Warnings in quoted & spliced code are buggy

[kmcallister]

I'm not sure exactly what's going on but, for example, we missed some deprecation warnings in html5ever, which has #![deny(warnings)]. I've also seen ICEs in the past.

[steveklabnik]

Is this bug still relevant?

[kmcallister]

I believe so, but I don't have clear steps to reproduce :/

[tamird]

Looks like this is not actionable. @steveklabnik close?