@sandersn ,
This is the PR for #30948.
Please give me feedback, regarding the modification.
Thank you.

Seems like the change is probably good. Now run gulp baseline-accept to update the test outputs.

@DanielRosenwasser ,
Thanks a lot for the feedback. I'll run it and update PR.

Actually, I don't know if the change is appropriate because it will error if Omit isn't present. It's not clear if it should. There is a getGlobalTypeOrUndefined.

Mm, team seems to think that maybe we shouldn't even have the fallback.

@DanielRosenwasser ,
I'm sorry that I'm not clear about your comment. Can you please elaborate little bit if possible?

Ok, I can modify the code as follows.

if (! omitTypeAlias) {
  return errorType;
}

return getTypeAliasInstantiation(omitTypeAlias, [source, omitKeyType]);

and get rid of the code from line 4949 to 4955.

All CLA requirements met.

@DanielRosenwasser ,
I changed the code. Can you please give me an insight on how can I fix the tests?
A sample error message is as follows.

The baseline file genericObjectRest.types has changed.
Error: The baseline file genericObjectRest.types has changed

Check out https://github.com/Microsoft/TypeScript/blob/de9b91f46a3fb007812cc9223492226b964f17dd/CONTRIBUTING.md#managing-the-baselines

@DanielRosenwasser ,
Thanks. I fixed the tests\baselines\reference.

@typescript-bot test this

Heya @RyanCavanaugh, I've started to run the extended test suite on this PR at cf15c79. You can monitor the build here. It should now contribute to this PR's status checks.