In v0.1.10, you could use nested vars that would be parsed before being set to a mixin, e.g:
:root {
--original-var: 4px;
--nested-var: calc(2 * var(--original-var));
}
.class-name {
@mixin mixinName var(--nested-var);
}
nested var would be resolved in the mixin as calc(2 * 4px)
As of v2, this no longer works and is instead simply passed through as calc(2 * var(--original-var)) (i.e not resolving the original var)