110 lines
3.4 KiB
Rust
110 lines
3.4 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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//! Support for parsing unsupported, old syntaxes, for the purpose of reporting errors. Parsing of
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//! these syntaxes is tested by compile-test/obsolete-syntax.rs.
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//!
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//! Obsolete syntax that becomes too hard to parse can be removed.
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use ast::{Expr, ExprTup};
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use codemap::Span;
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use parse::parser;
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use parse::token;
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use ptr::P;
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/// The specific types of unsupported syntax
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#[derive(Copy, Clone, PartialEq, Eq, Hash)]
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pub enum ObsoleteSyntax {
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ClosureKind,
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ExternCrateString,
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}
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pub trait ParserObsoleteMethods {
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/// Reports an obsolete syntax non-fatal error.
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fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax);
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/// Reports an obsolete syntax non-fatal error, and returns
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/// a placeholder expression
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fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> P<Expr>;
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fn report(&mut self,
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sp: Span,
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kind: ObsoleteSyntax,
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kind_str: &str,
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desc: &str,
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error: bool);
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fn is_obsolete_ident(&mut self, ident: &str) -> bool;
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fn eat_obsolete_ident(&mut self, ident: &str) -> bool;
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}
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impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
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/// Reports an obsolete syntax non-fatal error.
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fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax) {
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let (kind_str, desc, error) = match kind {
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ObsoleteSyntax::ClosureKind => (
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"`:`, `&mut:`, or `&:`",
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"rely on inference instead",
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true,
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),
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ObsoleteSyntax::ExternCrateString => (
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"\"crate-name\"",
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"use an identifier not in quotes instead",
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false, // warning for now
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),
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};
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self.report(sp, kind, kind_str, desc, error);
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}
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/// Reports an obsolete syntax non-fatal error, and returns
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/// a placeholder expression
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fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> P<Expr> {
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self.obsolete(sp, kind);
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self.mk_expr(sp.lo, sp.hi, ExprTup(vec![]))
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}
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fn report(&mut self,
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sp: Span,
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kind: ObsoleteSyntax,
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kind_str: &str,
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desc: &str,
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error: bool) {
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if error {
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self.span_err(sp, &format!("obsolete syntax: {}", kind_str));
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} else {
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self.span_warn(sp, &format!("obsolete syntax: {}", kind_str));
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}
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if !self.obsolete_set.contains(&kind) {
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self.sess
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.span_diagnostic
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.handler()
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.note(&format!("{}", desc));
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self.obsolete_set.insert(kind);
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}
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}
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fn is_obsolete_ident(&mut self, ident: &str) -> bool {
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match self.token {
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token::Ident(sid, _) => {
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token::get_ident(sid) == ident
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}
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_ => false
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}
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}
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fn eat_obsolete_ident(&mut self, ident: &str) -> bool {
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if self.is_obsolete_ident(ident) {
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self.bump();
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true
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} else {
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false
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}
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}
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}
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