The following tests wrongly expect class type arguments to be modified by NNBD_TOP_MERGE: LanguageFeatures/nnbd/overriding/override_checking_A06_t010 LanguageFeatures/nnbd/overriding/override_checking_A06_t011 LanguageFeatures/nnbd/overriding/override_checking_A06_t042 LanguageFeatures/nnbd/overriding/override_checking_A06_t064 LanguageFeatures/nnbd/overriding/override_checking_A06_t068 This has been discussed in https://github.com/dart-lang/sdk/issues/40541 and dart-lang/language#841.