How to properly merge post in LESS for compact post in css?

Question

Less

We have an entry in the LESS file

.breadcrumb {
  &.main,
  &.path {
     & a:hover {
      color: red;
    }
  }
}

.right-sidepanel {
    &-article,
    &-moreover {
      a {
        color: red;
      }
    }
  }

.left-sidepanel {
    .panel {
      &-heading,
      &-body a {
        color: red;
      }
    }
  }

I just can’t think of a solution for the most compact entry in both less and the output in css
. The output is

.breadcrumb.main a:hover,
.breadcrumb.path a:hover {
  color: red;
}
.right-sidepanel-article a,
.right-sidepanel-moreover a {
  color: red;
}
.left-sidepanel .panel-heading,
.left-sidepanel .panel-body a {
  color: red;
}

/*  Как исправить файл Less, чтобы на выходе была компактная запись вида   */

.breadcrumb.main a:hover,
.breadcrumb.path a:hover,
.right-sidepanel-article a,
.right-sidepanel-moreover a,
.left-sidepanel .panel-heading,
.left-sidepanel .panel-body a {
  color: red;
}

Thank you very much for the science

Answer 1

Perhaps this will help you: websketches.ru/less/extend

.breadcrumb {
  &.main,
  &.path {
     & a:hover {
      color: red;
    }
  }
}

.right-sidepanel {
    &-article,
    &-moreover {
      a {
        &:extend(.breadcrumb.main a:hover);
      }
    }
  }

.left-sidepanel {
    .panel {
      &-heading,
      &-body a {
        &:extend(.breadcrumb.main a:hover);
      }
    }
  }

less2css.org/#%7B%22less%22%3A%22.breadcrumb%20%7B...

Answer 2

I can say that in SASS properties are automatically grouped, but not for this example.
So it's better to take care of minifying files.