diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc87d15..88d72af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,21 +1,40 @@
-## 1.8.2
+## 2.0.0
+
+* **Breaking change**: The `media-logic` migrator has been removed as the
+  [corresponding breaking change][media logic] has been completed in Dart Sass.
+  If you still need to migrate legacy code, use migrator version 1.8.1.
+
+  [media logic]: https://sass-lang.com/documentation/breaking-changes/media-logic/
+
+* Update to be compatible with the latest version of the Dart Sass AST.
 
 ### Calc Functions Interpolation Migrator
 
-* Add parentheses in place of interpolation when necessary to preserve the evaluation order.
+* Add parentheses in place of interpolation when necessary to preserve the
+  evaluation order.
+
+### Division Migrator
+
+* `/` division should now be left untouched in all CSS calculation functions.
+  This was already the case for `calc`, `clamp`, `min`, and `max`, but it now
+  applies to the new functions that Dart Sass 1.67.0 added support for.
 
 ## 1.8.1
 
 ### Calc Functions Interpolation Migrator
 
-* Migration for more than one interpolation or expressions in a calc function parameter.
+* Migration for more than one interpolation or expressions in a calc function
+  parameter.
 
 ## 1.8.0
 
 ### Calc Functions Interpolation Migrator
 
-* Removes interpolation in calculation functions `calc()`, `clamp()`, `min()`, and `max()`. 
-  See the [scss/function-calculation-no-interpolation](https://github.com/stylelint-scss/stylelint-scss/tree/master/src/rules/function-calculation-no-interpolation) rule for more information.
+* Removes interpolation in calculation functions `calc()`, `clamp()`, `min()`,
+  and `max()`. See the [scss/function-calculation-no-interpolation] rule for
+  more information.
+
+  [scss/function-calculation-no-interpolation]: https://github.com/stylelint-scss/stylelint-scss/tree/master/src/rules/function-calculation-no-interpolation
 
 ## 1.7.3
 
diff --git a/lib/src/migration_visitor.dart b/lib/src/migration_visitor.dart
index c90f6e2..d13de19 100644
--- a/lib/src/migration_visitor.dart
+++ b/lib/src/migration_visitor.dart
@@ -13,6 +13,8 @@ import 'package:source_span/source_span.dart';
 
 import 'exception.dart';
 import 'patch.dart';
+import 'util/scope.dart';
+import 'util/scoped_ast_visitor.dart';
 
 /// A visitor that migrates a stylesheet.
 ///
@@ -24,8 +26,7 @@ import 'patch.dart';
 /// If [migrateDependencies] is enabled, this visitor will construct and run a
 /// new instance of itself (using [newInstance]) each time it encounters an
 /// `@import` or `@use` rule.
-abstract class MigrationVisitor
-    with RecursiveStatementVisitor, RecursiveAstVisitor {
+abstract class MigrationVisitor extends ScopedAstVisitor {
   /// A mapping from URLs to migrated contents for stylesheets already migrated.
   final _migrated = <Uri, String>{};
 
@@ -117,26 +118,31 @@ abstract class MigrationVisitor
 
   /// Visits the stylesheet at [dependency], resolved based on the current
   /// stylesheet's URL and importer.
+  ///
+  /// When [forImport] is true, this preserves the [currentScope]. Otherwise,
+  /// the dependency is visited with a new global scope for the new module.
   @protected
   void visitDependency(Uri dependency, FileSpan context,
       {bool forImport = false}) {
     if (dependency.scheme == 'sass') return;
     var result = importCache.import(dependency,
         baseImporter: _importer, baseUrl: _currentUrl, forImport: forImport);
-    if (result != null) {
+    if (result case (var newImporter, var stylesheet)) {
       // If [dependency] comes from a non-relative import, don't migrate it,
       // because it's likely to be outside the user's repository and may even be
       // authored by a different person.
       //
       // TODO(nweiz): Add a flag to override this behavior for load paths
       // (#104).
-      if (result.item1 != _importer) return;
+      if (newImporter != _importer) return;
 
       var oldImporter = _importer;
-      _importer = result.item1;
-      var stylesheet = result.item2;
+      var oldScope = currentScope;
+      _importer = newImporter;
+      if (!forImport) currentScope = Scope();
       visitStylesheet(stylesheet);
       _importer = oldImporter;
+      currentScope = oldScope;
     } else {
       _missingDependencies.putIfAbsent(
           context.sourceUrl!.resolveUri(dependency), () => context);
diff --git a/lib/src/migrator.dart b/lib/src/migrator.dart
index 83092d2..d46addc 100644
--- a/lib/src/migrator.dart
+++ b/lib/src/migrator.dart
@@ -93,7 +93,7 @@ abstract class Migrator extends Command<Map<Uri, String>> {
         throw MigrationException("Could not find Sass file at '$entrypoint'.");
       }
 
-      var migrated = migrateFile(importCache, tuple.item2, tuple.item1);
+      var migrated = migrateFile(importCache, tuple.$2, tuple.$1);
       migrated.forEach((file, contents) {
         if (allMigrated.containsKey(file) && contents != allMigrated[file]) {
           throw MigrationException(
diff --git a/lib/src/migrators/calc_interpolation.dart b/lib/src/migrators/calc_interpolation.dart
index db8d991..b570343 100644
--- a/lib/src/migrators/calc_interpolation.dart
+++ b/lib/src/migrators/calc_interpolation.dart
@@ -33,12 +33,12 @@ class _CalculationInterpolationVisitor extends MigrationVisitor {
       : super(importCache, migrateDependencies);
 
   @override
-  void visitCalculationExpression(CalculationExpression node) {
+  void visitFunctionExpression(FunctionExpression node) {
     const calcFunctions = ['calc', 'clamp', 'min', 'max'];
     final interpolation = RegExp(r'\#{\s*[^}]+\s*}');
     final hasOperation = RegExp(r'[-+*/]+');
     if (calcFunctions.contains(node.name)) {
-      for (var arg in node.arguments) {
+      for (var arg in node.arguments.positional) {
         var newArg = arg.toString();
         for (var match in interpolation.allMatches(arg.toString())) {
           var noInterpolation =
@@ -58,6 +58,6 @@ class _CalculationInterpolationVisitor extends MigrationVisitor {
         }
       }
     }
-    super.visitCalculationExpression(node);
+    super.visitFunctionExpression(node);
   }
 }
diff --git a/lib/src/migrators/division.dart b/lib/src/migrators/division.dart
index abedbca..39827e8 100644
--- a/lib/src/migrators/division.dart
+++ b/lib/src/migrators/division.dart
@@ -10,8 +10,35 @@ import 'package:sass_api/sass_api.dart';
 import '../migration_visitor.dart';
 import '../migrator.dart';
 import '../patch.dart';
+import '../util/scope.dart';
 import '../utils.dart';
 
+/// The CSS calculation functions where slash-division is allowed (unless
+/// there's a user-defined function with the same name).
+const _calcFunctions = {
+  'calc',
+  'clamp',
+  'min',
+  'max',
+  'round',
+  'mod',
+  'rem',
+  'sin',
+  'cos',
+  'tan',
+  'asin',
+  'acos',
+  'atan',
+  'atan2',
+  'pow',
+  'sqrt',
+  'hypot',
+  'log',
+  'exp',
+  'abs',
+  'sign',
+};
+
 /// Migrates stylesheets that use the `/` operator for division to use the
 /// `divide` function instead.
 class DivisionMigrator extends Migrator {
@@ -81,13 +108,16 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
   void visitStylesheet(Stylesheet node) {
     var oldNamespaces = __existingNamespaces;
     var oldUseRules = __useRulesToInsert;
+    var oldScope = currentScope;
     __existingNamespaces = {
       for (var rule in node.uses) rule.url: rule.namespace
     };
     __useRulesToInsert = [];
+    currentScope = Scope();
     super.visitStylesheet(node);
     __existingNamespaces = oldNamespaces;
     __useRulesToInsert = oldUseRules;
+    currentScope = oldScope;
   }
 
