Provide more context for unenclosed delimiters

* When encountering EOF, point at the last opening brace that does not
   have the same indentation level as its close delimiter.
 * When encountering the wrong type of close delimiter, point at the
   likely correct open delimiter to give a better idea of what went
   wrong.
This commit is contained in:
Esteban Küber 2018-09-04 08:09:49 -07:00
parent 5238b523c3
commit 008aa5a24e
9 changed files with 124 additions and 13 deletions

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@ -66,6 +66,10 @@ pub struct StringReader<'a> {
/// The raw source span which *does not* take `override_span` into account
span_src_raw: Span,
open_braces: Vec<(token::DelimToken, Span)>,
/// The type and spans for all braces that have different indentation.
///
/// Used only for error recovery when arriving to EOF with mismatched braces.
suspicious_open_spans: Vec<(token::DelimToken, Span, Span)>,
crate override_span: Option<Span>,
last_unclosed_found_span: Option<Span>,
}
@ -216,6 +220,7 @@ impl<'a> StringReader<'a> {
span: syntax_pos::DUMMY_SP,
span_src_raw: syntax_pos::DUMMY_SP,
open_braces: Vec::new(),
suspicious_open_spans: Vec::new(),
override_span,
last_unclosed_found_span: None,
}

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@ -52,6 +52,20 @@ impl<'a> StringReader<'a> {
err.span_label(sp, "un-closed delimiter");
}
if let Some((delim, _)) = self.open_braces.last() {
if let Some((d, open_sp, close_sp)) = self.suspicious_open_spans.iter()
.filter(|(d, _, _)| delim == d)
.next() // these are in reverse order as they get inserted on close, but
{ // we want the last open/first close
if d == delim {
err.span_label(*open_sp, "this might be the culprit...");
err.span_label(
*close_sp,
"...as it matches this but it has different indentation",
);
}
}
}
Err(err)
},
token::OpenDelim(delim) => {
@ -70,11 +84,20 @@ impl<'a> StringReader<'a> {
// Expand to cover the entire delimited token tree
let span = pre_span.with_hi(self.span.hi());
let sm = self.sess.source_map();
match self.token {
// Correct delimiter.
token::CloseDelim(d) if d == delim => {
self.open_braces.pop().unwrap();
let (open_brace, open_brace_span) = self.open_braces.pop().unwrap();
if let Some(current_padding) = sm.span_to_margin(self.span) {
if let Some(padding) = sm.span_to_margin(open_brace_span) {
if current_padding != padding {
self.suspicious_open_spans.push(
(open_brace, open_brace_span, self.span),
);
}
}
}
// Parse the close delimiter.
self.real_token();
}
@ -96,6 +119,19 @@ impl<'a> StringReader<'a> {
if let Some(&(_, sp)) = self.open_braces.last() {
err.span_label(sp, "un-closed delimiter");
};
if let Some(current_padding) = sm.span_to_margin(self.span) {
for (brace, brace_span) in &self.open_braces {
if let Some(padding) = sm.span_to_margin(*brace_span) {
// high likelihood of these two corresponding
if current_padding == padding && brace == &other {
err.span_label(
*brace_span,
"close delimiter possibly meant for this",
);
}
}
}
}
err.emit();
}
self.open_braces.pop().unwrap();

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@ -251,17 +251,18 @@ impl SourceMap {
/// crate. The source code of such an "imported source_file" is not available,
/// but we still know enough to generate accurate debuginfo location
/// information for things inlined from other crates.
pub fn new_imported_source_file(&self,
filename: FileName,
name_was_remapped: bool,
crate_of_origin: u32,
src_hash: u128,
name_hash: u128,
source_len: usize,
mut file_local_lines: Vec<BytePos>,
mut file_local_multibyte_chars: Vec<MultiByteChar>,
mut file_local_non_narrow_chars: Vec<NonNarrowChar>)
-> Lrc<SourceFile> {
pub fn new_imported_source_file(
&self,
filename: FileName,
name_was_remapped: bool,
crate_of_origin: u32,
src_hash: u128,
name_hash: u128,
source_len: usize,
mut file_local_lines: Vec<BytePos>,
mut file_local_multibyte_chars: Vec<MultiByteChar>,
mut file_local_non_narrow_chars: Vec<NonNarrowChar>,
) -> Lrc<SourceFile> {
let start_pos = self.next_start_pos();
let end_pos = Pos::from_usize(start_pos + source_len);
@ -578,6 +579,15 @@ impl SourceMap {
.to_string())
}
pub fn span_to_margin(&self, sp: Span) -> Option<usize> {
match self.span_to_prev_source(sp) {
Err(_) => None,
Ok(source) => source.split('\n').last().map(|last_line| {
last_line.len() - last_line.trim_left().len()
})
}
}
/// Return the source snippet as `String` before the given `Span`
pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError> {
self.span_to_source(sp, |src, start_index, _| src[..start_index].to_string())

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@ -3,6 +3,11 @@ error: this file contains an un-closed delimiter
|
LL | trait Foo {
| - un-closed delimiter
LL | fn bar() {
| - this might be the culprit...
...
LL | }
| - ...as it matches this but it has different indentation
...
LL | } //~ ERROR this file contains an un-closed delimiter
| ^

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@ -0,0 +1,32 @@
// Copyright 2018 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.
struct S {
x: [usize; 3],
}
fn foo() {
{
{
println!("hi");
}
}
}
fn main() {
//~^ NOTE un-closed delimiter
{
{
//~^ NOTE this might be the culprit...
foo();
}
//~^ NOTE ...as it matches this but it has different indentation
}
//~ ERROR this file contains an un-closed delimiter

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@ -0,0 +1,17 @@
error: this file contains an un-closed delimiter
--> $DIR/unclosed-braces.rs:32:53
|
LL | fn main() {
| - un-closed delimiter
...
LL | {
| - this might be the culprit...
...
LL | }
| - ...as it matches this but it has different indentation
...
LL | //~ ERROR this file contains an un-closed delimiter
| ^
error: aborting due to previous error

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@ -1,6 +1,8 @@
error: incorrect close delimiter: `}`
--> $DIR/token-error-correct-3.rs:30:9
|
LL | if !is_directory(path.as_ref()) { //~ ERROR: cannot find function `is_directory`
| - close delimiter possibly meant for this
LL | callback(path.as_ref(); //~ ERROR expected one of
| - un-closed delimiter
...

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@ -1,6 +1,8 @@
error: incorrect close delimiter: `}`
--> $DIR/token-error-correct.rs:16:1
|
LL | fn main() {
| - close delimiter possibly meant for this
LL | foo(bar(;
| - un-closed delimiter
LL | //~^ ERROR: expected expression, found `;`

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@ -1,6 +1,8 @@
error: incorrect close delimiter: `}`
--> $DIR/issue-10636-2.rs:18:1
|
LL | pub fn trace_option(option: Option<isize>) {
| - close delimiter possibly meant for this
LL | option.map(|some| 42;
| - un-closed delimiter
...