b47dbf5e5e
Product nodes are eagerly resolved during parse time, but sum nodes are not. This might cause floating point inprecision in sum nodes, which leads to invalid calculations, e.g. `round(down, (7 - 1) / 3, 1)` would end up being `round(down, (2.3333333 - 0.33333334), 1)`, then `round(down, 1.99999996, 1)`, which equals `1`, which is incorrect. Differential Revision: https://phabricator.services.mozilla.com/D225936