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kallentu/variance_motivation_solution.dart

Last active December 19, 2019 18:33
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variance_motivation_solution.dart
// Add a contravariant variance modifier
class Writer<in T> {
void write(T x) => print(x);
}
main() {
// Compile-time error: The constructor returns type 'Writer<int>'
// that isn't of expected type 'Writer<Object>'.
Writer<Object> objectWriter = Writer<int>();
}
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