From 0cbb9e221d0f80deaa9420b6b7a63ceae8058072 Mon Sep 17 00:00:00 2001
From: Herb Sutter <herb.sutter@gmail.com>
Date: Thu, 17 Dec 2020 11:36:23 -0800
Subject: [PATCH] Removed double `.load`

Require `chandler` to be never null by installing `[]()noexcept{}` as the handler if given a null pointer.
This lets us remove the double test in `assertion`.
---
 include/gsl/assert | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/gsl/assert b/include/gsl/assert
index 76e5344..9d0d3da 100644
--- a/include/gsl/assert
+++ b/include/gsl/assert
@@ -104,15 +104,16 @@ class contract_group {
 public:
     using handler = void (*)() noexcept;
 
-    contract_group(handler h)              : chandler{h} { }
-    auto set_handler(handler h) -> handler { return chandler.exchange(h); }
+    contract_group(handler h)              { set_handler(h); }
+    auto set_handler(handler h) -> handler { if (!h) h = []()noexcept{};
+                                             return chandler.exchange(h); }
     auto get_handler()          -> handler { return chandler; }
 
     auto expects(bool b) { assertion(b); }
     auto ensures(bool b) { assertion(b); }
 
 private:
-    auto assertion(bool b) { if (!b && chandler.load()) chandler.load()(); }
+    auto assertion(bool b) { if (!b) chandler.load()(); }
     std::atomic<handler> chandler;
 };