@mixin a-mixin($required, $arg1: default-val1, $arg2: default-val2) {
required: $required;
arg1: $arg1;
arg2: $arg2;
}
.mixed { @include a-mixin(foo, $arg2: non-default-val2); }
@mixin a-mixin($required, $arg1: default-val1, $arg2: default-val2) {
required: $required;
arg1: $arg1;
arg2: $arg2;
}
.mixed { @include a-mixin(foo, $arg2: non-default-val2); }