use crate::Registry;
use rustc::middle::cstore::MetadataLoader;
use rustc::session::Session;
+use rustc_errors::struct_span_err;
use rustc_metadata::locator;
-
use rustc_span::symbol::sym;
use rustc_span::Span;
+use syntax::ast::{Crate, Ident};
+
use std::borrow::ToOwned;
use std::env;
use std::mem;
use std::path::PathBuf;
-use syntax::ast::{Crate, Ident};
-use syntax::struct_span_err;
-
-use rustc_error_codes::*;
/// Pointer to a registrar function.
type PluginRegistrarFn = fn(&mut Registry<'_>);