From c6c224a78715d5e2c532fe318325fbca8e70e701 Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Fri, 9 Dec 2022 20:00:08 +0300
Subject: Add noexcept to move constructors and move assignment operators

---
 libbutl/optional.hxx | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

(limited to 'libbutl/optional.hxx')

diff --git a/libbutl/optional.hxx b/libbutl/optional.hxx
index 7d66ac5..f22189b 100644
--- a/libbutl/optional.hxx
+++ b/libbutl/optional.hxx
@@ -108,10 +108,16 @@ namespace butl
 #if (!defined(_MSC_VER) || _MSC_VER > 1900) &&  \
     (!defined(__GNUC__) || __GNUC__ > 4 || defined(__clang__))
       constexpr optional_data (const optional_data& o): v_ (o.v_) {if (v_) new (&d_) T (o.d_);}
-      constexpr optional_data (optional_data&& o):      v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
+
+      constexpr optional_data (optional_data&& o)
+        noexcept (std::is_nothrow_move_constructible<T>::value)
+        : v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
 #else
       optional_data (const optional_data& o): v_ (o.v_) {if (v_) new (&d_) T (o.d_);}
-      optional_data (optional_data&& o):      v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
+
+      optional_data (optional_data&& o)
+        noexcept (std::is_nothrow_move_constructible<T>::value)
+        : v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
 #endif
 
       optional_data& operator= (nullopt_t);
@@ -119,7 +125,11 @@ namespace butl
       optional_data& operator= (T&&);
 
       optional_data& operator= (const optional_data&);
-      optional_data& operator= (optional_data&&);
+
+      optional_data& operator= (optional_data&&)
+        noexcept (std::is_nothrow_move_constructible<T>::value &&
+                  std::is_nothrow_move_assignable<T>::value    &&
+                  std::is_nothrow_destructible<T>::value);
 
       ~optional_data ();
     };
@@ -151,10 +161,16 @@ namespace butl
 #if (!defined(_MSC_VER) || _MSC_VER > 1900) && \
     (!defined(__GNUC__) || __GNUC__ > 4 || defined(__clang__))
       constexpr optional_data (const optional_data& o): v_ (o.v_) {if (v_) new (&d_) T (o.d_);}
-      constexpr optional_data (optional_data&& o):      v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
+
+      constexpr optional_data (optional_data&& o)
+        noexcept (std::is_nothrow_move_constructible<T>::value)
+        : v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
 #else
       optional_data (const optional_data& o): v_ (o.v_) {if (v_) new (&d_) T (o.d_);}
-      optional_data (optional_data&& o):      v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
+
+      optional_data (optional_data&& o)
+        noexcept (std::is_nothrow_move_constructible<T>::value)
+        : v_ (o.v_) {if (v_) new (&d_) T (std::move (o.d_));}
 #endif
 
       optional_data& operator= (nullopt_t);
@@ -162,7 +178,12 @@ namespace butl
       optional_data& operator= (T&&);
 
       optional_data& operator= (const optional_data&);
-      optional_data& operator= (optional_data&&);
+
+      // Note: it is trivially destructible and thus is no-throw destructible.
+      //
+      optional_data& operator= (optional_data&&)
+        noexcept (std::is_nothrow_move_constructible<T>::value &&
+                  std::is_nothrow_move_assignable<T>::value);
     };
 
     template <typename T,
-- 
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