From 1ccb808a186d4dd8ac817170a80ce62301a11125 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Lie=CC=81tar?= <paul@lietar.net>
Date: Fri, 10 Apr 2020 12:36:36 +0200
Subject: [PATCH] Fix clang-tidy warning and CR comments.

---
 src/ds/helpers.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/ds/helpers.h b/src/ds/helpers.h
index 979c4b6..00159f8 100644
--- a/src/ds/helpers.h
+++ b/src/ds/helpers.h
@@ -108,7 +108,7 @@ namespace snmalloc
    * allocation. This is useful in the allocator code paths, where we can't
    * safely use std::function.
    *
-   * Inspired off the C++ proposal:
+   * Inspired by the C++ proposal:
    * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0792r2.html
    */
   template<typename Fn>
@@ -116,12 +116,17 @@ namespace snmalloc
   template<typename R, typename... Args>
   struct function_ref<R(Args...)>
   {
-    template<typename Fn>
-    function_ref(Fn&& fn)
+    // The enable_if is used to stop this constructor from shadowing the default
+    // copy / move constructors.
+    template<
+      typename Fn,
+      typename = std::enable_if_t<
+        !std::is_same_v<std::decay_t<Fn>, function_ref>> function_ref(Fn&& fn)
     {
       data_ = static_cast<void*>(&fn);
       fn_ = execute<Fn>;
     }
+
     R operator()(Args... args) const
     {
       return fn_(data_, args...);