   /// Inserts [_useRulesToInsert] before the first existing dependency (or at
@@ -136,9 +166,10 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
 
   /// Allows division within this argument invocation.
   @override
-  void visitArgumentInvocation(ArgumentInvocation invocation) {
+  void visitArgumentInvocation(ArgumentInvocation invocation,
+      {bool inCalcContext = false}) {
     _withContext(() => super.visitArgumentInvocation(invocation),
-        isDivisionAllowed: true, inCalcContext: false);
+        isDivisionAllowed: true, inCalcContext: inCalcContext);
   }
 
   /// If this is a division operation, migrates it.
@@ -157,20 +188,15 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
     }
   }
 
-  /// Visits calculations with [_inCalcContext] set to true.
-  @override
-  void visitCalculationExpression(CalculationExpression node) {
-    _withContext(() {
-      super.visitCalculationExpression(node);
-    }, inCalcContext: true);
-  }
-
   /// Allows division within a function call's arguments, with special handling
-  /// for new-syntax color functions.
+  /// for calc functions and new-syntax color functions.
   @override
   void visitFunctionExpression(FunctionExpression node) {
     if (_tryColorFunction(node)) return;
-    visitArgumentInvocation(node.arguments);
+    var validCalcs = _calcFunctions.difference(currentScope.allFunctionNames);
+    visitArgumentInvocation(node.arguments,
+        inCalcContext:
+            node.namespace == null && validCalcs.contains(node.name));
   }
 
   /// Visits interpolation with [_isDivisionAllowed] and [_inCalcContext] set
@@ -198,9 +224,9 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
   void visitParenthesizedExpression(ParenthesizedExpression node,
       {bool negated = false}) {
     _withContext(() {
-      var expression = node.expression;
-      if (expression is BinaryOperationExpression &&
-          expression.operator == BinaryOperator.dividedBy) {
+      if (node.expression
+          case BinaryOperationExpression(operator: BinaryOperator.dividedBy) &&
+              var expression) {
         if (_visitSlashOperation(expression) && !negated) {
           addPatch(patchDelete(node.span, end: 1));
           addPatch(patchDelete(node.span, start: node.span.length - 1));
@@ -215,9 +241,11 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
   /// parenthesized expression.
   @override
   void visitUnaryOperationExpression(UnaryOperationExpression node) {
-    var operand = node.operand;
-    if (node.operator == UnaryOperator.minus &&
-        operand is ParenthesizedExpression) {
+    if (node
+        case UnaryOperationExpression(
+          operator: UnaryOperator.minus,
+          :ParenthesizedExpression operand
+        )) {
       visitParenthesizedExpression(operand, negated: true);
       return;
     }
@@ -244,40 +272,48 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
       return false;
     }
 
-    ListExpression? channels;
-    if (node.arguments.positional.length == 1 &&
-        node.arguments.named.isEmpty &&
-        node.arguments.positional.first is ListExpression) {
-      channels = node.arguments.positional.first as ListExpression?;
-    } else if (node.arguments.positional.isEmpty &&
-        node.arguments.named.containsKey(r'$channels') &&
-        node.arguments.named.length == 1 &&
-        node.arguments.named[r'$channels'] is ListExpression) {
-      channels = node.arguments.named[r'$channels'] as ListExpression?;
-    }
-    if (channels == null ||
-        channels.hasBrackets ||
-        channels.separator != ListSeparator.space ||
-        channels.contents.length != 3 ||
-        channels.contents.last is! BinaryOperationExpression) {
-      return false;
-    }
+    var channels = switch (node.arguments) {
+      ArgumentInvocation(
+        positional: [ListExpression arg],
+        named: Map(isEmpty: true)
+      ) =>
+        arg,
+      ArgumentInvocation(
+        positional: [],
+        named: {r'$channels': ListExpression arg}
+      ) =>
+        arg,
+      _ => null,
+    };
 
-    var last = channels.contents.last as BinaryOperationExpression;
-    if (last.left is! NumberExpression || last.right is! NumberExpression) {
-      // Handles cases like `rgb(10 20 30/2 / 0.5)`, since converting `30/2` to
-      // `divide(30, 20)` would cause `/ 0.5` to be interpreted as division.
-      _patchSpacesToCommas(channels);
-      _patchOperatorToComma(last);
+    if (channels
+        case ListExpression(
+          hasBrackets: false,
+          separator: ListSeparator.space,
+          contents: [_, _, BinaryOperationExpression last]
+        )) {
+      // Handles cases like `rgb(10 20 30/2 / 0.5)`, since converting `30/2`
+      // to `div(30, 20)` would cause `/ 0.5` to be interpreted as division.
+      if (last
+          case BinaryOperationExpression(
+            left: NumberExpression(),
+            right: NumberExpression()
+          )) {
+        // Nothing to patch
+      } else {
+        _patchSpacesToCommas(channels);
+        _patchOperatorToComma(last);
+      }
+      _withContext(() {
+        // Non-null assertion is required because of dart-lang/language#1536.
+        channels.contents[0].accept(this);
+        channels.contents[1].accept(this);
+        last.left.accept(this);
+      }, isDivisionAllowed: true);
+      last.right.accept(this);
+      return true;
     }
-    _withContext(() {
-      // Non-null assertion is required because of dart-lang/language#1536.
-      channels!.contents[0].accept(this);
-      channels.contents[1].accept(this);
-      last.left.accept(this);
-    }, isDivisionAllowed: true);
-    last.right.accept(this);
-    return true;
+    return false;
   }
 
   /// Visits a `/` operation [node] and migrates it to either the `division`
@@ -291,9 +327,10 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
       node.right.accept(this);
       return false;
     }
+    var status = _NumberStatus.of(node);
 
     if ((!_isDivisionAllowed && _onlySlash(node)) ||
-        _isDefinitelyNotNumber(node)) {
+        status == _NumberStatus.no) {
       // Definitely not division
       if (_isDivisionAllowed || _containsInterpolation(node)) {
         // We only want to convert a non-division slash operation to a
@@ -305,7 +342,9 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
       }
       return true;
     }
-    if (_expectsNumericResult || _isDefinitelyNumber(node) || !isPessimistic) {
+    if (_expectsNumericResult ||
+        status == _NumberStatus.yes ||
+        !isPessimistic) {
       // Definitely division
       _withContext(() => super.visitBinaryOperationExpression(node),
           expectsNumericResult: true);
@@ -330,111 +369,74 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
   /// Returns true if patched and false otherwise.
   bool _tryMultiplication(BinaryOperationExpression node) {
     if (!useMultiplication) return false;
-    var divisor = node.right;
-    if (divisor is! NumberExpression) return false;
-    if (divisor.unit != null) return false;
-    if (!_allowedDivisors.contains(divisor.value)) return false;
-    var operatorSpan = node.left.span
-        .extendThroughWhitespace()
-        .end
-        .pointSpan()
-        .extendIfMatches('/');
-    addPatch(Patch(operatorSpan, '*'));
-    addPatch(Patch(node.right.span, '${1 / divisor.value}'));
-    return true;
+    if (node.right case NumberExpression(unit: null, value: var divisor)
+        when _allowedDivisors.contains(divisor)) {
+      var operatorSpan = node.left.span
+          .extendThroughWhitespace()
+          .end
+          .pointSpan()
+          .extendIfMatches('/');
+      addPatch(Patch(operatorSpan, '*'));
+      addPatch(Patch(node.right.span, '${1 / divisor}'));
+      return true;
+    }
+    return false;
   }
 
