Static rustc_errors::TRACK_DIAGNOSTIC

pub static TRACK_DIAGNOSTIC: AtomicRef<fn(_: DiagInner, _: &mut dyn FnMut(DiagInner) -> Option<ErrorGuaranteed>) -> Option<ErrorGuaranteed>>

Diagnostics emitted by DiagCtxtInner::emit_diagnostic are passed through this function. Used for tracking by incremental, to replay diagnostics as necessary.