diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6f811082..7923e2610 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 1.42.1
+
+* Fix a bug where Sass variables and function calls in calculations weren't
+  being resolved correctly if there was a parenthesized interpolation elsewhere
+  in the file.
+
 ## 1.42.0
 
 * `min()` and `max()` expressions are once again parsed as calculations as long
diff --git a/lib/src/parse/stylesheet.dart b/lib/src/parse/stylesheet.dart
index d092618d2..afe741594 100644
--- a/lib/src/parse/stylesheet.dart
+++ b/lib/src/parse/stylesheet.dart
@@ -2908,40 +2908,64 @@ abstract class StylesheetParser extends Parser {
     var parens = 0;
     var brackets = <int>[];
 
-    // Scan manually rather than using [scanner] and saving and restoring its
-    // state to avoid the overhead of updating line and column information.
-    var string = scanner.string;
-    for (var i = scanner.position; i < string.length - 1; i++) {
-      var next = string.codeUnitAt(i);
+    var start = scanner.state;
+    while (!scanner.isDone) {
+      var next = scanner.peekChar();
       switch (next) {
         case $backslash:
-          i++;
+          scanner.readChar();
+          scanner.readChar();
+          break;
+
+        case $slash:
+          if (!scanComment()) scanner.readChar();
+          break;
+
+        case $single_quote:
+        case $double_quote:
+          interpolatedString();
           break;
 
         case $hash:
-          if (parens == 0 && string.codeUnitAt(i + 1) == $lbrace) return true;
+          if (parens == 0 && scanner.peekChar(1) == $lbrace) {
+            scanner.state = start;
+            return true;
+          }
+          scanner.readChar();
           break;
 
         case $lparen:
           parens++;
-          continue;
+          continue left;
 
+        left:
         case $lbrace:
         case $lbracket:
-          brackets.add(opposite(next));
+          // dart-lang/sdk#45357
+          brackets.add(opposite(next!));
+          scanner.readChar();
           break;
 
         case $rparen:
           parens--;
-          continue;
+          continue right;
 
+        right:
         case $rbrace:
         case $rbracket:
-          if (brackets.isEmpty || brackets.removeLast() != next) return false;
+          if (brackets.isEmpty || brackets.removeLast() != next) {
+            scanner.state = start;
+            return false;
+          }
+          scanner.readChar();
           break;
+
+        default:
+          scanner.readChar();
       }
     }
 
+    scanner.state = start;
     return false;
   }
 
diff --git a/pkg/sass_api/CHANGELOG.md b/pkg/sass_api/CHANGELOG.md
index 395fcc955..aa34db260 100644
--- a/pkg/sass_api/CHANGELOG.md
+++ b/pkg/sass_api/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.0-beta.13
+
+* No user-visible changes.
+
 ## 1.0.0-beta.12
 
 * No user-visible changes.
diff --git a/pkg/sass_api/pubspec.yaml b/pkg/sass_api/pubspec.yaml
index f9fca7d7d..c8f11412d 100644
--- a/pkg/sass_api/pubspec.yaml
+++ b/pkg/sass_api/pubspec.yaml
@@ -2,7 +2,7 @@ name: sass_api
 # Note: Every time we add a new Sass AST node, we need to bump the *major*
 # version because it's a breaking change for anyone who's implementing the
 # visitor interface(s).
-version: 1.0.0-beta.12
+version: 1.0.0-beta.13
 description: Additional APIs for Dart Sass.
 homepage: https://github.com/sass/dart-sass
 
@@ -10,7 +10,7 @@ environment:
   sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
-  sass: 1.42.0
+  sass: 1.42.1
 
 dependency_overrides:
   sass: {path: ../..}
diff --git a/pubspec.yaml b/pubspec.yaml
index 0cdb0ad00..8e5a7b6a2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: sass
-version: 1.42.0
+version: 1.42.1
 description: A Sass implementation in Dart.
 homepage: https://github.com/sass/dart-sass