// This pass is supposed to perform only simple checks not requiring name resolution
// or type checking or some other kind of complex analysis.
+use rustc_ast::ast::*;
+use rustc_ast::attr;
+use rustc_ast::expand::is_proc_macro_attr;
+use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
+use rustc_ast::walk_list;
use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{error_code, struct_span_err, Applicability};
use rustc_span::symbol::{kw, sym};
use rustc_span::Span;
use std::mem;
-use syntax::ast::*;
-use syntax::attr;
-use syntax::expand::is_proc_macro_attr;
-use syntax::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
-use syntax::walk_list;
const MORE_EXTERN: &str =
"for more information, visit https://doc.rust-lang.org/std/keyword.extern.html";