commit 63bec405990a204a987a87d25d174e03c1164eb5
author David Tolnay <dtolnay@gmail.com> Thu Feb 11 23:18:04 2021 -0800
committer David Tolnay <dtolnay@gmail.com> Thu Feb 11 23:19:16 2021 -0800
tree a0562882fa598de9e783dd708cf409bc92f07238
parent 19b488c286d99c986b34bfc152e19b68b67c1a02

Disallow assignment to rvalue

include/cxx.h

diff --git a/include/cxx.h b/include/cxx.h
index 0744f8c..654b176 100644
--- a/include/cxx.h
+++ b/include/cxx.h
@@ -44,8 +44,8 @@
   String(const char *);
   String(const char *, std::size_t);
 
-  String &operator=(const String &) noexcept;
-  String &operator=(String &&) noexcept;
+  String &operator=(const String &) & noexcept;
+  String &operator=(String &&) & noexcept;
 
   explicit operator std::string() const;
 
@@ -97,7 +97,7 @@
   Str(const char *);
   Str(const char *, std::size_t);
 
-  Str &operator=(const Str &) noexcept = default;
+  Str &operator=(const Str &) & noexcept = default;
 
   explicit operator std::string() const;
 
@@ -144,8 +144,8 @@
 struct copy_assignable_if<false> {
   copy_assignable_if() noexcept = default;
   copy_assignable_if(const copy_assignable_if &) noexcept = default;
-  copy_assignable_if &operator=(const copy_assignable_if &) noexcept = delete;
-  copy_assignable_if &operator=(copy_assignable_if &&) noexcept = default;
+  copy_assignable_if &operator=(const copy_assignable_if &) & noexcept = delete;
+  copy_assignable_if &operator=(copy_assignable_if &&) & noexcept = default;
 };
 } // namespace detail
 
@@ -159,8 +159,8 @@
   Slice() noexcept;
   Slice(T *, std::size_t count) noexcept;
 
-  Slice &operator=(const Slice<T> &) noexcept = default;
-  Slice &operator=(Slice<T> &&) noexcept = default;
+  Slice &operator=(const Slice<T> &) & noexcept = default;
+  Slice &operator=(Slice<T> &&) & noexcept = default;
 
   T *data() const noexcept;
   std::size_t size() const noexcept;
@@ -248,7 +248,7 @@
   explicit Box(const T &);
   explicit Box(T &&);
 
-  Box &operator=(Box &&) noexcept;
+  Box &operator=(Box &&) & noexcept;
 
   const T *operator->() const noexcept;
   const T &operator*() const noexcept;
@@ -293,8 +293,8 @@
   Vec(Vec &&) noexcept;
   ~Vec() noexcept;
 
-  Vec &operator=(Vec &&) noexcept;
-  Vec &operator=(const Vec &);
+  Vec &operator=(Vec &&) & noexcept;
+  Vec &operator=(const Vec &) &;
 
   std::size_t size() const noexcept;
   bool empty() const noexcept;
@@ -371,8 +371,8 @@
   Error(Error &&) noexcept;
   ~Error() noexcept override;
 
-  Error &operator=(const Error &);
-  Error &operator=(Error &&) noexcept;
+  Error &operator=(const Error &) &;
+  Error &operator=(Error &&) & noexcept;
 
   const char *what() const noexcept override;
 
@@ -735,7 +735,7 @@
 }
 
 template <typename T>
-Box<T> &Box<T>::operator=(Box &&other) noexcept {
+Box<T> &Box<T>::operator=(Box &&other) & noexcept {
   if (this->ptr) {
     this->drop();
   }
@@ -823,7 +823,7 @@
 }
 
 template <typename T>
-Vec<T> &Vec<T>::operator=(Vec &&other) noexcept {
+Vec<T> &Vec<T>::operator=(Vec &&other) & noexcept {
   this->drop();
   this->repr = other.repr;
   new (&other) Vec();
@@ -831,7 +831,7 @@
 }
 
 template <typename T>
-Vec<T> &Vec<T>::operator=(const Vec &other) {
+Vec<T> &Vec<T>::operator=(const Vec &other) & {
   if (this != &other) {
     this->drop();
     new (this) Vec(other);