Wrong analyzer error message when unnamed constructor returns wrong type

[sgrekhov]

The code is the following:

abstract class I<T> {
  factory I() {
    return new C<T>();
  }
}

class C<T> implements I {
}

main() {
  new C();
  new I();
}

Analizer output (in a strong mode) is: [error] The return type 'C<T>' is not a 'I<T>', as defined by the method ''

Note empty method name in an error message. Tested in dartanalyzer version 1.20.0-dev.5.0

[jmesserly]

Thanks for filing this! Referring to the unnamed constructor with '' is confusing.

However it is not a strong mode specific error, so I'm going to adjust the labels.
Here is the non-strong-mode repro:

abstract class I<T> {
  factory I() {
    return new C<T>();
  }
}

class C<T> {
}

main() {
  new C();
  new I();
}

[warning] The return type 'C<T>' is not a 'I<T>', as defined by the method ''.