Make optional copy and move constructors constexpr

2 files changed, 21 insertions, 48 deletions

diff --git a/libbutl/optional.ixx b/libbutl/optional.ixx
index 2c40d30..18c0b0b 100644
--- a/libbutl/optional.ixx
+++ b/libbutl/optional.ixx
@@ -55,24 +55,6 @@ namespace butl
     }
 
     template <typename T>
-    inline optional_data<T, false>::
-    optional_data (const optional_data& o)
-        : v_ (o.v_)
-    {
-      if (v_)
-        new (&d_) T (o.d_);
-    }
-
-    template <typename T>
-    inline optional_data<T, false>::
-    optional_data (optional_data&& o)
-        : v_ (o.v_)
-    {
-      if (v_)
-        new (&d_) T (std::move (o.d_));
-    }
-
-    template <typename T>
     inline optional_data<T, false>& optional_data<T, false>::
     operator= (const optional_data& o)
     {
@@ -158,24 +140,6 @@ namespace butl
     }
 
     template <typename T>
-    inline optional_data<T, true>::
-    optional_data (const optional_data& o)
-        : v_ (o.v_)
-    {
-      if (v_)
-        new (&d_) T (o.d_);
-    }
-
-    template <typename T>
-    inline optional_data<T, true>::
-    optional_data (optional_data&& o)
-        : v_ (o.v_)
-    {
-      if (v_)
-        new (&d_) T (std::move (o.d_));
-    }
-
-    template <typename T>
     inline optional_data<T, true>& optional_data<T, true>::
     operator= (const optional_data& o)
     {
diff --git a/libbutl/optional.mxx b/libbutl/optional.mxx
index ae72399..9140432 100644
--- a/libbutl/optional.mxx
+++ b/libbutl/optional.mxx
@@ -57,20 +57,23 @@ LIBBUTL_MODEXPORT namespace butl
       constexpr optional_data (nullopt_t):  e_ (),              v_ (false) {}
       constexpr optional_data (const T& v): d_ (v),             v_ (true)  {}
       constexpr optional_data (T&& v):      d_ (std::move (v)), v_ (true)  {}
+
+      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_));}
 #else
       optional_data ():           e_ (),              v_ (false) {}
       optional_data (nullopt_t):  e_ (),              v_ (false) {}
       optional_data (const T& v): d_ (v),             v_ (true)  {}
       optional_data (T&& v):      d_ (std::move (v)), v_ (true)  {}
+
+      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_));}
 #endif
 
       optional_data& operator= (nullopt_t);
       optional_data& operator= (const T&);
       optional_data& operator= (T&&);
 
-      optional_data (const optional_data&);
-      optional_data (optional_data&&);
-
       optional_data& operator= (const optional_data&);
       optional_data& operator= (optional_data&&);
 
@@ -94,20 +97,23 @@ LIBBUTL_MODEXPORT namespace butl
       constexpr optional_data (nullopt_t):  e_ (),              v_ (false) {}
       constexpr optional_data (const T& v): d_ (v),             v_ (true)  {}
       constexpr optional_data (T&& v):      d_ (std::move (v)), v_ (true)  {}
+
+      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_));}
 #else
       optional_data ():           e_ (),              v_ (false) {}
       optional_data (nullopt_t):  e_ (),              v_ (false) {}
       optional_data (const T& v): d_ (v),             v_ (true)  {}
       optional_data (T&& v):      d_ (std::move (v)), v_ (true)  {}
+
+      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_));}
 #endif
 
       optional_data& operator= (nullopt_t);
       optional_data& operator= (const T&);
       optional_data& operator= (T&&);
 
-      optional_data (const optional_data&);
-      optional_data (optional_data&&);
-
       optional_data& operator= (const optional_data&);
       optional_data& operator= (optional_data&&);
     };
@@ -126,17 +132,26 @@ LIBBUTL_MODEXPORT namespace butl
     constexpr optional (nullopt_t)                        {}
     constexpr optional (const T& v): base (v)             {}
     constexpr optional (T&& v):      base (std::move (v)) {}
+
+    constexpr optional (const optional&) = default;
+    constexpr optional (optional&&)      = default;
 #else
     optional ()                                 {}
     optional (nullopt_t)                        {}
     optional (const T& v): base (v)             {}
     optional (T&& v):      base (std::move (v)) {}
+
+    optional (const optional&) = default;
+    optional (optional&&)      = default;
 #endif
 
     optional& operator= (nullopt_t v) {static_cast<base&> (*this) = v;             return *this;}
     optional& operator= (const T& v)  {static_cast<base&> (*this) = v;             return *this;}
     optional& operator= (T&& v)       {static_cast<base&> (*this) = std::move (v); return *this;}
 
+    optional& operator= (const optional&) = default;
+    optional& operator= (optional&&)      = default;
+
     T&       value ()       {return this->d_;}
     const T& value () const {return this->d_;}
 
@@ -148,12 +163,6 @@ LIBBUTL_MODEXPORT namespace butl
 
     bool         has_value () const {return this->v_;}
     explicit operator bool () const {return this->v_;}
-
-    optional (const optional&) = default;
-    optional (optional&&) = default;
-
-    optional& operator= (const optional&) = default;
-    optional& operator= (optional&&) = default;
   };
 
   template <typename T>