   /// Visits the arguments of a `/` operation that is being converted into a
   /// call to `slash-list`, converting slashes to commas and removing
   /// unnecessary interpolation.
   void _visitSlashListArguments(Expression node) {
-    if (node is BinaryOperationExpression &&
-        node.operator == BinaryOperator.dividedBy) {
-      _visitSlashListArguments(node.left);
-      _patchOperatorToComma(node);
-      _visitSlashListArguments(node.right);
-    } else if (node is StringExpression &&
-        node.text.contents.length == 1 &&
-        node.text.contents.first is Expression) {
-      // Remove `#{` and `}`
-      addPatch(patchDelete(node.span, end: 2));
-      addPatch(patchDelete(node.span, start: node.span.length - 1));
-      (node.text.contents.first as Expression).accept(this);
-    } else {
-      node.accept(this);
+    switch (node) {
+      case BinaryOperationExpression(operator: BinaryOperator.dividedBy):
+        _visitSlashListArguments(node.left);
+        _patchOperatorToComma(node);
+        _visitSlashListArguments(node.right);
+      case StringExpression(text: Interpolation(contents: [Expression item])):
+        // Remove `#{` and `}`
+        addPatch(patchDelete(node.span, end: 2));
+        addPatch(patchDelete(node.span, start: node.span.length - 1));
+        item.accept(this);
+      default:
+        node.accept(this);
     }
   }
 
-  /// Returns true if we assume that [operator] always returns a number.
-  ///
-  /// This is true for `*` and `%`.
-  bool _returnsNumbers(BinaryOperator operator) =>
-      operator == BinaryOperator.times || operator == BinaryOperator.modulo;
-
   /// Returns true if we assume that [operator] always operators on numbers.
   ///
   /// This is true for `*`, `%`, `<`, `<=`, `>`, and `>=`.
-  bool _operatesOnNumbers(BinaryOperator operator) =>
-      _returnsNumbers(operator) ||
-      operator == BinaryOperator.lessThan ||
-      operator == BinaryOperator.lessThanOrEquals ||
-      operator == BinaryOperator.greaterThan ||
-      operator == BinaryOperator.greaterThanOrEquals;
+  bool _operatesOnNumbers(BinaryOperator operator) => {
+        BinaryOperator.times,
+        BinaryOperator.modulo,
+        BinaryOperator.lessThan,
+        BinaryOperator.lessThanOrEquals,
+        BinaryOperator.greaterThan,
+        BinaryOperator.greaterThanOrEquals
+      }.contains(operator);
 
   /// Returns true if [node] is entirely composed of number literals and slash
   /// operations.
-  bool _onlySlash(Expression node) {
-    if (node is NumberExpression) return true;
-    if (node is BinaryOperationExpression) {
-      return node.operator == BinaryOperator.dividedBy &&
-          _onlySlash(node.left) &&
-          _onlySlash(node.right);
-    }
-    return false;
-  }
-
-  /// Returns true if [node] is known to always evaluate to a number.
-  bool _isDefinitelyNumber(Expression node) {
-    if (node is NumberExpression) return true;
-    if (node is ParenthesizedExpression) {
-      return _isDefinitelyNumber(node.expression);
-    } else if (node is UnaryOperationExpression) {
-      return _isDefinitelyNumber(node.operand);
-    } else if (node is BinaryOperationExpression) {
-      return _returnsNumbers(node.operator) ||
-          (_isDefinitelyNumber(node.left) && _isDefinitelyNumber(node.right));
-    }
-    return false;
-  }
-
-  /// Returns true if [node] contains a subexpression known to not be a number.
-  bool _isDefinitelyNotNumber(Expression node) {
-    if (node is ParenthesizedExpression) {
-      return _isDefinitelyNotNumber(node.expression);
-    }
-    if (node is BinaryOperationExpression) {
-      return _isDefinitelyNotNumber(node.left) ||
-          _isDefinitelyNotNumber(node.right);
-    }
-    return node is BooleanExpression ||
-        node is ColorExpression ||
-        node is ListExpression ||
-        node is MapExpression ||
-        node is NullExpression ||
-        node is StringExpression;
-  }
+  bool _onlySlash(Expression node) => switch (node) {
+        NumberExpression() => true,
+        BinaryOperationExpression(
+          operator: BinaryOperator.dividedBy,
+          :var left,
+          :var right
+        ) =>
+          _onlySlash(left) && _onlySlash(right),
+        _ => false
+      };
 
   /// Returns true if [node] contains an interpolation.
-  bool _containsInterpolation(Expression node) {
-    if (node is ParenthesizedExpression) {
-      return _containsInterpolation(node.expression);
-    }
-    if (node is BinaryOperationExpression) {
-      return _containsInterpolation(node.left) ||
-          _containsInterpolation(node.right);
-    }
-    return node is StringExpression && node.text.asPlain == null;
-  }
+  bool _containsInterpolation(Expression node) => switch (node) {
+        ParenthesizedExpression(:var expression) ||
+        UnaryOperationExpression(operand: var expression) =>
+          _containsInterpolation(expression),
+        BinaryOperationExpression(:var left, :var right) =>
+          _containsInterpolation(left) || _containsInterpolation(right),
+        StringExpression(text: Interpolation(asPlain: null)) => true,
+        _ => false
+      };
 
   /// Converts a space-separated list [node] to a comma-separated list.
   void _patchSpacesToCommas(ListExpression node) {
@@ -455,14 +457,17 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
   /// Adds patches removing unnecessary parentheses around [node] if it is a
   /// ParenthesizedExpression.
   void _patchParensIfAny(SassNode node) {
-    if (node is! ParenthesizedExpression) return;
-    var expression = node.expression;
-    if (expression is BinaryOperationExpression &&
-        expression.operator == BinaryOperator.dividedBy) {
-      return;
+    switch (node) {
+      case ParenthesizedExpression(
+          expression: BinaryOperationExpression(
+            operator: BinaryOperator.dividedBy
+          )
+        ):
+        return;
+      case ParenthesizedExpression():
+        addPatch(patchDelete(node.span, end: 1));
+        addPatch(patchDelete(node.span, start: node.span.length - 1));
     }
-    addPatch(patchDelete(node.span, end: 1));
-    addPatch(patchDelete(node.span, start: node.span.length - 1));
   }
 
