Latest commit 1143ac0 Dec 29, 2016 @connec connec Allow `@` values as indices in `for` expressions
This loosens the compilation of `for` expressions to allow the index
variable to be an `@` value, e.g.

    do @visit for @node, @index in nodes

Within `@visit`, the index of the current node (`@node`) would be
available as `@index`.

Fixes #4411.