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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::visit;
use syntax::visit::Visitor;
#[deriving(Clone)]
pub struct Context {
in_loop: bool,
can_ret: bool
}
struct CheckLoopVisitor {
tcx: ty::ctxt,
}
pub fn check_crate(tcx: ty::ctxt, crate: &Crate) {
visit::walk_crate(&mut CheckLoopVisitor { tcx: tcx },
crate,
Context { in_loop: false, can_ret: true });
}
impl Visitor<Context> for CheckLoopVisitor {
fn visit_item(&mut self, i:@item, _cx:Context) {
visit::walk_item(self, i, Context {
in_loop: false,
can_ret: true
});
}
fn visit_expr(&mut self, e:@Expr, cx:Context) {
match e.node {
ExprWhile(e, ref b) => {
self.visit_expr(e, cx);
self.visit_block(b, Context { in_loop: true,.. cx });
}
ExprLoop(ref b, _) => {
self.visit_block(b, Context { in_loop: true,.. cx });
}
ExprFnBlock(_, ref b) => {
self.visit_block(b, Context { in_loop: false, can_ret: false });
}
ExprBreak(_) => {
if !cx.in_loop {
self.tcx.sess.span_err(e.span, "`break` outside of loop");
}
}
ExprAgain(_) => {
if !cx.in_loop {
self.tcx.sess.span_err(e.span, "`loop` outside of loop");
}
}
ExprRet(oe) => {
if !cx.can_ret {
self.tcx.sess.span_err(e.span, "`return` in block function");
}
visit::walk_expr_opt(self, oe, cx);
}
_ => visit::walk_expr(self, e, cx)
}
}
}
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