83b7cb7ceb
This new pass is run before type checking so that recursive items are detected beforehand. This prevents going into an infinite recursion during type checking when a recursive item is used in an array type. As a bonus, use `span_err` instead of `span_fatal` so multiple errors can be reported. Closes issue #17252
110 lines
3.3 KiB
Rust
110 lines
3.3 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// This compiler pass detects static items that refer to themselves
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// recursively.
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use driver::session::Session;
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use middle::resolve;
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use middle::def::DefStatic;
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use syntax::ast::{Crate, Expr, ExprPath, Item, ItemStatic, NodeId};
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use syntax::{ast_util, ast_map};
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use syntax::visit::Visitor;
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use syntax::visit;
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struct CheckCrateVisitor<'a, 'ast: 'a> {
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sess: &'a Session,
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def_map: &'a resolve::DefMap,
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ast_map: &'a ast_map::Map<'ast>
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}
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impl<'v, 'a, 'ast> Visitor<'v> for CheckCrateVisitor<'a, 'ast> {
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fn visit_item(&mut self, i: &Item) {
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check_item(self, i);
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}
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}
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pub fn check_crate<'ast>(sess: &Session,
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krate: &Crate,
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def_map: &resolve::DefMap,
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ast_map: &ast_map::Map<'ast>) {
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let mut visitor = CheckCrateVisitor {
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sess: sess,
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def_map: def_map,
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ast_map: ast_map
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};
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visit::walk_crate(&mut visitor, krate);
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sess.abort_if_errors();
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}
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fn check_item(v: &mut CheckCrateVisitor, it: &Item) {
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match it.node {
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ItemStatic(_, _, ref ex) => {
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check_item_recursion(v.sess, v.ast_map, v.def_map, it);
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visit::walk_expr(v, &**ex)
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},
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_ => visit::walk_item(v, it)
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}
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}
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struct CheckItemRecursionVisitor<'a, 'ast: 'a> {
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root_it: &'a Item,
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sess: &'a Session,
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ast_map: &'a ast_map::Map<'ast>,
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def_map: &'a resolve::DefMap,
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idstack: Vec<NodeId>
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}
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// Make sure a const item doesn't recursively refer to itself
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// FIXME: Should use the dependency graph when it's available (#1356)
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pub fn check_item_recursion<'a>(sess: &'a Session,
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ast_map: &'a ast_map::Map,
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def_map: &'a resolve::DefMap,
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it: &'a Item) {
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let mut visitor = CheckItemRecursionVisitor {
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root_it: it,
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sess: sess,
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ast_map: ast_map,
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def_map: def_map,
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idstack: Vec::new()
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};
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visitor.visit_item(it);
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}
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impl<'a, 'ast, 'v> Visitor<'v> for CheckItemRecursionVisitor<'a, 'ast> {
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fn visit_item(&mut self, it: &Item) {
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if self.idstack.iter().any(|x| x == &(it.id)) {
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self.sess.span_err(self.root_it.span, "recursive constant");
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return;
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}
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self.idstack.push(it.id);
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visit::walk_item(self, it);
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self.idstack.pop();
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}
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fn visit_expr(&mut self, e: &Expr) {
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match e.node {
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ExprPath(..) => {
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match self.def_map.borrow().find(&e.id) {
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Some(&DefStatic(def_id, _)) if
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ast_util::is_local(def_id) => {
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self.visit_item(&*self.ast_map.expect_item(def_id.node));
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}
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_ => ()
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}
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},
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_ => ()
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}
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visit::walk_expr(self, e);
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}
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}
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