co19/Language/Classes/definition_t23 test fails (to compile with frontend)

[aam]

FAILED: dartk-vm release_x64 co19/Language/Classes/definition_t23
Expected: Pass
Actual: CompileTimeError

--- Command "vm" (took 571ms):
DART_CONFIGURATION=ReleaseX64 xcodebuild/ReleaseX64/dart --dfe=xcodebuild/ReleaseX64/gen/kernel-service.dart.snapshot --kernel-binaries=xcodebuild/ReleaseX64 --ignore-unrecognized-flags --packages=/Users/aam/projects/dart/sdk/.packages /Users/aam/projects/dart/sdk/tests/co19/src/Language/Classes/definition_t23.dart

exit code:
254

stderr:
'file:///Users/aam/projects/dart/sdk/tests/co19/src/Language/Classes/definition_t23.dart': error: line 28 pos 21: super type 'A1' may not be listed in implements clause of class 'I3'
@A() abstract class I3<T> = A1 with B1 implements A1;
                    ^

--- Re-run this test:
python tools/test.py -m release -c dartk co19/Language/Classes/definition_t23

It sounds like a legitimate compilation error though.

[lrhn]

The supertype of I3<T> is A1, and the class also implements A1. The spec does indeed say:

It is a compile-time error if the superclass of a class C is specified as a superinterface of C.

(It should just say "as an interface of C", but otherwise it's pretty clear).

[kmillikin]

So there's a bug in the source-based VM because it's missing the compile time error, and there's a bug in the co19 test itself. But this is not a bug in the front end (nor Analyzer nor dart2js, judging from their co19 status files which all have CompileTimeError).

I filed dart-lang/co19#129 against co19. I assume the issue in the source-based VM will be won't fixed, so I'm not going to file it. (Feel free to file an issue if you disagree.)