references to variables "returned" by a called mixin couldn't be resolved

[movalz]

In newer LESS versrions (since 1.4) it's possible to use a mixin as a function call (see http://lesscss.org/features/#mixins-as-functions-feature): the variables defined inside the mixin body are accessible in a calling mixin.

Example:

.mainMixin() {
.subMixin();
height: @subMixinReturnValue;
}

.subMixin() {
@subMixinReturnValue: 17px;
}

LESS editor can't resolve the reference to "@subMixinReturnValue" in mixin .mainMixin.