From 83d212fe0f837708c2f3b2a1ba24ed596cc5415b Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Mon, 6 Mar 2023 00:12:11 +0100
Subject: [PATCH] Use SFINAE to avoid conflicts between visit functions

---
 components/esm/esmbridge.hpp | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/components/esm/esmbridge.hpp b/components/esm/esmbridge.hpp
index 8810e30594..ee6238cbc6 100644
--- a/components/esm/esmbridge.hpp
+++ b/components/esm/esmbridge.hpp
@@ -18,6 +18,15 @@ namespace ESM
     struct CellId;
     class RefId;
 
+    class CellVariant;
+
+    template <class, class T>
+    using Substitute = T;
+
+    template <class F, class... T>
+    using VisitReturnType = std::enable_if_t<(std::is_base_of_v<CellVariant, std::decay_t<T>> && ...),
+        typename std::invoke_result<F, Substitute<T, const Cell&>...>::type>;
+
     class CellVariant
     {
     protected:
@@ -39,7 +48,7 @@ namespace ESM
         const ESM::Cell& getEsm3() const;
 
         template <class F, class... T>
-        friend auto visit(F&& f, T&&... v);
+        friend VisitReturnType<F, T...> visit(F&& f, T&&... v);
     };
 
     struct ReferenceVariant
@@ -66,7 +75,7 @@ namespace ESM
     };
 
     template <class F, class... T>
-    auto visit(F&& f, T&&... v)
+    VisitReturnType<F, T...> visit(F&& f, T&&... v)
     {
         return std::visit([&](auto*... ptr) { return std::forward<F>(f)(*ptr...); }, std::forward<T>(v).mVariant...);
     }