less中在calc使用变量报错是哪里需要配置还是写法不对？

Question

变量不在calc里用是正常的

Answer 1

<style lang="less">
.el-upload--picture-card {
-   line-height: calc(var(--thumbnailWidth) - 2px);
+    line-height: ~'calc(var(--thumbnailWidth) - 2px)';
}
</style>

https://github.com/less/less.js/issues/974#issuecomment-9229470