[RF] Implement move constructor/assignment operator of RooLinkedListIter

guitargeek · guitargeek · commit f7adfb5c7816 · 2021-04-19T15:12:15.000+02:00
Setting the move constructor and move assignment operator to = default
causes linker errors because the copy assignment operator is not
implemented in the TIterator base class.

Having the RooLinkedListIter move constructor and assignment operators
work is important to keep user code compatibility.
diff --git a/roofit/roofitcore/inc/RooLinkedListIter.h b/roofit/roofitcore/inc/RooLinkedListIter.h
@@ -210,9 +210,18 @@ class RooLinkedListIter final : public TIterator {
   }
 
   RooLinkedListIter(const RooLinkedListIter &) = delete;
-  RooLinkedListIter(RooLinkedListIter &&) = default;
   RooLinkedListIter & operator=(const RooLinkedListIter &) = delete;
-  RooLinkedListIter & operator=(RooLinkedListIter &&) = default;
+
+  // Setting the move constructor and assignment operator to = default might
+  // seem to work, but it causes linker errors when using it because
+  // TIterator::operator= is not implemented.
+  RooLinkedListIter(RooLinkedListIter && other)
+    : fIterImpl{std::move(other.fIterImpl)}
+  {}
+  RooLinkedListIter & operator=(RooLinkedListIter && other) {
+    fIterImpl = std::move(other.fIterImpl);
+    return *this;
+  }
 
   TIterator &operator=(const TIterator & other) override {fIterImpl->operator=(other); return *this;}
   const TCollection *GetCollection() const override {return nullptr;}
