Wrong type recognizing after null check block

[ChaserVasya]

Snippet

extension NotEmptyOrThrowTExtension<String> on String? {
  String notEmptyOrThrow(Object exception) {
    final self = this;
    if (self == null) {
      throw exception;
    }
    if (self.isEmpty) {
      return self;
    }
    return self;
  }
}

Actual behavior

Expected behavior

isEmpty is recognized.

Version

Dart SDK version: 3.5.4 (stable) (Wed Oct 16 16:18:51 2024 +0000) on "macos_arm64"

[mraleph]

For those curious: extension NotEmptyOrThrowTExtension<String> on String? means that String is actually a type parameter name shadowing String class from dart:core (i.e. it is the same as extension NotEmptyOrThrowTExtension<T> on T?) - hence the error. Removing <String> would fix it.

I think at some point we considered adding code to the analyzer to warn about such shadowing, because people periodically fall into this trap) but probably never got to it.

[eernstg]

https://dart-review.googlesource.com/c/sdk/+/381841 will change avoid_types_as_parameter_names such that this kind of shadowing is reported. Internal code is being adjusted such that the change won't be breaking inside Google.

[ChaserVasya]

I solved this by removing :D
And I close issue