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// Copyright 2012 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 middle::ty;
use syntax::ast;
use syntax::codemap::Span;
use syntax::visit::Visitor;
use syntax::visit;
#[deriving(Clone, Eq)]
enum Context {
Normal, Loop, Closure
}
struct CheckLoopVisitor<'a> {
tcx: &'a ty::ctxt,
}
pub fn check_crate(tcx: &ty::ctxt, krate: &ast::Crate) {
visit::walk_crate(&mut CheckLoopVisitor { tcx: tcx }, krate, Normal)
}
impl<'a> Visitor<Context> for CheckLoopVisitor<'a> {
fn visit_item(&mut self, i: &ast::Item, _cx: Context) {
visit::walk_item(self, i, Normal);
}
fn visit_expr(&mut self, e: &ast::Expr, cx:Context) {
match e.node {
ast::ExprWhile(e, b) => {
self.visit_expr(e, cx);
self.visit_block(b, Loop);
}
ast::ExprLoop(b, _) => {
self.visit_block(b, Loop);
}
ast::ExprFnBlock(_, b) | ast::ExprProc(_, b) => {
self.visit_block(b, Closure);
}
ast::ExprBreak(_) => self.require_loop("break", cx, e.span),
ast::ExprAgain(_) => self.require_loop("continue", cx, e.span),
_ => visit::walk_expr(self, e, cx)
}
}
}
impl<'a> CheckLoopVisitor<'a> {
fn require_loop(&self, name: &str, cx: Context, span: Span) {
match cx {
Loop => {}
Closure => {
self.tcx.sess.span_err(span, format!("`{}` inside of a closure",
name));
}
Normal => {
self.tcx.sess.span_err(span, format!("`{}` outside of loop",
name));
}
}
}
}
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