   /// Runs [operation] with the given context.
@@ -482,3 +487,40 @@ class _DivisionMigrationVisitor extends MigrationVisitor {
     _inCalcContext = previousCalcContext;
   }
 }
+
+/// Represents whether an expression is definitely a number, definitely not a
+/// number, or unknown.
+enum _NumberStatus {
+  yes,
+  no,
+  maybe;
+
+  /// Returns [yes] if [node] is definitely a number, [no] if [node] is
+  /// definitely not a number, and [maybe] otherwise.
+  static _NumberStatus of(Expression node) => switch (node) {
+        NumberExpression() ||
+        BinaryOperationExpression(
+          operator: BinaryOperator.times || BinaryOperator.modulo
+        ) =>
+          yes,
+        BooleanExpression() ||
+        ColorExpression() ||
+        ListExpression() ||
+        MapExpression() ||
+        NullExpression() ||
+        StringExpression() =>
+          no,
+        ParenthesizedExpression(:var expression) ||
+        UnaryOperationExpression(operand: var expression) =>
+          of(expression),
+        BinaryOperationExpression(:var left, :var right) => switch ((
+            of(left),
+            of(right)
+          )) {
+            (yes, yes) => yes,
+            (no, _) || (_, no) => no,
+            _ => maybe
+          },
+        _ => maybe,
+      };
+}
diff --git a/lib/src/migrators/media_logic.dart b/lib/src/migrators/media_logic.dart
deleted file mode 100644
index d072713..0000000
--- a/lib/src/migrators/media_logic.dart
+++ /dev/null
@@ -1,57 +0,0 @@
-// Copyright 2022 Google LLC
-//
-// Use of this source code is governed by an MIT-style
-// license that can be found in the LICENSE file or at
-// https://opensource.org/licenses/MIT.
-
-import 'package:sass_api/sass_api.dart';
-import 'package:source_span/source_span.dart';
-
-import '../migration_visitor.dart';
-import '../migrator.dart';
-import '../patch.dart';
-
-/// Migrates deprecated `@media` query syntax to use interpolation.
-class MediaLogicMigrator extends Migrator {
-  final name = 'media-logic';
-  final description = r'Migrates deprecated `@media` query syntax.\n'
-      'See https://sass-lang.com/d/media-logic.';
-
-  /// For each stylesheet URL, the set of relevant spans that require migration.
-  final _expressionsToMigrate = <Uri, Set<FileSpan>>{};
-
-  @override
-  void handleDeprecation(String message, FileSpan? span) {
-    if (span == null) return;
-    if (!message.startsWith('Starting a @media query with ')) return;
-    _expressionsToMigrate.putIfAbsent(span.sourceUrl!, () => {}).add(span);
-  }
-
-  @override
-  Map<Uri, String> migrateFile(
-      ImportCache importCache, Stylesheet stylesheet, Importer importer) {
-    var visitor = _MediaLogicVisitor(
-        importCache, migrateDependencies, _expressionsToMigrate);
-    var result = visitor.run(stylesheet, importer);
-    missingDependencies.addAll(visitor.missingDependencies);
-    return result;
-  }
-}
-
-class _MediaLogicVisitor extends MigrationVisitor {
-  /// For each stylesheet URL, the set of relevant spans that require migration.
-  final Map<Uri, Set<FileSpan>> _expressionsToMigrate;
-
-  _MediaLogicVisitor(ImportCache importCache, bool migrateDependencies,
-      this._expressionsToMigrate)
-      : super(importCache, migrateDependencies);
-
-  @override
-  void beforePatch(Stylesheet node) {
-    var expressions = _expressionsToMigrate[node.span.sourceUrl] ?? {};
-    for (var expression in expressions) {
-      addPatch(Patch.insert(expression.start, '#{'));
-      addPatch(Patch.insert(expression.end, '}'));
-    }
-  }
-}
diff --git a/lib/src/migrators/module.dart b/lib/src/migrators/module.dart
index 76d1513..e1afbf8 100644
--- a/lib/src/migrators/module.dart
+++ b/lib/src/migrators/module.dart
@@ -9,18 +9,17 @@ import 'package:collection/collection.dart';
 import 'package:path/path.dart' as p;
 import 'package:sass_api/sass_api.dart';
 import 'package:source_span/source_span.dart';
-import 'package:tuple/tuple.dart';
 
 import '../exception.dart';
 import '../migration_visitor.dart';
 import '../migrator.dart';
 import '../patch.dart';
 import '../utils.dart';
+import '../util/member_declaration.dart';
 import '../util/node_modules_importer.dart';
 
 import 'module/built_in_functions.dart';
 import 'module/forward_type.dart';
-import 'module/member_declaration.dart';
 import 'module/reference_source.dart';
 import 'module/references.dart';
 import 'module/unreferencable_members.dart';
@@ -117,7 +116,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
   /// Maps canonical URLs to the original URL and importer from the `@import`
   /// rule that last imported that URL.
-  final _originalImports = <Uri, Tuple2<Uri, Importer>>{};
+  final _originalImports = <Uri, (Uri, Importer)>{};
 
   /// Tracks members that are unreferencable in the current scope.
   var _unreferencable = UnreferencableMembers();
@@ -310,24 +309,20 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
     // If entrypoint exposes no members, it should still be forwarded to ensure
     // that the import-only file still includes its CSS.
-    var dependency =
-        _absoluteUrlToDependency(entrypoint, relativeTo: importOnlyUrl).item1;
+    var (dependency, _) =
+        _absoluteUrlToDependency(entrypoint, relativeTo: importOnlyUrl);
     var forwards = forwardsByUrl.remove(entrypoint);
     var entrypointForwards = forwards != null
         ? _forwardRulesForShown(entrypoint, '"$dependency"', forwards, {})
         : ['@forward "$dependency"'];
-    var tuples = [
-      for (var entry in forwardsByUrl.entries)
-        Tuple3(
-            entry.key,
-            _absoluteUrlToDependency(entry.key, relativeTo: importOnlyUrl)
-                .item1,
-            entry.value)
-    ];
     var forwardLines = [
-      for (var tuple in tuples)
-        ..._forwardRulesForShown(tuple.item1, '"${tuple.item2}"', tuple.item3,
-            hiddenByUrl[tuple.item1] ?? {}),
+      for (var MapEntry(key: url, value: shownByPrefix)
+          in forwardsByUrl.entries)
+        ..._forwardRulesForShown(
+            url,
+            '"${_absoluteUrlToDependency(url, relativeTo: importOnlyUrl).$1}"',
+            shownByPrefix,
+            hiddenByUrl[url] ?? {}),
       ...entrypointForwards
     ];
     var semicolon = entrypoint.path.endsWith('.sass') ? '' : ';';
@@ -378,10 +373,9 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
         .map((declaration) => declaration.sourceUrl)
         .toSet()) {
       if (url == currentUrl || _forwardedUrls.contains(url)) continue;
-      var forwards =
-          _makeForwardRules(url, '"${_absoluteUrlToDependency(url).item1}"');
+      var (ruleUrl, isRelative) = _absoluteUrlToDependency(url);
+      var forwards = _makeForwardRules(url, '"$ruleUrl"');
       if (forwards == null) continue;
-      var isRelative = _absoluteUrlToDependency(url).item2;
       (isRelative ? relativeForwards : loadPathForwards)
           .addAll([for (var rule in forwards) '$rule$semicolon\n']);
     }
@@ -407,7 +401,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
         importCache
                 .canonicalize(rule.url,
                     baseImporter: importer, baseUrl: node.span.sourceUrl)
-                ?.item2 ??
+                ?.$2 ??
             rule.url: rule.namespace
     };
     _determineNamespaces(node.span.sourceUrl!, _namespaces);
@@ -511,7 +505,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     var ruleUrlsForSources = {
       for (var source in sources.whereType<ImportSource>())
         source: source.originalRuleUrl ??
-            _absoluteUrlToDependency(source.url, relativeTo: currentUrl).item1
+            _absoluteUrlToDependency(source.url, relativeTo: currentUrl).$1
     };
     // Then handle `@import` rules, in order of path segment count.
     for (var sources in _orderSources(ruleUrlsForSources)) {
@@ -593,10 +587,10 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
   /// Visits [children] with a new scope for tracking unreferencable members.
   @override
-  void visitChildren(List<Statement> children) {
+  void visitChildren(List<Statement> children, {bool withScope = true}) {
     var oldUnreferencable = _unreferencable;
     _unreferencable = UnreferencableMembers(_unreferencable);
-    super.visitChildren(children);
+    super.visitChildren(children, withScope: withScope);
     _unreferencable = oldUnreferencable;
   }
 
