Dart-sass

* Elements without a namespace (such as `div`) are no longer unified with
elements with the empty namespace (such as `|div`). This unification didn't
match the results returned by `is-superselector()`, and was not guaranteed to
be valid.

* Support `&` within `at-root`.

* Properly error when a compound selector is followed immediately by `&`.

* Properly handle variable scoping in `at-root` and nested properties.

* Properly handle placeholder selectors in selector pseudos.

* Properly short-circuit the `or` and `and` operators.

* Support `--$variable`.

* Don't consider unitless numbers equal to numbers with units.

* Warn about using named colors in interpolation.

* Don't emit loud comments in functions.

* Detect import loops.

* Fix `import` with a `supports()` clause.

* Forbid functions named "and", "or", and "not".

* Fix `type-of()` with a function.

* Emit a nicer error for invalid tokens in a selector.

* Fix `invert()` with a `$weight` parameter.

* Fix a unit-parsing edge-cases.

* Always parse imports with queries as plain CSS imports.

* Support `&` followed by a non-identifier.

* Properly handle split media queries.

* Properly handle a placeholder selector that isn't at the beginning of a
compound selector.

* Fix more `str-slice()` bugs.

* Fix the `%` operator.

* Allow whitespace between `=` and the mixin name in the indented syntax.

* Fix some slash division edge cases.

* Fix `not` when used like a function.

* Fix attribute selectors with single-character values.

* Fix some bugs with the `call()` function.

* Properly handle a backslash followed by a CRLF sequence in a quoted string.

* Fix numbers divided by colors.

* Support slash-separated numbers in arguments to plain CSS functions.

* Error out if a function is passed an unknown named parameter.

* Improve the speed of loading large files on Node.

* Don't consider browser-prefixed selector pseudos to be superselectors of
differently- or non-prefixed selector pseudos with the same base name.

* Fix an `extend` edge case involving multiple combinators in a row.

* Fix a bug where a `content` block could get incorrectly passed to a mixin.

* Properly isolate the lexical environments of different calls to the same mixin
and function.

* Add the `content-exists()` function.

* Support interpolation in loud comments.

* Fix a bug where even valid semicolons and exclamation marks in custom property
values were disallowed.

* Disallow invalid function names.

* Disallow extending across media queries.

* Properly parse whitespace after `...` in argument declaration lists.

* Support terse mixin syntax in the indented syntax.

* Fix `at-root` query parsing.

* Support special functions in `-moz-document`.

* Support `...` after a digit.

* Fix some bugs when treating a map as a list of pairs.

* Fix `function-exists()`, `variable-exists()`, and `mixin-exists()` to use the
lexical scope rather than always using the global scope.

* `str-index()` now correctly inserts at negative indices.

* Properly parse `url()`s that contain comment-like text.

* Fix a few more small `extend` bugs.

* Fix a bug where interpolation in a quoted string was being dropped in some
circumstances.

* Properly handle `for` rules where each bound has a different unit.

* Forbid mixins and functions from being defined in control directives.

* Fix a superselector-computation edge case involving `:not()`.

* Gracefully handle input files that are invalid UTF-8.

* Print a Sass stack trace when a file fails to load.

* Allow `var()` to be passed to `rgb()`, `rgba()`, `hsl()`, and `hsla()`.

* Fix conversions between numbers with `dpi`, `dpcm`, and `dppx` units.
Previously these conversions were inverted.

* Don't crash when calling `str-slice()` with an `$end-at` index lower than the
`$start-at` index.

* `str-slice()` now correctly returns `""` when `$end-at` is negative and points
before the beginning of the string.

* Interpolation in quoted strings now properly preserves newlines.

* Don't crash when passing only `$hue` or no keyword arguments to
`adjust-color()`, `scale-color()`, or `change-color()`.

* Preserve escapes in identifiers. This used to only work for identifiers in
SassScript.

* Fix a few small `extend` bugs.

* Fix bounds-checking for `opacify()`, `fade-in()`, `transparentize()`, and
`fade-out()`.

* Fix a bug with `extend` superselector calculations.

* Fix some cases where `{...}--` would fail to parse in selectors.

* Allow a single number to be passed to `saturate()` for use in filter contexts.

* Fix a bug where `**/` would fail to close a loud comment.

* Fix a bug where mixin and function calls could set variables incorrectly.

* Move plain CSS `import`s to the top of the document.

* Add support for bracketed lists.

* Add support for Unicode ranges.

* Add support for the Microsoft-style `=` operator.

* Print the filename for `debug` rules.

* Fix a bug where `1 + - 2` and similar constructs would crash the parser.

* Fix a bug where `extend` produced the wrong result when used with
selector combinators.

* Fix a bug where placeholder selectors were not allowed to be unified.

* Fix the `mixin-exists()` function.

* Fix `:nth-child()` and `:nth-last-child()` parsing when they contain `of
selector`.