False positive: [invalidContainer]: vector of pointers, back, pop_back

[Andreas Grob]

#include <vector>
#include <iostream>

struct A {
    ~A() { std::cout << "deleted\n"; }
};

int main() {
    std::vector<A *> v;
    A *a = new A();
    v.push_back(a);
    A *b = v.back();
    v.pop_back();
    std::cout << "pop_back\n";
    delete b;
}

output:

$ ./a.out
pop_back
deleted

cppcheck: commit 5cb3aac
built with: make MATCHCOMPILER=yes FILESDIR=/usr/share/cppcheck HAVE_RULES=yes

$ cppcheck main.cpp
Checking main.cpp ...
main.cpp:15:12: error: Using pointer to local variable 'v' that may be invalid. [invalidContainer]
    delete b;
           ^
main.cpp:12:12: note: Pointer to container is created here.
    A *b = v.back();
           ^
main.cpp:13:5: note: After calling 'pop_back', iterators or references to the container's data may be invalid .
    v.pop_back();
    ^
main.cpp:9:22: note: Variable created here.
    std::vector<A *> v;
                     ^
main.cpp:15:12: note: Using pointer to local variable 'v' that may be invalid.
    delete b;
           ^

[Daniel Marjamäki]

Thanks! I created this ticket: https://trac.cppcheck.net/ticket/9796