nested mixins ignore guards

[ESchuderer]

Is this a wanted behavior? I've expected to give no output at all.

Code

@var: false;

.mixin (...) when (@var) {
  mixin {
    content: 'mixin';
  }

  .nested (...) {
    nested {
      content: 'nested';
    }
  }
}

.mixin;
.mixin.nested;

Output

nested {
  content: 'nested';
}

[ESchuderer]

Practical Example

@theme: none;  // Exchange with flat, to make it work!

#button (...) {
  display: inline-block;

  cursor: pointer;
  line-height: normal;
  text-align: center;
  user-select: none;
  vertical-align: top;
  white-space: nowrap;
}

#button (@background: backround; @color: color; @border: border) when (@theme = flat) {
  .hover (@background-hover: @background; @color-hover: @color; @border-hover: @color-hover) when (@theme = flat) {
    border-color: @border-hover;

    background-color: @background-hover;
    color: @color-hover;
  }
}

button {
  #button;
  #button.hover;
}

Even when the mixins are disabled, I get this Name error: variable @background is undefined, until I activate one of my themes where the variables are defined.

[lukeapage]

hrmm, yes, its undefined what should happen. I confirm that less only looks at guards on the "top" mixin - when you do #mixin.inner it looks up the mixin and evaluates it without taking into account whether it is in a guarded scope. not sure what should happen though.

[SomMeri]

It ignores also mandatory parameters e.g., following will fail:

@var: false;

.mixin (@something) when (@something>2) {
  .nested (...) {
    nested {
      content: 'nested' @something;
    }
  }
}

.mixin () {
  .nested () {
    nested {
      content: 'alternative';
    }
  }
}

.mixin.nested;

SyntaxError: variable @something is undefined in ...on line 21, column 1

I would guess that inner mixin is written with assumption that guard conditions of outer mixin are satisfied and that mandatory parameters on the way up are filled. E.g. I would expect it to return following:

nested {
  content: 'alternative';
}

[SomMeri]

Closing this since it will be fixed in v2.0