0cdde6e5e0
This commits adds an associated type to the `FromStr` trait representing an error payload for parses which do not succeed. The previous return value, `Option<Self>` did not allow for this form of payload. After the associated type was added, the following attributes were applied: * `FromStr` is now stable * `FromStr::Err` is now stable * `FromStr::from_str` is now stable * `StrExt::parse` is now stable * `FromStr for bool` is now stable * `FromStr for $float` is now stable * `FromStr for $integral` is now stable * Errors returned from stable `FromStr` implementations are stable * Errors implement `Display` and `Error` (both impl blocks being `#[stable]`) Closes #15138
87 lines
2.2 KiB
Rust
87 lines
2.2 KiB
Rust
// Copyright 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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//! Span debugger
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//!
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//! This module shows spans for all expressions in the crate
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//! to help with compiler debugging.
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use std::str::FromStr;
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use ast;
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use diagnostic;
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use visit;
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use visit::Visitor;
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enum Mode {
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Expression,
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Pattern,
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Type,
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}
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impl FromStr for Mode {
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type Err = ();
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fn from_str(s: &str) -> Result<Mode, ()> {
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let mode = match s {
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"expr" => Mode::Expression,
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"pat" => Mode::Pattern,
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"ty" => Mode::Type,
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_ => return Err(())
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};
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Ok(mode)
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}
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}
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struct ShowSpanVisitor<'a> {
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span_diagnostic: &'a diagnostic::SpanHandler,
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mode: Mode,
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}
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impl<'a, 'v> Visitor<'v> for ShowSpanVisitor<'a> {
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fn visit_expr(&mut self, e: &ast::Expr) {
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if let Mode::Expression = self.mode {
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self.span_diagnostic.span_note(e.span, "expression");
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}
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visit::walk_expr(self, e);
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}
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fn visit_pat(&mut self, p: &ast::Pat) {
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if let Mode::Pattern = self.mode {
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self.span_diagnostic.span_note(p.span, "pattern");
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}
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visit::walk_pat(self, p);
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}
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fn visit_ty(&mut self, t: &ast::Ty) {
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if let Mode::Type = self.mode {
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self.span_diagnostic.span_note(t.span, "type");
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}
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visit::walk_ty(self, t);
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}
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fn visit_mac(&mut self, mac: &ast::Mac) {
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visit::walk_mac(self, mac);
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}
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}
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pub fn run(span_diagnostic: &diagnostic::SpanHandler,
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mode: &str,
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krate: &ast::Crate) {
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let mode = match mode.parse().ok() {
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Some(mode) => mode,
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None => return
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};
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let mut v = ShowSpanVisitor {
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span_diagnostic: span_diagnostic,
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mode: mode,
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};
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visit::walk_crate(&mut v, krate);
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}
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