[]Constant syntax::source_map::SPAN_DEBUG

pub const SPAN_DEBUG: LocalKey<Cell<fn(Span, &mut Formatter) -> Result<(), Error>>>
⚙️ This is an internal compiler API. (rustc_private)

This crate is being loaded from the sysroot, a permanently unstable location for private compiler dependencies. It is not intended for general use. Prefer using a public version of this crate from crates.io via Cargo.toml.