Currently `calc()` is supported as a CSS mathematical function. The CSS Values and Units Level 4 Specification describes a list of math functions [1] consisting of `calc()` in addition to `min()` and `max()`. Suggest implementing recent specification changes. The motivation for opening this bug is the reference to the aforementioned mathematical functions in the HTML Standard [2], which supports the appearance of mathematical functions in the `sizes` attribute on <img> elements. [1]: https://drafts.csswg.org/css-values/#math-function [2]: https://github.com/whatwg/html/pull/3084 & https://github.com/w3c/web-platform-tests/pull/10167
Note this issue might be a duplicate of one, though I'm not sure. Tab told me that the reason `min()` and `max()` made it into the spec as mathematical functions was because Apple said they were going to implement them, so there might already be an issue tracking their implementation. Either way... :)
https://wpt.fyi/results/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute-width-1000px.html?label=experimental&label=master&aligned shows 4 Safari-only test failures due to min() and max() not being supported.