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// Copyright 2012-2014 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.
use self::Context::*;
use rustc::session::Session;
use rustc::dep_graph::DepNode;
use rustc::hir::map::Map;
use rustc::hir::intravisit::{self, Visitor};
use rustc::hir;
use syntax_pos::Span;
#[derive(Clone, Copy, PartialEq)]
enum Context {
Normal,
Loop,
Closure,
}
#[derive(Copy, Clone)]
struct CheckLoopVisitor<'a> {
sess: &'a Session,
cx: Context,
}
pub fn check_crate(sess: &Session, map: &Map) {
let _task = map.dep_graph.in_task(DepNode::CheckLoops);
let krate = map.krate();
krate.visit_all_items(&mut CheckLoopVisitor {
sess: sess,
cx: Normal,
});
}
impl<'a, 'v> Visitor<'v> for CheckLoopVisitor<'a> {
fn visit_item(&mut self, i: &hir::Item) {
self.with_context(Normal, |v| intravisit::walk_item(v, i));
}
fn visit_expr(&mut self, e: &hir::Expr) {
match e.node {
hir::ExprWhile(ref e, ref b, _) => {
self.visit_expr(&e);
self.with_context(Loop, |v| v.visit_block(&b));
}
hir::ExprLoop(ref b, _) => {
self.with_context(Loop, |v| v.visit_block(&b));
}
hir::ExprClosure(_, _, ref b, _) => {
self.with_context(Closure, |v| v.visit_block(&b));
}
hir::ExprBreak(_) => self.require_loop("break", e.span),
hir::ExprAgain(_) => self.require_loop("continue", e.span),
_ => intravisit::walk_expr(self, e),
}
}
}
impl<'a> CheckLoopVisitor<'a> {
fn with_context<F>(&mut self, cx: Context, f: F)
where F: FnOnce(&mut CheckLoopVisitor<'a>)
{
let old_cx = self.cx;
self.cx = cx;
f(self);
self.cx = old_cx;
}
fn require_loop(&self, name: &str, span: Span) {
match self.cx {
Loop => {}
Closure => {
struct_span_err!(self.sess, span, E0267, "`{}` inside of a closure", name)
.span_label(span, &format!("cannot break inside of a closure"))
.emit();
}
Normal => {
struct_span_err!(self.sess, span, E0268, "`{}` outside of loop", name)
.span_label(span, &format!("cannot break outside of a loop"))
.emit();
}
}
}
}
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