static inside lambda results in incorrect code #467
Description
The code
#include <iostream>
int main()
{
auto l = []()
{
static int n{};
std::cout << ++n;
};
}generates code with two separate functions with the same static variable declared twice
#include <iostream>
int main()
{
class __lambda_5_11
{
public:
inline void operator()() const
{
static int n = {};
std::cout.operator<<(++n);
}
using retType_5_11 = void (*)();
inline /*constexpr */ operator retType_5_11 () const noexcept
{
return __invoke;
};
private:
static inline void __invoke()
{
static int n = {};
std::cout.operator<<(++n);
}
public:
// /*constexpr */ __lambda_5_11() = default;
};
__lambda_5_11 l = __lambda_5_11{};
return 0;
}If one were to run the generated code with some direct calls of the lambda and some calls of it through a function pointer, it would result in incorrect results.
For example, you would get 123412 if you called it 4 times directly and then 2 times through a function pointer when using the generated code from cppinsights (whereas the original lambda would print 123456):
l();
l();
l();
l();
(+l)();
(+l)();