rust/src/librustc_errors/diagnostic_builder.rs
Manish Goregaokar 937bc2e04a Add approximate suggestions for rustfix
This adds `span_approximate_suggestion()` that lets you emit a
suggestion marked as "approximate" in the JSON output. UI
users see no difference. This is for when rustc and clippy wish to
 emit suggestions which will make sense to the reader (e.g. they may
have placeholders like `<type>`) but are not source-applicable, so that
rustfix/etc can ignore these.

fixes #39254
2018-01-29 11:40:50 +05:30

246 lines
9.5 KiB
Rust

// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use Diagnostic;
use DiagnosticId;
use DiagnosticStyledString;
use Level;
use Handler;
use std::fmt::{self, Debug};
use std::ops::{Deref, DerefMut};
use std::thread::panicking;
use syntax_pos::{MultiSpan, Span};
/// Used for emitting structured error messages and other diagnostic information.
#[must_use]
#[derive(Clone)]
pub struct DiagnosticBuilder<'a> {
pub handler: &'a Handler,
diagnostic: Diagnostic,
}
/// In general, the `DiagnosticBuilder` uses deref to allow access to
/// the fields and methods of the embedded `diagnostic` in a
/// transparent way. *However,* many of the methods are intended to
/// be used in a chained way, and hence ought to return `self`. In
/// that case, we can't just naively forward to the method on the
/// `diagnostic`, because the return type would be a `&Diagnostic`
/// instead of a `&DiagnosticBuilder<'a>`. This `forward!` macro makes
/// it easy to declare such methods on the builder.
macro_rules! forward {
// Forward pattern for &self -> &Self
(pub fn $n:ident(&self, $($name:ident: $ty:ty),*) -> &Self) => {
pub fn $n(&self, $($name: $ty),*) -> &Self {
self.diagnostic.$n($($name),*);
self
}
};
// Forward pattern for &mut self -> &mut Self
(pub fn $n:ident(&mut self, $($name:ident: $ty:ty),*) -> &mut Self) => {
pub fn $n(&mut self, $($name: $ty),*) -> &mut Self {
self.diagnostic.$n($($name),*);
self
}
};
// Forward pattern for &mut self -> &mut Self, with S: Into<MultiSpan>
// type parameter. No obvious way to make this more generic.
(pub fn $n:ident<S: Into<MultiSpan>>(&mut self, $($name:ident: $ty:ty),*) -> &mut Self) => {
pub fn $n<S: Into<MultiSpan>>(&mut self, $($name: $ty),*) -> &mut Self {
self.diagnostic.$n($($name),*);
self
}
};
}
impl<'a> Deref for DiagnosticBuilder<'a> {
type Target = Diagnostic;
fn deref(&self) -> &Diagnostic {
&self.diagnostic
}
}
impl<'a> DerefMut for DiagnosticBuilder<'a> {
fn deref_mut(&mut self) -> &mut Diagnostic {
&mut self.diagnostic
}
}
impl<'a> DiagnosticBuilder<'a> {
/// Emit the diagnostic.
pub fn emit(&mut self) {
if self.cancelled() {
return;
}
self.handler.emit_db(&self);
self.cancel();
}
pub fn is_error(&self) -> bool {
match self.level {
Level::Bug |
Level::Fatal |
Level::PhaseFatal |
Level::Error => {
true
}
Level::Warning |
Level::Note |
Level::Help |
Level::Cancelled => {
false
}
}
}
/// Convenience function for internal use, clients should use one of the
/// span_* methods instead.
pub fn sub<S: Into<MultiSpan>>(
&mut self,
level: Level,
message: &str,
span: Option<S>,
) -> &mut Self {
let span = span.map(|s| s.into()).unwrap_or(MultiSpan::new());
self.diagnostic.sub(level, message, span, None);
self
}
/// Delay emission of this diagnostic as a bug.
///
/// This can be useful in contexts where an error indicates a bug but
/// typically this only happens when other compilation errors have already
/// happened. In those cases this can be used to defer emission of this
/// diagnostic as a bug in the compiler only if no other errors have been
