Always add quotes to attribute selector values that begin with -- (#529)

Closes #527

Author: nex3

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.15.1
+
+* Always add quotes to attribute selector values that begin with `--`, since IE
+  11 doesn't consider them to be identifiers.
+
 ## 1.15.0
 
 * Add support for passing arguments to `@content` blocks. See [the

lib/src/visitor/serialize.dart

@@ -1154,9 +1154,12 @@ class _SerializeVisitor implements CssVisitor, ValueVisitor, SelectorVisitor {
   }
 
   /// Returns whether [text] is a valid identifier.
+  ///
+  /// This *doesn't* consider identifiers beginning with `--` to be valid,
+  /// because IE 11 doesn't.
   bool _isIdentifier(String text) {
     var scanner = StringScanner(text);
-    while (scanner.scanChar($dash)) {}
+    scanner.scanChar($dash);
 
     if (scanner.isDone) return false;
     var first = scanner.readChar();

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.15.0
+version: 1.15.1
 description: A Sass implementation in Dart.
 author: Dart Team <[email protected]>
 homepage: https://github.com/sass/dart-sass