8d27232141
This patch primarily does two things: (1) it prevents lifetimes from
leaking out of unboxed closures; (2) it allows unboxed closure type
notation, call notation, and construction notation to construct closures
matching any of the three traits.
This breaks code that looked like:
let mut f;
{
let x = &5i;
f = |&mut:| *x + 10;
}
Change this code to avoid having a reference escape. For example:
{
let x = &5i;
let mut f; // <-- move here to avoid dangling reference
f = |&mut:| *x + 10;
}
I believe this is enough to consider unboxed closures essentially
implemented. Further issues (for example, higher-rank lifetimes) should
be filed as followups.
Closes #14449.
[breaking-change]
78 lines
2.4 KiB
Rust
78 lines
2.4 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 driver::session::Session;
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::visit::Visitor;
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use syntax::visit;
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#[deriving(Clone, PartialEq)]
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enum Context {
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Normal, Loop, Closure
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}
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struct CheckLoopVisitor<'a> {
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sess: &'a Session,
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}
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pub fn check_crate(sess: &Session, krate: &ast::Crate) {
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visit::walk_crate(&mut CheckLoopVisitor { sess: sess }, krate, Normal)
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}
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impl<'a> Visitor<Context> for CheckLoopVisitor<'a> {
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fn visit_item(&mut self, i: &ast::Item, _cx: Context) {
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visit::walk_item(self, i, Normal);
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}
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fn visit_expr(&mut self, e: &ast::Expr, cx:Context) {
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match e.node {
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ast::ExprWhile(ref e, ref b) => {
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self.visit_expr(&**e, cx);
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self.visit_block(&**b, Loop);
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}
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ast::ExprLoop(ref b, _) => {
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self.visit_block(&**b, Loop);
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}
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ast::ExprForLoop(_, ref e, ref b, _) => {
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self.visit_expr(&**e, cx);
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self.visit_block(&**b, Loop);
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}
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ast::ExprFnBlock(_, _, ref b) |
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ast::ExprProc(_, ref b) |
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ast::ExprUnboxedFn(_, _, _, ref b) => {
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self.visit_block(&**b, Closure);
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}
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ast::ExprBreak(_) => self.require_loop("break", cx, e.span),
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ast::ExprAgain(_) => self.require_loop("continue", cx, e.span),
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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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impl<'a> CheckLoopVisitor<'a> {
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fn require_loop(&self, name: &str, cx: Context, span: Span) {
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match cx {
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Loop => {}
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Closure => {
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self.sess.span_err(span,
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format!("`{}` inside of a closure",
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name).as_slice());
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}
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Normal => {
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self.sess.span_err(span,
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format!("`{}` outside of loop",
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name).as_slice());
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}
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}
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}
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}
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