/// emitted.
///
/// In the meantime, though, callsites are required to deal with the "bug"
/// locally in whichever way makes the most sense.
pub fn delay_as_bug(&mut self) {
self.level = Level::Bug;
*self.handler.delayed_span_bug.borrow_mut() = Some(self.diagnostic.clone());
self.cancel();
}
/// Add a span/label to be included in the resulting snippet.
/// This is pushed onto the `MultiSpan` that was created when the
/// diagnostic was first built. If you don't call this function at
/// all, and you just supplied a `Span` to create the diagnostic,
/// then the snippet will just include that `Span`, which is
/// called the primary span.
pub fn span_label<T: Into<String>>(&mut self, span: Span, label: T) -> &mut Self {
self.diagnostic.span_label(span, label);
self
}
forward!(pub fn note_expected_found(&mut self,
label: &fmt::Display,
expected: DiagnosticStyledString,
found: DiagnosticStyledString)
-> &mut Self);
forward!(pub fn note_expected_found_extra(&mut self,
label: &fmt::Display,
expected: DiagnosticStyledString,
found: DiagnosticStyledString,
expected_extra: &fmt::Display,
found_extra: &fmt::Display)
-> &mut Self);
forward!(pub fn note(&mut self, msg: &str) -> &mut Self);
forward!(pub fn span_note<S: Into<MultiSpan>>(&mut self,
sp: S,
msg: &str)
-> &mut Self);
forward!(pub fn warn(&mut self, msg: &str) -> &mut Self);
forward!(pub fn span_warn<S: Into<MultiSpan>>(&mut self, sp: S, msg: &str) -> &mut Self);
forward!(pub fn help(&mut self , msg: &str) -> &mut Self);
forward!(pub fn span_help<S: Into<MultiSpan>>(&mut self,
sp: S,
msg: &str)
-> &mut Self);
forward!(pub fn span_suggestion_short(&mut self,
sp: Span,
msg: &str,
suggestion: String)
-> &mut Self);
forward!(pub fn span_suggestion(&mut self,
sp: Span,
msg: &str,
suggestion: String)
-> &mut Self);
forward!(pub fn span_suggestions(&mut self,
sp: Span,
msg: &str,
suggestions: Vec<String>)
-> &mut Self);
forward!(pub fn span_approximate_suggestion(&mut self,
sp: Span,
msg: &str,
suggestion: String)
-> &mut Self);
forward!(pub fn span_approximate_suggestions(&mut self,
sp: Span,
msg: &str,
suggestions: Vec<String>)
-> &mut Self);
forward!(pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self);
forward!(pub fn code(&mut self, s: DiagnosticId) -> &mut Self);
/// Convenience function for internal use, clients should use one of the
/// struct_* methods on Handler.
pub fn new(handler: &'a Handler, level: Level, message: &str) -> DiagnosticBuilder<'a> {
DiagnosticBuilder::new_with_code(handler, level, None, message)
}
/// Convenience function for internal use, clients should use one of the
/// struct_* methods on Handler.
pub fn new_with_code(handler: &'a Handler,
level: Level,
code: Option<DiagnosticId>,
message: &str)
-> DiagnosticBuilder<'a> {
let diagnostic = Diagnostic::new_with_code(level, code, message);
DiagnosticBuilder::new_diagnostic(handler, diagnostic)
}
/// Creates a new `DiagnosticBuilder` with an already constructed
/// diagnostic.
pub fn new_diagnostic(handler: &'a Handler, diagnostic: Diagnostic)
-> DiagnosticBuilder<'a> {
DiagnosticBuilder { handler, diagnostic }
}
}
impl<'a> Debug for DiagnosticBuilder<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.diagnostic.fmt(f)
}
}
/// Destructor bomb - a `DiagnosticBuilder` must be either emitted or canceled
/// or we emit a bug.
impl<'a> Drop for DiagnosticBuilder<'a> {
fn drop(&mut self) {
if !panicking() && !self.cancelled() {
let mut db = DiagnosticBuilder::new(self.handler,
Level::Bug,
"Error constructed but not emitted");
db.emit();
panic!();
}
}
}