returnDanglingLifetime and danglingLifetime false positives

[Nikita Leontiev]

cppcheck 2.21.0 generates returnDanglingLifetime and danglingLifetime for the following code:

#include <string>

std::string to_string(const char* str)
{
    return str;
}

std::string get()
{
    std::string local;
    return to_string(local.c_str());
}

void get(std::string & str)
{
    std::string local;
    str = to_string(local.c_str());
}

test\main.cpp:11:18: error: Returning object that points to local variable 'local' that will be invalid when returning. [returnDanglingLifetime]
 return to_string(local.c_str());
                 ^
test\main.cpp:11:30: note: Pointer to container is created here.
 return to_string(local.c_str());
                             ^
test\main.cpp:11:30: note: Passed to 'to_string'.
 return to_string(local.c_str());
                             ^
test\main.cpp:10:14: note: Variable created here.
 std::string local;
             ^
test\main.cpp:11:18: note: Returning object that points to local variable 'local' that will be invalid when returning.
 return to_string(local.c_str());
                 ^
test\main.cpp:17:2: error: Non-local variable 'str' will use object that points to local variable 'local'. [danglingLifetime]
 str = to_string(local.c_str());
 ^
test\main.cpp:17:29: note: Pointer to container is created here.
 str = to_string(local.c_str());
                            ^
test\main.cpp:17:29: note: Passed to 'to_string'.
 str = to_string(local.c_str());
                            ^
test\main.cpp:16:14: note: Variable created here.
 std::string local;
             ^
test\main.cpp:17:2: note: Non-local variable 'str' will use object that points to local variable 'local'.
 str = to_string(local.c_str());
 ^

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/14818