title: Using std::vector does not work
body: <p>Why the following code doesn't compile,</p>
  
  <pre><code>#include &lt;vector&gt;
  using std::vector;
  vector&lt;int&gt; v; // Error: too few template arguments, expected 2
  </code></pre>
  
  <p>but the same code with <code>map</code> (and <code>pair</code>, <code>set</code>, ...) instead of <code>vector</code> works?</p>
  
  <pre><code>#include &lt;map&gt;
  using std::map;
  map&lt;int, int&gt; m; // OK
  </code></pre>
  
  <p>And also this code works fine:</p>
  
  <pre><code>#include &lt;vector&gt;
  using namespace std;
  vector&lt;int&gt; v; // OK
  </code></pre>
  
  <p>I know that constructor of <code>std::vector</code> has two arguments (type and allocator), but why <code>vector</code> behaviour is so different from other containers?</p>
  
  <p>UPD: I'm sorry, this is my mistake. Actually the code does compile, but CLion marks it as an error. So it is CLion's bug.
  <a href="https://i.stack.imgur.com/LvzO8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LvzO8.png" alt="enter image description here"></a></p>