         noexcept(
diff --git a/include/iris/x4/core/action.hpp b/include/iris/x4/core/action.hpp
index b3b70234b..6341b4a0d 100644
--- a/include/iris/x4/core/action.hpp
+++ b/include/iris/x4/core/action.hpp
@@ -94,7 +94,7 @@ struct action : proxy_parser<Subject, action<Subject, ActionF>>
             noexcept(this->parse_main(first, last, ctx, std::declval<typename base_type::attribute_type&>()))
         )
     {
-        typename base_type::attribute_type attr_temp; // default-initialize
+        typename base_type::attribute_type attr_temp{}; // value-initialize
         return this->parse_main(first, last, ctx, attr_temp);
     }
 
@@ -138,7 +138,7 @@ struct action : proxy_parser<Subject, action<Subject, ActionF>>
             noexcept(this->parse_main(first, last, ctx, std::declval<typename base_type::attribute_type&>()))
         )
     {
-        typename base_type::attribute_type attr_temp; // default-initialize
+        typename base_type::attribute_type attr_temp{}; // value-initialize
         return this->parse_main(first, last, ctx, attr_temp);
     }
 
diff --git a/include/iris/x4/directive/with.hpp b/include/iris/x4/directive/with.hpp
index 236b24436..b658d82e4 100644
--- a/include/iris/x4/directive/with.hpp
+++ b/include/iris/x4/directive/with.hpp
@@ -233,6 +233,8 @@ using parsers::directive::with;
 template<class Subject, class... IDs>
 struct without_directive : proxy_parser<Subject, without_directive<Subject, IDs...>>
 {
+    static_assert(sizeof...(IDs) > 0);
+
     template<std::forward_iterator It, std::sentinel_for<It> Se, class Context, X4Attribute Attr>
     [[nodiscard]] constexpr bool
     parse(It& first, Se const& last, Context const& ctx, Attr& attr) const
@@ -258,9 +260,19 @@ namespace detail {
 template<class... IDs>
 struct without_gen
 {
+    // `without<>(p)` is no-op
+    template<class Subject>
+        requires (sizeof...(IDs) == 0)
+    [[nodiscard]] static constexpr auto&&
+    operator[](Subject&& subject IRIS_LIFETIMEBOUND) noexcept
+    {
+        return static_cast<Subject&&>(subject);
+    }
+
     template<class Subject>
-    [[nodiscard]] constexpr without_directive<std::remove_cvref_t<Subject>, IDs...>
-    operator[](Subject&& subject) const // TODO: MSVC 2022 does not properly handle static operator[]
+        requires (sizeof...(IDs) > 0)
+    [[nodiscard]] static constexpr without_directive<std::remove_cvref_t<Subject>, IDs...>
+    operator[](Subject&& subject)
         noexcept(std::is_nothrow_constructible_v<without_directive<std::remove_cvref_t<Subject>, IDs...>, Subject>)
     {
         return without_directive<std::remove_cvref_t<Subject>, IDs...>{