omitting the return type in C++11 lambda

As far as I know, in standard C++11 (not C++14), when omitting the return type of a lambda, its return type is deduced to be:

1. The type of the returned expression, whenever the lambda consists of only one return statement, or


2. void in all other cases.

Consider now this code:

#include <iostream>

auto closure = [](int x)
{
    x++;
    return x;
};

int main()
{
    int y = closure(10);
    std::cout << y << std::endl;
}

This should fall under case 2., however the code compiles as if were C++14 with auto type deduction, in both g++4.9.2, g++5 and clang++, with -pedantic -Wall -Wextra -std=c++11. What's going on here? Am I interpreting the standard wrong?