Don't rely on default assignment operators for cap clients since they break with…

Don't rely on default assignment operators for cap clients since they break with double virtual inheritance.

c++/src/capnp/compiler/capnpc-c++.c++

@@ -1307,20 +1307,19 @@ private:
           "  typedef ", fullName, " Calls;\n"
           "  typedef ", fullName, " Reads;\n"
           "\n"
-          "  inline Client(decltype(nullptr))\n"
-          "      : ::capnp::Capability::Client(nullptr) {}\n"
-          "  inline explicit Client(::kj::Own<const ::capnp::ClientHook>&& hook)\n"
-          "      : ::capnp::Capability::Client(::kj::mv(hook)) {}\n"
+          "  Client(decltype(nullptr));\n"
+          "  explicit Client(::kj::Own<const ::capnp::ClientHook>&& hook);\n"
           "  template <typename T, typename = ::kj::EnableIf< ::kj::canConvert<T*, Server*>()>>\n"
-          "  inline Client(::kj::Own<T>&& server,\n"
-          "                const ::kj::EventLoop& loop = ::kj::EventLoop::current())\n"
-          "      : ::capnp::Capability::Client(::kj::mv(server), loop) {}\n"
+          "  Client(::kj::Own<T>&& server,\n"
+          "         const ::kj::EventLoop& loop = ::kj::EventLoop::current());\n"
           "  template <typename T, typename = ::kj::EnableIf< ::kj::canConvert<T*, Client*>()>>\n"
-          "  inline Client(::kj::Promise<T>&& promise,\n"
-          "                const ::kj::EventLoop& loop = ::kj::EventLoop::current())\n"
-          "      : ::capnp::Capability::Client(::kj::mv(promise), loop) {}\n"
-          "  inline Client(::kj::Exception&& exception)\n"
-          "      : ::capnp::Capability::Client(::kj::mv(exception)) {}\n"
+          "  Client(::kj::Promise<T>&& promise,\n"
+          "         const ::kj::EventLoop& loop = ::kj::EventLoop::current());\n"
+          "  Client(::kj::Exception&& exception);\n"
+          "  Client(const Client&) = default;\n"
+          "  Client(Client&&) = default;\n"
+          "  Client& operator=(const Client& other);\n"
+          "  Client& operator=(Client&& other);\n"
           "\n",
           KJ_MAP(m, methods) { return kj::mv(m.clientDecls); },
           "\n"
@@ -1349,7 +1348,31 @@ private:
           "};\n"
           "\n"),
 
-      kj::strTree(),
+      kj::strTree(
+          "inline ", fullName, "::Client::Client(decltype(nullptr))\n"
+          "    : ::capnp::Capability::Client(nullptr) {}\n"
+          "inline ", fullName, "::Client::Client(\n"
+          "    ::kj::Own<const ::capnp::ClientHook>&& hook)\n"
+          "    : ::capnp::Capability::Client(::kj::mv(hook)) {}\n"
+          "template <typename T, typename>\n"
+          "inline ", fullName, "::Client::Client(\n"
+          "    ::kj::Own<T>&& server, const ::kj::EventLoop& loop)\n"
+          "    : ::capnp::Capability::Client(::kj::mv(server), loop) {}\n"
+          "template <typename T, typename>\n"
+          "inline ", fullName, "::Client::Client(\n"
+          "    ::kj::Promise<T>&& promise, const ::kj::EventLoop& loop)\n"
+          "    : ::capnp::Capability::Client(::kj::mv(promise), loop) {}\n"
+          "inline ", fullName, "::Client::Client(::kj::Exception&& exception)\n"
+          "    : ::capnp::Capability::Client(::kj::mv(exception)) {}\n"
+          "inline ", fullName, "::Client& ", fullName, "::Client::operator=(const Client& other) {\n"
+          "  ::capnp::Capability::Client::operator=(other);\n"
+          "  return *this;\n"
+          "}\n"
+          "inline ", fullName, "::Client& ", fullName, "::Client::operator=(Client&& other) {\n"
+          "  ::capnp::Capability::Client::operator=(kj::mv(other));\n"
+          "  return *this;\n"
+          "}\n"
+          "\n"),
 
       kj::strTree(
           KJ_MAP(m, methods) { return kj::mv(m.sourceDefs); },

c++/src/capnp/rpc.c++

@@ -2491,6 +2491,8 @@ private:
           return nullptr;
         }
     }
+
+    KJ_UNREACHABLE;
   }
 
   void handleReturn(kj::Own<IncomingRpcMessage>&& message, const rpc::Return::Reader& ret) {