1<===> input.scss
2%btnBase {
3  display: none;
4}
5
6@mixin mobile {
7  @media only screen and (min-width:300px) {
8    @content;
9  }
10}
11
12@include mobile {
13  a {
14    @extend %btnBase;
15  }
16}
17<===> error
18Error: You may not @extend an outer selector from within @media.
19       You may only @extend selectors within the same directive.
20input.scss.
21input.scss
22  Use --trace for backtrace.
23
24<===> error-libsass
25Error: You may not @extend selectors across media queries.
26      Use "@extend %btnBase !optional" to avoid this error.
27      on line 7:7 of inpit.scss, in mixin `mobile`
28      from line 11:12 of input.scss
29>>       @extend %btnBase
30
31<===> error-dart-sass
32Error: From line 1, column 1 of input.scss:
33  ,
341 | %btnBase {
35  | ^^^^^^^^^
36  '
37You may not @extend selectors across media queries.
38   ,
3913 |     @extend %btnBase;
40   |     ^^^^^^^^^^^^^^^^
41   '
42  input.scss 13:5  root stylesheet
43