Compiling clamp with mixed units vw and rem fails

[rintisch]

When compiling e.g. clamp(0.2rem, 0.2rem + 0.12vw, 0.3rem) the Compiler fails in the method compileString() line 573 with the message Incompatible units vw and rem.: line: <line-number>, column: <column-number>.

It works when using clamp(0.2rem, calc(0.2rem + 0.12vw), 0.3rem) but calc() is optional ,see https://web.dev/min-max-clamp/

When using a calculation inside of a min(), max(), or clamp() function, you can remove the call to calc(). For example, writing font-size: max(calc(0.5vw - 1em), 2rem) would be the same as font-size: max(0.5vw - 1em, 2rem).

[stof]

We haven't implemented support for first-class calc yet in scssphp (doing that in our 1.x codebase is too hard, so this is scheduled to be part of the upcoming 2.0 release, once I have time again to move it forward). Because of that, 0.2rem + 0.12vw is interpreted as a Sass addition. Wrapping it in calc() works because calc() has a special parsing.

When looking at the compatibility notes in the documentation about calculations, the support in scssphp 1.x is equivalent to the support in libsass.

[rintisch]

@stof Thank you for the fast feedback and explanations!