What to do when muzzle mismatches occur?

[trask]

A muzzle mismatch isn't really a bad thing. It just shows that instrumentation can't be applied and this is what it is for. Currently we add preconditions to instrumentations when muzzle fails when cross testing. Wondering whether we should bother with this at all.

Originally posted by @laurit in #17306 (comment)

[trask]

I think historically this came from the fact that we emit the muzzle mismatches as WARNINGS (under the debug flag), to make them stand out to users, but it also then causes confusion for users and leads people down the wrong troubleshooting path. And so we added the test failure when cross testing to force us to add the preconditions.

That said, I feel like the muzzle mismatch warnings used to carry their weight in the early days, but I don't recall needing them in a long time now, so I'd be good with bumping them down to DEBUG always and ignoring them in tests.

I thought there was some perf benefit as well? or is that perf benefit already handled by the type instrumentations?