+//! The current rustc diagnostics emitter.
+//!
+//! An `Emitter` takes care of generating the output from a `DiagnosticBuilder` struct.
+//!
+//! There are various `Emitter` implementations that generate different output formats such as
+//! JSON and human readable output.
+//!
+//! The output types are defined in `librustc::session::config::ErrorOutputType`.
+
use Destination::*;
use syntax_pos::{SourceFile, Span, MultiSpan};