Description Kent Johnson 2007-05-24 11:43:28 EDT

Copied from https://bugs.eclipse.org/bugs/show_bug.cgi?id=166355#c14

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My problem relates to calls to super(), where the call is ambiguous due to generics.  Consider the classes:

public class SuperClass<T> {
  public SuperClass(String _arg1) {
    System.out.println("String");
  }

  public SuperClass(T _arg1) {
   System.out.println("T");
  }
}

class SubClass<T> extends SuperClass<T> {
  public SubClass(String _arg1) {
    super(_arg1);
  }

  public SubClass(T _arg1) {
    super(_arg1);
  }
}

When I invoke "new SubClass<String>("xyz")", which constructor is invoked?
javac takes the position that this is ambiguous, and will actually fail with a
"reference to SuperClass is ambiguous..." message.  It's hard to say, but it
looks like Eclipse resolves this with "Last Match Wins".  That is, it makes a
list of both possible matches, and chooses the "last", based on the order the
constructors appear in the class.  This is not intuitive to me!  However, I
also don't think there exists an intuitive solution to this, and that's why I
feel javac is right here in just not allowing this kind of call.

A related example:
class StringOnlySubClass extends SuperClass<String> {
  public StringOnlySubClass(String _arg1) {
    super(_arg1);
  }
}
In this case, 3.2 appears to use "First Match Wins", and 3.1 uses "Last Match
Wins".

Could this be added as a warning, if not an error?