76 lines
2.3 KiB
Rust
76 lines
2.3 KiB
Rust
// Copyright 2012 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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use middle::ty;
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use syntax::ast::*;
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use syntax::visit;
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use syntax::visit::Visitor;
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#[deriving(Clone)]
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pub struct Context {
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in_loop: bool,
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can_ret: bool
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}
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struct CheckLoopVisitor {
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tcx: ty::ctxt,
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}
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pub fn check_crate(tcx: ty::ctxt, crate: &Crate) {
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visit::walk_crate(&mut CheckLoopVisitor { tcx: tcx },
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crate,
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Context { in_loop: false, can_ret: true });
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}
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impl Visitor<Context> for CheckLoopVisitor {
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fn visit_item(&mut self, i:@item, _cx:Context) {
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visit::walk_item(self, i, Context {
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in_loop: false,
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can_ret: true
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});
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}
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fn visit_expr(&mut self, e:@Expr, cx:Context) {
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match e.node {
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ExprWhile(e, ref b) => {
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self.visit_expr(e, cx);
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self.visit_block(b, Context { in_loop: true,.. cx });
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}
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ExprLoop(ref b, _) => {
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self.visit_block(b, Context { in_loop: true,.. cx });
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}
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ExprFnBlock(_, ref b) => {
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self.visit_block(b, Context { in_loop: false, can_ret: false });
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}
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ExprBreak(_) => {
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if !cx.in_loop {
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self.tcx.sess.span_err(e.span, "`break` outside of loop");
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}
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}
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ExprAgain(_) => {
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if !cx.in_loop {
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self.tcx.sess.span_err(e.span, "`loop` outside of loop");
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}
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}
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ExprRet(oe) => {
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if !cx.can_ret {
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self.tcx.sess.span_err(e.span, "`return` in block function");
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}
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visit::walk_expr_opt(self, oe, cx);
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}
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_ => visit::walk_expr(self, e, cx)
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}
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}
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}
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