<===> input.scss
$map: (
  alpha: 1,
  beta: 2,
  gamma: 3,
  delta: (
    eta: 5,
    eta: 6,
  ),
);

<===> error
Error: Duplicate key "eta" in map (eta: 5, eta: 6).
        on line 5 of input.scss
  Use --trace for backtrace.

<===> error-dart-sass
Error: Duplicate key.
  ,
6 |     eta: 5,
  |     === first key
7 |     eta: 6,
  |     ^^^ second key
  '
  input.scss 7:5  root stylesheet