@@ -753,10 +747,8 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   /// `meta.load-css`, or static `@import` rules
   @override
   void visitImportRule(ImportRule node) {
-    var imports =
+    var (staticImports, dynamicImports) =
         partitionOnType<Import, StaticImport, DynamicImport>(node.imports);
-    var staticImports = imports.item1;
-    var dynamicImports = imports.item2;
     if (dynamicImports.isEmpty) {
       _useAllowed = false;
       return;
@@ -769,22 +761,20 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
     for (var import in dynamicImports) {
       Uri? ruleUrl = import.url;
-      var tuple = importCache.canonicalize(ruleUrl,
-          baseImporter: importer, baseUrl: currentUrl, forImport: true);
-      var canonicalImport = tuple?.item2;
-      if (canonicalImport != null &&
-          references.orphanImportOnlyFiles.containsKey(canonicalImport)) {
+      if (importCache.canonicalize(ruleUrl,
+              baseImporter: importer, baseUrl: currentUrl, forImport: true)
+          case (var newImporter, var canonicalImport, originalUrl: _)?
+          when references.orphanImportOnlyFiles.containsKey(canonicalImport)) {
         ruleUrl = null;
-        var url = references.orphanImportOnlyFiles[canonicalImport]?.url;
-        if (url != null && tuple != null) {
-          var canonicalRedirect = importCache
-              .canonicalize(url,
-                  baseImporter: tuple.item1, baseUrl: canonicalImport)!
-              .item2;
-          ruleUrl = _absoluteUrlToDependency(canonicalRedirect).item1;
+        if (references.orphanImportOnlyFiles[canonicalImport]
+            case ForwardRule(:var url)) {
+          if (importCache.canonicalize(url,
+                  baseImporter: newImporter, baseUrl: canonicalImport)
+              case (_, var canonicalRedirect, originalUrl: _)?) {
+            (ruleUrl, _) = _absoluteUrlToDependency(canonicalRedirect);
+          }
         }
       }
-
       if (ruleUrl != null) {
         if (_useAllowed) {
           migratedRules.addAll(_migrateImportToRules(ruleUrl, import.span));
@@ -829,10 +819,8 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   /// corresponding regular file. This allows imports of import-only files that
   /// redirect to a different path to be migrated in-place.
   List<String> _migrateImportToRules(Uri ruleUrl, FileSpan context) {
-    var tuple = _migrateImportCommon(ruleUrl, context);
-    var canonicalUrl = tuple.item1;
-    var config = tuple.item2;
-    var forwardForConfig = tuple.item3;
+    var (canonicalUrl, config, forwardForConfig) =
+        _migrateImportCommon(ruleUrl, context);
 
     var asClause = '';
     var defaultNamespace = namespaceForPath(ruleUrl.path);
@@ -879,10 +867,9 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
       _unreferencable.add(declaration, UnreferencableType.fromImporter);
     }
 
-    var tuple = _migrateImportCommon(ruleUrl, context);
-    var canonicalUrl = tuple.item1;
-    var config = tuple.item2;
-    if (tuple.item3 != null) {
+    var (canonicalUrl, config, forwardForConfig) =
+        _migrateImportCommon(ruleUrl, context);
+    if (forwardForConfig != null) {
       throw MigrationSourceSpanException(
           "This declaration attempts to override a default value in an "
           "indirect, nested import of ${p.prettyUri(canonicalUrl)}, which is "
@@ -912,8 +899,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   /// `meta.load-css`. The third is a string of variables that should be added
   /// to a `show` clause of a `@forward` rule so that they can be configured by
   /// an upstream file.
-  Tuple3<Uri, String?, String?> _migrateImportCommon(
-      Uri ruleUrl, FileSpan context) {
+  (Uri, String?, String?) _migrateImportCommon(Uri ruleUrl, FileSpan context) {
     var oldConfiguredVariables = __configuredVariables;
     __configuredVariables = {};
     _upstreamStylesheets.add(currentUrl);
@@ -930,9 +916,8 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
     // Associate the importer for this URL with the resolved URL so that we can
     // re-use this import URL later on.
-    var canonicalUrl = tuple.item2;
-    _originalImports.putIfAbsent(
-        canonicalUrl, () => Tuple2(ruleUrl, tuple.item1));
+    var canonicalUrl = tuple.$2;
+    _originalImports.putIfAbsent(canonicalUrl, () => (ruleUrl, tuple.$1));
 
     // Pass the variables that were configured by the importing file to `with`,
     // and forward the rest and add them to `oldConfiguredVariables` because
@@ -990,7 +975,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     } else if (configured.isNotEmpty) {
       normalConfig = "(\n  " + configured.join(',\n  ') + "\n)";
     }
-    return Tuple3(canonicalUrl, normalConfig, extraForward);
+    return (canonicalUrl, normalConfig, extraForward);
   }
 
   /// If [url] contains any member declarations that should be forwarded from
@@ -1115,7 +1100,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   void visitUseRule(UseRule node) {
     _usedUrls.add(importCache
             .canonicalize(node.url, baseImporter: importer, baseUrl: currentUrl)
-            ?.item2 ??
+            ?.$2 ??
         node.url);
   }
 
@@ -1126,7 +1111,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   void visitForwardRule(ForwardRule node) {
     _forwardedUrls.add(importCache
             .canonicalize(node.url, baseImporter: importer, baseUrl: currentUrl)
-            ?.item2 ??
+            ?.$2 ??
         node.url);
   }
 
@@ -1249,8 +1234,8 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     }
     if (!_usedUrls.contains(url)) {
       // Add new `@use` rule for indirect dependency
-      var tuple = _absoluteUrlToDependency(url);
-      var defaultNamespace = namespaceForPath(tuple.item1.path);
+      var (dependency, isRelative) = _absoluteUrlToDependency(url);
+      var defaultNamespace = namespaceForPath(dependency.path);
       // There are a few edge cases where the reference in [declaration] wasn't
       // tracked by [references.sources], so we add a namespace with simple
       // conflict resolution if one for this URL doesn't already exist.
@@ -1259,8 +1244,8 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
       var namespace = _namespaces[url];
       var asClause = defaultNamespace == namespace ? '' : ' as $namespace';
       _usedUrls.add(url);
-      (tuple.item2 ? _additionalRelativeUseRules : _additionalLoadPathUseRules)
-          .add('@use "${tuple.item1}"$asClause');
+      (isRelative ? _additionalRelativeUseRules : _additionalLoadPathUseRules)
+          .add('@use "$dependency"$asClause');
     }
     return _namespaces[url];
   }
@@ -1272,11 +1257,10 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   /// The first item of the returned tuple is the dependency, the second item
   /// is true when this dependency is resolved relative to the current URL and
   /// false when it's resolved relative to a load path.
-  Tuple2<Uri, bool> _absoluteUrlToDependency(Uri url, {Uri? relativeTo}) {
+  (Uri, bool) _absoluteUrlToDependency(Uri url, {Uri? relativeTo}) {
     relativeTo ??= currentUrl;
-    var tuple = _originalImports[url];
-    if (tuple != null && tuple.item2 is NodeModulesImporter) {
-      return Tuple2(tuple.item1, false);
+    if (_originalImports[url] case (var url, NodeModulesImporter _)) {
+      return (url, false);
     }
 
     var basename = p.url.basenameWithoutExtension(url.path);
@@ -1298,11 +1282,12 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     ];
     var relativePath = minBy<String, int>(potentialUrls, (url) => url.length)!;
     var isRelative = relativePath == potentialUrls.first;
-    return Tuple2(
-        Uri(
-            path: p.url
-                .relative(p.url.join(p.url.dirname(relativePath), basename))),
-        isRelative);
+    return (
+      Uri(
+          path: p.url
+              .relative(p.url.join(p.url.dirname(relativePath), basename))),
+      isRelative
+    );
   }
 
