Parametric Mixins

[mattstyles]

I'm not sure, but I reckon these should maybe be allowed. What I'm worried about is their abuse, leading to additionally stamped out content. Actually, maybe conformance could check for multiple uses of the exact same parametric mixin and allow different mixins i.e. the same css output is warned against but using mixins to stamp out unique bits of css is ok

e.g

.m-makeButton( @color: rgb( 240, 240, 240), @color-bg: rgb( 60, 60, 60 ) ) {
  color: @color;
  background: @color-bg;

  &:hover {
    cursor: pointer;
    background: desaturate( @color-bg, 10% );
  }
}

.Button {
  .m-makeButton( @color: rgb( 0, 0, 0 ), @color-bg: rgb( 240, 240, 240 );
}
.Button--primary {
  .m-makeButton( @color: @--color-white, @color: @--color-primary);
}