0431134119
upgrade the inference based on expected type so that it is able to infer the fn kind in isolation even if the full signature is not available (and we could perhaps do better still in some cases, such as extracting just the types of the arguments but not the return value).
82 lines
2.4 KiB
Rust
82 lines
2.4 KiB
Rust
// Copyright 2012-2014 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 self::Context::*;
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use 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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#[derive(Clone, Copy, PartialEq)]
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enum Context {
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Normal, Loop, Closure
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}
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#[derive(Copy)]
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struct CheckLoopVisitor<'a> {
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sess: &'a Session,
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cx: Context
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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, cx: Normal }, krate)
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}
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impl<'a, 'v> Visitor<'v> for CheckLoopVisitor<'a> {
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fn visit_item(&mut self, i: &ast::Item) {
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self.with_context(Normal, |v| visit::walk_item(v, i));
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}
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fn visit_expr(&mut self, e: &ast::Expr) {
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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);
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self.with_context(Loop, |v| v.visit_block(&**b));
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}
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ast::ExprLoop(ref b, _) => {
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self.with_context(Loop, |v| v.visit_block(&**b));
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}
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ast::ExprClosure(_, _, ref b) => {
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self.with_context(Closure, |v| v.visit_block(&**b));
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}
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ast::ExprBreak(_) => self.require_loop("break", e.span),
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ast::ExprAgain(_) => self.require_loop("continue", e.span),
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_ => visit::walk_expr(self, e)
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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 with_context<F>(&mut self, cx: Context, f: F) where
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F: FnOnce(&mut CheckLoopVisitor<'a>),
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{
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let old_cx = self.cx;
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self.cx = cx;
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f(self);
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self.cx = old_cx;
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}
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fn require_loop(&self, name: &str, span: Span) {
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match self.cx {
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Loop => {}
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Closure => {
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span_err!(self.sess, span, E0267,
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"`{}` inside of a closure", name);
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}
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Normal => {
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span_err!(self.sess, span, E0268,
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"`{}` outside of loop", name);
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}
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}
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}
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}
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