From 0534572646dceeb3949d8037c57e1a1916f8257a Mon Sep 17 00:00:00 2001
From: ulic-youthlic <ulic.youthlic@gmail.com>
Date: Mon, 28 Apr 2025 13:58:27 +0800
Subject: [PATCH] add requires for function

---
 main.cxx | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/main.cxx b/main.cxx
index 358ccec..540e1f8 100644
--- a/main.cxx
+++ b/main.cxx
@@ -8,7 +8,11 @@ struct BuildMixin {};
 
 template <>
 struct BuildMixin<true> {
-  auto build(this auto&& self) { return self.p1 + self.p2; }
+  auto build(this auto&& self)
+    requires requires { self.p1 + self.p2; }
+  {
+    return self.p1 + self.p2;
+  }
 };
 
 template <bool enabled>
@@ -16,7 +20,9 @@ struct Param1Mixin {};
 
 template <>
 struct Param1Mixin<false> {
-  auto fill_param1(this auto&& self) {
+  auto fill_param1(this auto&& self)
+    requires requires { self.p1; }
+  {
     self.p1 = 1;
     return Builder<true, std::remove_reference_t<decltype(self)>::param2_v>(
         self);
@@ -28,7 +34,9 @@ struct Param2Mixin {};
 
 template <>
 struct Param2Mixin<false> {
-  auto fill_param2(this auto&& self) {
+  auto fill_param2(this auto&& self)
+    requires requires { self.p2; }
+  {
     self.p2 = 1;
     return Builder<std::remove_reference_t<decltype(self)>::param1_v, true>(
         self);