use rustc::session::parse::feature_err;
use rustc::session::Session;
use rustc::{lint, span_bug, ty};
+use rustc_ast::ast::{self, Ident, NodeId};
use rustc_ast_pretty::pprust;
use rustc_attr::{self as attr, StabilityLevel};
use rustc_data_structures::fx::FxHashSet;
use rustc_span::hygiene::{self, ExpnData, ExpnId, ExpnKind};
use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::{Span, DUMMY_SP};
-use syntax::ast::{self, Ident, NodeId};
use rustc_data_structures::sync::Lrc;
use rustc_span::hygiene::{AstPass, MacroKind};