Remove `?` from positional arg in implementation function
diff --git a/lib/src/scan.dart b/lib/src/scan.dart
index d7de54d..96fb8ae 100644
--- a/lib/src/scan.dart
+++ b/lib/src/scan.dart
@@ -58,8 +58,10 @@
///
/// If [name] is passed, it's used to describe the expected value if it's not
/// found.
-String expectQuotedString(StringScanner scanner, {String? name}) {
- name ??= 'quoted string';
+String expectQuotedString(
+ StringScanner scanner, {
+ String name = 'quoted string',
+}) {
scanner.expect(_quotedString, name: name);
final string = scanner.lastMatch![0]!;
return string
