Math expressions directly assigned to a CSS custom property are not computed.

[anrikun]

  --test1: (1 / 2);

  @value: (1 / 2);
  --test2: @value;

compiles to:

  --test1: (1 / 2);
  --test2: 0.5;

I would expect both to compile to 0.5
I can't find any mention of this in documentation.

EDIT: see less/less.js#3800