no compile-time error for wrong interface methods overriding

[dgrove]

(cloned from issue #970, which reports this issue for the VM)

What steps will reproduce the problem?
consider the following test:
interface I {
  void m1();
}

interface J extends I {
  void m1(int i);
}

main() {
  J j = null;
  try {j.m1(null);} catch (var e) {}
}

What is the expected output? What do you see instead?
Expected: compile-time error
Actual: successful completion

Please provide any additional information below.
co19 tests:
LangSpecTest/08_Interfaces/1/Methods/A03/t01
LangSpecTest/08_Interfaces/1/Methods/A03/t02
LangSpecTest/08_Interfaces/1/Methods/A03/t03
LangSpecTest/08_Interfaces/1/Methods/A03/t04
LangSpecTest/08_Interfaces/1/Methods/A04/t01
LangSpecTest/08_Interfaces/1/Methods/A04/t02
LangSpecTest/08_Interfaces/1/Methods/A04/t03
LangSpecTest/08_Interfaces/1/Methods/A04/t04
LangSpecTest/08_Interfaces/1/Methods/A04/t05

[anders-sandholm]

Removed Area-Frog label.
Added Area-Dart2JS, FromAreaFrog labels.

[kasperl]

I believe dart2js has this problem too.

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Set owner to @peter-ahe-google.
Removed FromAreaFrog label.
Added Accepted label.

[peter-ahe-google]

Removed Priority-Medium label.
Added Priority-High label.

[peter-ahe-google]

Added this to the M1 milestone.

[peter-ahe-google]

Added Started label.

[peter-ahe-google]

I have a preliminary fix here: https://chromiumcodereview.appspot.com/10661029/

Outstanding issues: compiler crashes on cyclic typedefs, the compiler parses class headers twice (this may not be a big deal, actually.

[peter-ahe-google]

This was fixed in r10677.

However, notice that the particular example in the first comment on this bug is a bad test. It assumes that an implementation eagerly load (and validate) classes. I will report this as a bug against the co19 test suite.

dart2js will only validate supertypes of instantiated classes. Long term, dart2js will have an option to validate/compile everything.

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Added Fixed label.