Extending concatenated selectors

[zerkms]

Assuming that I have a LESS like this

.layout {
  &__sidebar {
    color: red;
  }
}

.layout__sidebar {
  background-color: yellow;
}

.foo {
  &:extend(.layout__sidebar);
}

I expect it to be compiled into

.layout__sidebar,
.foo {
  color: red;
}
.layout__sidebar,
.foo {
  background-color: yellow;
}

but it compiles to

.layout__sidebar {
  color: red;
}
.layout__sidebar,
.foo {
  background-color: yellow;
}

What my expectations are based on:

1. on the documentation about :extend
2. on the fact that something very similar works fine

.layout {
  &.sidebar {
    color: red;
  }
}

.layout.sidebar {
  background-color: yellow;
}

.foo {
  &:extend(.layout.sidebar);
}

Codepen demos:

1. with classname string concatenation http://codepen.io/zerkms/pen/vGJvBV
2. with just combination of class names http://codepen.io/zerkms/pen/oxeJYP

Would you consider this a bug? If not, it must be explicitly noted in the documentation that the selector strings concatenation does not work with :extend

Thanks.

PS: I also asked a question on stackoverflow http://stackoverflow.com/q/36322581/251311

[Justineo]

This might be another duplicate of #2200. I believe this is a frequently requested feature but now there are several major feature requests with nobody ready to implement (for quite a long time). I know the core team have no obligations to do anything, but it's really hard to expect some random users from the community to drive the project forward.

[zerkms]

It is a duplicate indeed, thank you.