Superinterfaces' members with the same name should produce a static warning

[DartBot]

This issue was originally filed by ms...@unipro.ru

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What steps will reproduce the problem?
Run the following test with dartc:

interface SI1 {
  void foo(var v, [int foo, int bar]);
}

interface SI2 {
  void foo(var v, [int foo, int b4r]);
}

interface I extends SI1, SI2 {}

main() {
  I i = null;
  i.foo(null, null, null);
}

What is the expected output? What do you see instead?
According to the section 8.4.1 of the specification: "if there are multiple members m1, …, mk with the same name n that would be inherited (because identically named members existed in several superinterfaces) then at most one member is inherited. If the static types T1, …, Tk of the members m1, …, mk are not identical, then there must be a member mx such that Tx <: Ti, 1 <= x <= k for all i, 1 <= i <= k, or a static type warning occurs."
So, expected result is a static warning, since foo of S1 and foo of S2 have different types and none of them is a subtype of another.
Actual result: dartc does not produce a static warning.

What version of the product are you using? On what operating system?
Dartc, r8088. OS Ubuntu 10.04

Please provide any additional information below.
co19 tests:
Language/08_Interfaces/4_Superinterfaces/1_Inheritance_and_Overriding_A02_t01.dart
Language/08_Interfaces/4_Superinterfaces/1_Inheritance_and_Overriding_A02_t03.dart
Language/08_Interfaces/4_Superinterfaces/1_Inheritance_and_Overriding_A02_t04.dart
 Language/08_Interfaces/4_Superinterfaces/1_Inheritance_and_Overriding_A02_t04.dart

[madsager]

Added Area-Analyzer, Triaged labels.

[danrubel]

Added this to the M1 milestone.

[bwilkerson]

The listed tests are currently passing and there are no tests marked as failing because of this issue.

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Added AssumedStale label.

[DartBot]

This comment was originally written by alexe.kaigorodov@gmail.com

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following tests do not produce any errors both under dart vm and dart analyzer:

/Language/08_Interfaces/5_Superinterfaces/1_Inheritance_and_Overriding_A02_t01.dart
/Language/08_Interfaces/5_Superinterfaces/1_Inheritance_and_Overriding_A02_t02.dart
/Language/08_Interfaces/5_Superinterfaces/1_Inheritance_and_Overriding_A02_t04.dart

[DartBot]

This comment was originally written by rodion...@unipro.ru

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clarification: they're expected to produce static type warnings