Fixes #453. Make operator argument covariant
diff --git a/LanguageFeatures/Extension-methods/syntax_covariant_t01.dart b/LanguageFeatures/Extension-methods/syntax_covariant_t01.dart
index a057137..3823eaf 100644
--- a/LanguageFeatures/Extension-methods/syntax_covariant_t01.dart
+++ b/LanguageFeatures/Extension-methods/syntax_covariant_t01.dart
@@ -28,7 +28,7 @@
addChild2(A c, [covariant A child]) {} //# 02: compile-time error
addChild3(A c, {covariant A child}) {} //# 03: compile-time error
void set setter (covariant A value) {} //# 04: compile-time error
- C operator+(A other) => this; //# 05: compile-time error
+ C operator+(covariant A other) => this; //# 05: compile-time error
}
main() {
