menu.html.twig has an unnecessary import inside its macro

Problem/Motivation

menu.html.twig has a clever recursive macro, but according to the Twig documentation there is an unnecessary import inside of it.

We can see in the compiled Twig template that the import is doing an unnecessary variable reinitialization.

doDisplay method (main code path, doesn't change with this patch):

protected function doDisplay(array $context, array $blocks = array())
{
    // line 16
    $context["menus"] = $this;
    // line 17
    echo "
";
    // line 22
    echo $this->env->getExtension('drupal_core')->renderVar($context["menus"]->getmenu_links((isset($context["items"]) ? $context["items"] : null), (isset($context["attributes"]) ? $context["attributes"] : null), 0));
    echo "

";
}

Before

ob_start();
try {
    // line 25
    echo "  ";
    $context["menus"] = $this;
    // line 26
    echo "  ";
    if ((isset($context["items"]) ? $context["items"] : null)) {
        // line 27

After

ob_start();
try {
    // line 25
    echo "  ";
    if ((isset($context["items"]) ? $context["items"] : null)) {
        // line 26

Because this is the only Twig macro (and only recursive Twig macro) in core it should probably set a better example.

Beta phase evaluation

Proposed resolution

Remove the unnecessary import from inside the macro.

Remaining tasks

Patch (both Classy and core's menu.html.twig)
Patch review

User interface changes

n/a

API changes

n/a