   /// Returns the longest prefix in [prefixesToRemove] such that [identifier]
diff --git a/lib/src/migrators/module/references.dart b/lib/src/migrators/module/references.dart
index 584b90f..328180e 100644
--- a/lib/src/migrators/module/references.dart
+++ b/lib/src/migrators/module/references.dart
@@ -10,12 +10,13 @@ import 'package:sass_api/sass_api.dart';
 
 import '../../exception.dart';
 import '../../util/bidirectional_map.dart';
+import '../../util/member_declaration.dart';
+import '../../util/scope.dart';
+import '../../util/scoped_ast_visitor.dart';
 import '../../util/unmodifiable_bidirectional_map_view.dart';
 import '../../utils.dart';
 import 'built_in_functions.dart';
-import 'member_declaration.dart';
 import 'reference_source.dart';
-import 'scope.dart';
 
 /// A bidirectional mapping between member declarations and references to those
 /// members.
@@ -167,7 +168,7 @@ class References {
 }
 
 /// A visitor that builds a References object.
-class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
+class _ReferenceVisitor extends ScopedAstVisitor {
   final _variables = BidirectionalMap<VariableExpression, MemberDeclaration>();
   final _variableReassignments = BidirectionalMap<
       MemberDeclaration<VariableDeclaration>, MemberDeclaration>();
@@ -183,11 +184,6 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
   final _sources = <SassReference, ReferenceSource>{};
   final _orphanImportOnlyFiles = <Uri, ForwardRule?>{};
 
-  /// The current global scope.
-  ///
-  /// This persists across imports, but not across module loads.
-  late Scope _scope;
-
   /// Mapping from canonical stylesheet URLs to the global scope of the module
   /// contained within it.
   ///
@@ -251,22 +247,22 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
   /// [importer]) and its dependencies.
   References build(Stylesheet stylesheet, Importer importer) {
     _importer = importer;
-    _scope = Scope();
+    currentScope = Scope();
     _currentUrl = stylesheet.span.sourceUrl!;
     _isOrphanImportOnly = isImportOnlyFile(_currentUrl);
-    _moduleScopes[_currentUrl] = _scope;
+    _moduleScopes[_currentUrl] = currentScope;
     _declarationSources = {};
     _moduleSources[_currentUrl] = _declarationSources;
     visitStylesheet(stylesheet);
 
-    for (var variable in _scope.variables.values) {
+    for (var variable in currentScope.variables.values) {
       var original = _variableReassignments[variable] ?? variable;
       _globalDeclarations.add(original);
       _globalDeclarations.addAll(_variableReassignments.keysForValue(original));
     }
-    _globalDeclarations.addAll(_scope.mixins.values);
-    _globalDeclarations.addAll(_scope.functions.values);
-    _checkUnresolvedReferences(_scope);
+    _globalDeclarations.addAll(currentScope.mixins.values);
+    _globalDeclarations.addAll(currentScope.functions.values);
+    _checkUnresolvedReferences(currentScope);
     _resolveBuiltInFunctionReferences();
     return References._(
         _variables,
@@ -325,7 +321,7 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
     _namespaces = {};
     _currentUrl = node.span.sourceUrl!;
     _isOrphanImportOnly = isImportOnlyFile(_currentUrl);
-    super.visitChildren(node.children);
+    super.visitChildren(node.children, withScope: false);
     if (_isOrphanImportOnly) {
       _orphanImportOnlyFiles[_currentUrl] =
           _lastRegularForward?.span.sourceUrl == _currentUrl
@@ -350,17 +346,18 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
             "Could not find Sass file at '${p.prettyUri(import.url)}'.",
             import.span);
       }
+      var (newImporter, stylesheet) = result;
 
       var oldImporter = _importer;
-      _importer = result.item1;
+      _importer = newImporter;
       var oldLibraryUrl = _libraryUrl;
-      var url = result.item2.span.sourceUrl!;
+      var url = stylesheet.span.sourceUrl!;
       if (_importer != oldImporter && !isImportOnlyFile(url)) {
         _libraryUrl ??= url;
       }
       var oldRuleUrl = _currentRuleUrl;
       _currentRuleUrl = import.url;
-      visitStylesheet(result.item2);
+      visitStylesheet(stylesheet);
       var importSource = ImportSource(url, import);
       for (var entry in _declarationSources.entries.toList()) {
         var declaration = entry.key;
@@ -415,28 +412,28 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
           "Could not find Sass file at '${p.prettyUri(ruleUrl)}'.",
           nodeForSpan.span);
     }
+    var (newImporter, stylesheet) = result;
 
-    var stylesheet = result.item2;
     var canonicalUrl = stylesheet.span.sourceUrl!;
     if (_moduleScopes.containsKey(canonicalUrl)) return canonicalUrl;
 
-    var oldScope = _scope;
-    _scope = Scope();
-    _moduleScopes[canonicalUrl] = _scope;
+    var oldScope = currentScope;
+    currentScope = Scope();
+    _moduleScopes[canonicalUrl] = currentScope;
     var oldSources = _declarationSources;
     _declarationSources = {};
     _moduleSources[canonicalUrl] = _declarationSources;
     var oldImporter = _importer;
-    _importer = result.item1;
+    _importer = newImporter;
     var oldLibraryUrl = _libraryUrl;
     _libraryUrl = null;
     var oldRuleUrl = _currentRuleUrl;
     _currentRuleUrl = ruleUrl;
     visitStylesheet(stylesheet);
-    _checkUnresolvedReferences(_scope);
+    onScopeClose();
     _libraryUrl = oldLibraryUrl;
     _importer = oldImporter;
-    _scope = oldScope;
+    currentScope = oldScope;
     _declarationSources = oldSources;
     _currentRuleUrl = oldRuleUrl;
     return canonicalUrl;
@@ -462,19 +459,19 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
       }
       if (_visibleThroughForward(declaration.name, node.prefix,
           node.shownVariables, node.hiddenVariables)) {
-        _forwardMember(declaration, node, canonicalUrl, _scope.variables);
+        _forwardMember(declaration, node, canonicalUrl, currentScope.variables);
       }
     }
     for (var declaration in moduleScope.mixins.values) {
       if (_visibleThroughForward(declaration.name, node.prefix,
           node.shownMixinsAndFunctions, node.hiddenMixinsAndFunctions)) {
-        _forwardMember(declaration, node, canonicalUrl, _scope.mixins);
+        _forwardMember(declaration, node, canonicalUrl, currentScope.mixins);
       }
     }
     for (var declaration in moduleScope.functions.values) {
       if (_visibleThroughForward(declaration.name, node.prefix,
           node.shownMixinsAndFunctions, node.hiddenMixinsAndFunctions)) {
-        _forwardMember(declaration, node, canonicalUrl, _scope.functions);
+        _forwardMember(declaration, node, canonicalUrl, currentScope.functions);
       }
     }
   }
@@ -513,31 +510,10 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
     }
   }
 
-  /// Visits each of [node]'s expressions and children.
-  ///
-  /// All of [node]'s arguments are declared as local variables in a new scope.
-  @override
-  void visitCallableDeclaration(CallableDeclaration node) {
-    var oldScope = _scope;
-    _scope = Scope(_scope);
-    for (var argument in node.arguments.arguments) {
-      _scope.variables[argument.name] = MemberDeclaration(argument);
-      var defaultValue = argument.defaultValue;
-      if (defaultValue != null) visitExpression(defaultValue);
-    }
-    super.visitChildren(node.children);
-    _checkUnresolvedReferences(_scope);
-    _scope = oldScope;
-  }
-
-  /// Visits [children] with a local scope.
+  /// Check any unresolved references each time a scope is closed.
   @override
-  void visitChildren(List<Statement> children) {
-    var oldScope = _scope;
-    _scope = Scope(_scope);
-    super.visitChildren(children);
-    _checkUnresolvedReferences(_scope);
-    _scope = oldScope;
+  void onScopeClose() {
+    _checkUnresolvedReferences(currentScope);
   }
 
