================
@@ -260,9 +260,22 @@ void PointerToVectorElement() {
}
void SelfInvalidatingMap() {
- std::unordered_map<int, int> mp;
- mp[1] = 1;
- mp[2] = mp[1]; // FIXME: Detect this. We are mising a UseFact for the
assignment params.
+ std::unordered_map<int, std::string> mp;
+ // TODO: We do not have a way to differentiate between pointer stability and
iterator stability!
+ // std::unordered_map and other containers provide pointer/reference
stability. Therefore the
+ // following is safe in practice.
+ // On the other hand, std::flat_hash_map (since C++23) does not provide
pointer stability on
+ // insertion and following is unsafe for this container.
+ mp[1] = "42";
+ mp[2] = mp[1]; // expected-warning {{object whose reference is captured is
later invalidated}} \
----------------
usx95 wrote:
This gets interesting. As far as I can think, there is no safe way to write
`mp[2] = mp[1]` without introducing a copy
```cpp
std::string val = mp[1];
mp[2] = val;
// or
mp[2] = std::string(mp[1]);
```
:disappointed_relieved:
https://github.com/llvm/llvm-project/pull/180446
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