Child selectors in function rules

[afrankel-sfdo]

All variants of child selectors in a function rule don't appear to work. Non-function rules work as expected.

direct: props => ({
    color: theme.error,
    "& span": {
      color: theme.color
    }
  }),

https://codesandbox.io/s/llv18nznnm

[kof]

I think it is the same as #706

[afrankel-sfdo]

@kof seems reasonable, wasn't sure if media queries and child selectors are handled differently.

[kof]

tbc in #682