   /// Finds any declarations in [scope] that match one of the references in
@@ -593,12 +569,14 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
   /// If [namespace] is null or does not exist within this stylesheet, this
   /// returns the current stylesheet's scope.
   Scope _scopeForNamespace(String? namespace) =>
-      _moduleScopes[_namespaces[namespace]] ?? _scope;
+      _moduleScopes[_namespaces[namespace]] ?? currentScope;
 
   /// Declares a variable in the current scope.
   @override
   void visitVariableDeclaration(VariableDeclaration node) {
-    super.visitVariableDeclaration(node);
+    // Visit expression directly so we can bypass ScopedAstVisitor adding this
+    // declaration and handle it ourselves.
+    visitExpression(node.expression);
     var member = MemberDeclaration(node);
     _declarationSources[member] = CurrentSource(_currentUrl);
     _registerLibraryUrl(member);
@@ -641,7 +619,7 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
       var source = _declarationSources[declaration];
       if (source != null) _sources[node] = source;
     } else if (namespace == null) {
-      _unresolvedReferences[node] = _scope;
+      _unresolvedReferences[node] = currentScope;
     }
   }
 
@@ -652,7 +630,6 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
     var member = MemberDeclaration(node);
     _declarationSources[member] = CurrentSource(_currentUrl);
     _registerLibraryUrl(member);
-    _scope.mixins[node.name] = member;
   }
 
   /// Visits an `@include` rule, storing the mixin reference.
@@ -670,7 +647,7 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
       _mixins[node] = declaration;
       _sources[node] = _declarationSources[declaration]!;
     } else if (namespace == null) {
-      _unresolvedReferences[node] = _scope;
+      _unresolvedReferences[node] = currentScope;
     }
   }
 
@@ -681,7 +658,6 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
     var member = MemberDeclaration(node);
     _declarationSources[member] = CurrentSource(_currentUrl);
     _registerLibraryUrl(member);
-    _scope.functions[node.name] = member;
   }
 
   /// Visits a function call, storing it if it is a user-defined function.
@@ -703,7 +679,7 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
       if (node.name == 'get-function') {
         _sources[node] = BuiltInSource("meta");
       } else {
-        _unresolvedReferences[node] = _scope;
+        _unresolvedReferences[node] = currentScope;
         return;
       }
     }
@@ -718,7 +694,7 @@ class _ReferenceVisitor with RecursiveStatementVisitor, RecursiveAstVisitor {
     if (declaration != null && !_fromForwardRuleInCurrent(declaration)) {
       _getFunctionReferences[node] = declaration;
     } else if (namespace == null) {
-      _unresolvedReferences[node] = _scope;
+      _unresolvedReferences[node] = currentScope;
     }
   }
 
diff --git a/lib/src/migrators/module/unreferencable_members.dart b/lib/src/migrators/module/unreferencable_members.dart
index 2c0d190..6a915bd 100644
--- a/lib/src/migrators/module/unreferencable_members.dart
+++ b/lib/src/migrators/module/unreferencable_members.dart
@@ -6,7 +6,7 @@
 
 import 'package:sass_api/sass_api.dart';
 
-import 'member_declaration.dart';
+import '../../util/member_declaration.dart';
 import 'unreferencable_type.dart';
 
 /// Tracks members that are unreferencable in the current scope.
diff --git a/lib/src/runner.dart b/lib/src/runner.dart
index e58631a..e5fd227 100644
--- a/lib/src/runner.dart
+++ b/lib/src/runner.dart
@@ -15,7 +15,6 @@ import 'package:term_glyph/term_glyph.dart' as glyph;
 import 'io.dart';
 import 'migrators/calc_interpolation.dart';
 import 'migrators/division.dart';
-import 'migrators/media_logic.dart';
 import 'migrators/module.dart';
 import 'migrators/namespace.dart';
 import 'migrators/strict_unary.dart';
@@ -57,7 +56,6 @@ class MigratorRunner extends CommandRunner<Map<Uri, String>> {
           help: 'Print the version of the Sass migrator.', negatable: false);
     addCommand(CalculationInterpolationMigrator());
     addCommand(DivisionMigrator());
-    addCommand(MediaLogicMigrator());
     addCommand(ModuleMigrator());
     addCommand(NamespaceMigrator());
     addCommand(StrictUnaryMigrator());
diff --git a/lib/src/migrators/module/member_declaration.dart b/lib/src/util/member_declaration.dart
similarity index 99%
rename from lib/src/migrators/module/member_declaration.dart
rename to lib/src/util/member_declaration.dart
index e744794..22bce60 100644
--- a/lib/src/migrators/module/member_declaration.dart
+++ b/lib/src/util/member_declaration.dart
@@ -7,7 +7,7 @@
 import 'package:path/path.dart' as p;
 import 'package:sass_api/sass_api.dart';
 
-import '../../utils.dart';
+import '../utils.dart';
 
 /// A wrapper class for nodes that declare a variable, function, or mixin.
 class MemberDeclaration<T extends SassDeclaration> {
diff --git a/lib/src/migrators/module/scope.dart b/lib/src/util/scope.dart
similarity index 77%
rename from lib/src/migrators/module/scope.dart
rename to lib/src/util/scope.dart
index 4f89e7f..7a0b50b 100644
--- a/lib/src/migrators/module/scope.dart
+++ b/lib/src/util/scope.dart
@@ -34,6 +34,17 @@ class Scope {
   /// Returns true if this scope is global, and false otherwise.
   bool get isGlobal => parent == null;
 
