This issue was originally filed by [email protected]

What steps will reproduce the problem?

1. As an example, comment out the "ClassOverrideNegativeTest: Fail" line in test/language/language.status file (only applies to dartc).
2. From the compiler directory run "../tools/build.py --mode debug --arch dartc" then run "../tools/test.py --mode debug --arch dartc".

What is the expected output? What do you see instead?
Dartc generates a warning to stdout about the method override problem. However, it treats it as a warning and produces JS code. For the same file, the VM tries to load the file, reports an error and stops. Effectively, it is as if dartc should have generated a compilation error instead of a warning.

I'd like to get clarity on which violations of the language specification should be errors and which should be warnings.

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