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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// This compiler pass detects static items that refer to themselves
// recursively.
use driver::session::Session;
use middle::resolve;
use middle::def::{DefStatic, DefConst};
use syntax::ast;
use syntax::{ast_util, ast_map};
use syntax::visit::Visitor;
use syntax::visit;
struct CheckCrateVisitor<'a, 'ast: 'a> {
sess: &'a Session,
def_map: &'a resolve::DefMap,
ast_map: &'a ast_map::Map<'ast>
}
impl<'v, 'a, 'ast> Visitor<'v> for CheckCrateVisitor<'a, 'ast> {
fn visit_item(&mut self, i: &ast::Item) {
check_item(self, i);
}
}
pub fn check_crate<'ast>(sess: &Session,
krate: &ast::Crate,
def_map: &resolve::DefMap,
ast_map: &ast_map::Map<'ast>) {
let mut visitor = CheckCrateVisitor {
sess: sess,
def_map: def_map,
ast_map: ast_map
};
visit::walk_crate(&mut visitor, krate);
sess.abort_if_errors();
}
fn check_item(v: &mut CheckCrateVisitor, it: &ast::Item) {
match it.node {
ast::ItemStatic(_, _, ref ex) |
ast::ItemConst(_, ref ex) => {
check_item_recursion(v.sess, v.ast_map, v.def_map, it);
visit::walk_expr(v, &**ex)
},
_ => visit::walk_item(v, it)
}
}
struct CheckItemRecursionVisitor<'a, 'ast: 'a> {
root_it: &'a ast::Item,
sess: &'a Session,
ast_map: &'a ast_map::Map<'ast>,
def_map: &'a resolve::DefMap,
idstack: Vec<ast::NodeId>
}
// Make sure a const item doesn't recursively refer to itself
// FIXME: Should use the dependency graph when it's available (#1356)
pub fn check_item_recursion<'a>(sess: &'a Session,
ast_map: &'a ast_map::Map,
def_map: &'a resolve::DefMap,
it: &'a ast::Item) {
let mut visitor = CheckItemRecursionVisitor {
root_it: it,
sess: sess,
ast_map: ast_map,
def_map: def_map,
idstack: Vec::new()
};
visitor.visit_item(it);
}
impl<'a, 'ast, 'v> Visitor<'v> for CheckItemRecursionVisitor<'a, 'ast> {
fn visit_item(&mut self, it: &ast::Item) {
if self.idstack.iter().any(|x| x == &(it.id)) {
self.sess.span_err(self.root_it.span, "recursive constant");
return;
}
self.idstack.push(it.id);
visit::walk_item(self, it);
self.idstack.pop();
}
fn visit_expr(&mut self, e: &ast::Expr) {
match e.node {
ast::ExprPath(..) => {
match self.def_map.borrow().get(&e.id) {
Some(&DefStatic(def_id, _)) |
Some(&DefConst(def_id)) if
ast_util::is_local(def_id) => {
match self.ast_map.get(def_id.node) {
ast_map::NodeItem(item) =>
self.visit_item(item),
ast_map::NodeForeignItem(_) => {},
_ => {
self.sess.span_err(e.span,
format!("expected item, found {}",
self.ast_map.node_to_string(def_id.node)).as_slice());
return;
},
}
}
_ => ()
}
},
_ => ()
}
visit::walk_expr(self, e);
}
}
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