+use rustc_ast::token::{self, Token, TokenKind};
+use rustc_ast::util::comments;
use rustc_data_structures::sync::Lrc;
use rustc_errors::{error_code, DiagnosticBuilder, FatalError};
use rustc_lexer::unescape;
use rustc_session::parse::ParseSess;
use rustc_span::symbol::{sym, Symbol};
use rustc_span::{BytePos, Pos, Span};
-use syntax::token::{self, Token, TokenKind};
-use syntax::util::comments;
use log::debug;
use std::char;