+  /// The set of all variable names defined in this scope or its ancestors.
+  Set<String> get allVariableNames =>
+      {...variables.keys, ...?parent?.allVariableNames};
+
+  /// The set of all mixin names defined in this scope or its ancestors.
+  Set<String> get allMixinNames => {...mixins.keys, ...?parent?.allMixinNames};
+
+  /// The set of all function names defined in this scope or its ancestors.
+  Set<String> get allFunctionNames =>
+      {...functions.keys, ...?parent?.allFunctionNames};
+
   /// Returns true if this scope is [ancestor] or one of its descendents.
   bool isDescendentOf(Scope ancestor) =>
       this == ancestor || (parent?.isDescendentOf(ancestor) ?? false);
@@ -52,4 +63,6 @@ class Scope {
   /// if it does not.
   MemberDeclaration<FunctionRule>? findFunction(String name) =>
       functions[name] ?? parent?.findFunction(name);
+
+  String toString() => '${functions.keys}->$parent';
 }
diff --git a/lib/src/util/scoped_ast_visitor.dart b/lib/src/util/scoped_ast_visitor.dart
new file mode 100644
index 0000000..a0c2449
--- /dev/null
+++ b/lib/src/util/scoped_ast_visitor.dart
@@ -0,0 +1,102 @@
+// Copyright 2024 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:meta/meta.dart';
+import 'package:sass_api/sass_api.dart';
+
+import 'member_declaration.dart';
+import 'scope.dart';
+
+/// A recursive AST visitor that tracks the Sass members declared in the
+/// current scope.
+abstract class ScopedAstVisitor
+    with RecursiveStatementVisitor, RecursiveAstVisitor {
+  /// The current scope, containing any visible Sass members without a namespace
+  /// to the current point in the AST.
+  ///
+  /// Subclasses that visit multiple modules should update this when changing
+  /// the module being visited.
+  @protected
+  var currentScope = Scope();
+
+  /// A callback called when the visitor closes a local scope.
+  ///
+  /// Subclasses should override this if they need to do something with the
+  /// current local scope before it is closed.
+  @protected
+  void onScopeClose() {}
+
+  /// Evaluates [inScope] in a new child scope of the current scope.
+  @protected
+  void scoped(void Function() inScope) {
+    var oldScope = currentScope;
+    currentScope = Scope(currentScope);
+    inScope();
+    onScopeClose();
+    currentScope = oldScope;
+  }
+
+  @override
+  void visitStylesheet(Stylesheet node) {
+    visitChildren(node.children, withScope: false);
+  }
+
+  /// Visits each child in [children] sequentially.
+  ///
+  /// When [withScope] is true, the children will be visited with a shared
+  /// local scope.
+  @override
+  void visitChildren(List<Statement> children, {bool withScope = true}) {
+    visit() {
+      super.visitChildren(children);
+    }
+
+    return withScope ? scoped(visit) : visit();
+  }
+
+  /// Creates a new child scope, declares [node]'s arguments within it and
+  /// then visits [node]'s children.
+  @override
+  void visitCallableDeclaration(CallableDeclaration node) {
+    scoped(() {
+      for (var argument in node.arguments.arguments) {
+        currentScope.variables[argument.name] = MemberDeclaration(argument);
+        if (argument.defaultValue case var defaultValue?) {
+          visitExpression(defaultValue);
+        }
+      }
+      visitChildren(node.children, withScope: false);
+    });
+  }
+
+  /// Adds [node] to the current scope and then visits it.
+  @override
+  void visitFunctionRule(FunctionRule node) {
+    currentScope.functions[node.name] = MemberDeclaration(node);
+    super.visitFunctionRule(node);
+  }
+
+  /// Adds [node] to the current scope and then visits it.
+  @override
+  void visitMixinRule(MixinRule node) {
+    currentScope.mixins[node.name] = MemberDeclaration(node);
+    super.visitMixinRule(node);
+  }
+
+  /// Visits [node] and then adds it to the current or the global scope.
+  ///
+  /// If [node] is namespaced, no scope will be updated.
+  @override
+  void visitVariableDeclaration(VariableDeclaration node) {
+    super.visitVariableDeclaration(node);
+    var scope = switch (node) {
+      VariableDeclaration(isGlobal: true) => currentScope.global,
+      VariableDeclaration(namespace: null) => currentScope,
+      _ => null
+    };
+    scope?.variables[node.name] = MemberDeclaration(node);
+  }
+}
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index feba634..1c9e9aa 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -7,7 +7,6 @@
 import 'package:charcode/charcode.dart';
 import 'package:sass_api/sass_api.dart';
 import 'package:source_span/source_span.dart';
-import 'package:tuple/tuple.dart';
 
 import 'io.dart';
 import 'patch.dart';
@@ -220,7 +219,7 @@ bool isImportOnlyFile(Uri url) =>
 ///
 /// This asserts that every element in [iterable] is either an `F` or a `G`, and
 /// returns one list containing all the `F`s and one containing all the `G`s.
-Tuple2<List<F>, List<G>> partitionOnType<E, F extends E, G extends E>(
+(List<F>, List<G>) partitionOnType<E, F extends E, G extends E>(
     Iterable<E> iterable) {
   var fs = <F>[];
   var gs = <G>[];
@@ -233,5 +232,5 @@ Tuple2<List<F>, List<G>> partitionOnType<E, F extends E, G extends E>(
     }
   }
 
-  return Tuple2(fs, gs);
+  return (fs, gs);
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index bed5f79..1b919d4 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,10 +1,10 @@
 name: sass_migrator
-version: 1.8.2-dev
+version: 2.0.0
 description: A tool for running migrations on Sass files
 homepage: https://github.com/sass/migrator
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '>=3.0.0 <4.0.0'
 
 dependencies:
   args: ^2.1.0
@@ -17,25 +17,24 @@ dependencies:
   node_interop: ^2.0.2
   node_io: ^2.2.0
   path: ^1.8.0
-  sass_api: ^3.0.4
+  sass_api: ^9.2.7
   source_span: ^1.8.1
   stack_trace: ^1.10.0
   string_scanner: ^1.1.0
   term_glyph: ^1.2.0
-  tuple: ^2.0.0
 
 dev_dependencies:
   archive: ^3.1.2
   cli_pkg: ^2.1.2
   crypto: ^3.0.1
   grinder: ^0.9.0
-  http: ^0.13.1
+  http: ^1.1.2
   node_preamble: ^2.0.0
   pub_semver: ^2.0.0
   test: ^1.17.1
   test_descriptor: ^2.0.0
   test_process: ^2.0.0
-  xml: ^5.1.0
+  xml: ^6.5.0
   yaml: ^3.1.0
 
 executables:
diff --git a/test/migrators/division/calculations.hrx b/test/migrators/division/calculations.hrx
index 6b8c857..7594bd8 100644
--- a/test/migrators/division/calculations.hrx
+++ b/test/migrators/division/calculations.hrx
@@ -1,23 +1,37 @@
 <==> input/entrypoint.scss
+@function sqrt($a) {
+  @return $a;
+}
+
 a {
   $x: 300px;
   $y: 100%;
+  $z: 200;
   b: calc($x / 2);
   c: clamp($x / 10, $y / 4, $x / 2);
   d: min($x / 2, $y / 2);
   e: calc(max($x / 2, $y / 2) / 2);
   f: calc(#{$x / 2});
   g: calc(fn($x / 2));
+  h: sqrt($z / 2);
+  i: log($z / 2);
 }
 
 <==> output/entrypoint.scss
+@function sqrt($a) {
+  @return $a;
+}
+
 a {
   $x: 300px;
   $y: 100%;
+  $z: 200;
   b: calc($x / 2);
   c: clamp($x / 10, $y / 4, $x / 2);
   d: min($x / 2, $y / 2);
   e: calc(max($x / 2, $y / 2) / 2);
   f: calc(#{$x * 0.5});
   g: calc(fn($x * 0.5));
+  h: sqrt($z * 0.5);
+  i: log($z / 2);
 }
diff --git a/test/migrators/media_logic/add_interpolation.hrx b/test/migrators/media_logic/add_interpolation.hrx
deleted file mode 100644
index 0375b89..0000000
--- a/test/migrators/media_logic/add_interpolation.hrx
+++ /dev/null
@@ -1,25 +0,0 @@
-<==> input/entrypoint.scss
-@media (not (foo)) {
-  a {b: c}
-}
-
-@media ((foo) and (bar)) {
-  d {e: f}
-}
-
-@media ((foo) or (bar)) {
-  g {h: i}
-}
-
-<==> output/entrypoint.scss
-@media (#{not (foo)}) {
-  a {b: c}
-}
-
-@media (#{(foo) and (bar)}) {
-  d {e: f}
-}
-
-@media (#{(foo) or (bar)}) {
-  g {h: i}
-}
diff --git a/test/migrators/migrator_dart_test.dart b/test/migrators/migrator_dart_test.dart
index 84fe0e5..8d75fb4 100644
--- a/test/migrators/migrator_dart_test.dart
+++ b/test/migrators/migrator_dart_test.dart
@@ -9,7 +9,6 @@ import '../utils.dart';
 main() {
   testMigrator("calc_interpolation");
   testMigrator("division");
-  testMigrator("media_logic");
   testMigrator("module");
   testMigrator("namespace");
   testMigrator("strict_unary");