invalidContainerReference false positive

[Cyphall]

Using emplace_back on a vector may indeed invalidate references to existing objects, but not to the emplaced object itself.

Sample code:

#include <vector>
#include <memory>

struct Value
{
    int data;
};

int main()
{
    std::vector<std::unique_ptr<Value>> values;

    for (int i = 0; i < 5; i++)
    {
        std::unique_ptr<Value>& value = values.emplace_back(std::make_unique<Value>(i));
        value->data = 5;
    }

    return 0;
}

cppcheck error (file paths were removed):

error: Reference to values that may be invalid. [invalidContainerReference]
  value->data = 5;
  ^
note: Assigned to reference.
  std::unique_ptr<Value>& value = values.emplace_back(std::make_unique<Value>(i));
                                ^
note: Accessing container.
  std::unique_ptr<Value>& value = values.emplace_back(std::make_unique<Value>(i));
                                         ^
note: Assuming condition is true.
 for (int i = 0; i < 5; i++)
                   ^
note: After calling 'emplace_back', iterators or references to the container's data may be invalid .
  std::unique_ptr<Value>& value = values.emplace_back(std::make_unique<Value>(i));
                                         ^
note: Reference to values that may be invalid.
  value->data = 5;
  ^

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/14013