grid-area prefixing missing when used with grid-template with grid area definitions

I played around with the grid-template shorthand syntax today and discovered, that is seems only to be only partially implemented:

As per i. e. https://developer.mozilla.org/de/docs/Web/CSS/grid-template, use can use the following values for grid-template:

a) grid-template-rows / grid-template-columns values b) grid-template-areas grid-template-rows / grid-template-column values

a) seems to be working correctly.

grid-template: 1fr 1fr / auto

is transformed to

  -ms-grid-rows: 1fr 1fr;
  -ms-grid-columns: auto;

But b) seems not to be implemented. See example below:

SCSS input:

.box {
    display: grid;
    grid-template: "a b" auto / 1fr 1fr;

    #a {
        grid-area: a;
    }

    #b {
        grid-area: b;
    }
}

CSS output: Notice: -ms-grid-row and -ms-grid-column props are missing for #b.

.box {
  display: -ms-grid;
  display: grid;
  grid-template: "a b" auto / 1fr 1fr;
}

.box #a {
  grid-area: a;
}

.box #b {
  grid-area: b;
}

Would be very nice if you guys could also implement this use case.

[yepninja]

Done here #992

[ai]

Released in 8.1