// interface.
//
+use rustc_ast::ast::{self, GenericArg, Ident};
+use rustc_ast::tokenstream::TokenStream;
use rustc_expand::base::{self, *};
-use syntax::ast::{self, GenericArg, Ident};
-use syntax::symbol::{kw, sym, Symbol};
-use syntax::tokenstream::TokenStream;
-use syntax_pos::Span;
+use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::Span;
use std::env;