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Rollup merge of #103651 - Alexendoo:parse-format-unicode-escapes, r=wesleywiser

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Fix `rustc_parse_format` spans following escaped utf-8 multibyte chars

Currently too many skips are created for char escapes that are larger than 1 byte when encoded in UTF-8, [playground:](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=c77a9dc669b69b167271b59ed2c8d88c)

```rust
fn main() {
    format!("\u{df}{a}");
    format!("\u{211d}{a}");
    format!("\u{1f4a3}{a}");
}
```
```
error[[E0425]](https://doc.rust-lang.org/stable/error-index.html#E0425): cannot find value `a` in this scope
 --> src/main.rs:2:22
  |
2 |     format!("\u{df}{a}");
  |                      ^ not found in this scope

error[[E0425]](https://doc.rust-lang.org/stable/error-index.html#E0425): cannot find value `a` in this scope
 --> src/main.rs:3:25
  |
3 |     format!("\u{211d}{a}");
  |                         ^ not found in this scope

error[[E0425]](https://doc.rust-lang.org/stable/error-index.html#E0425): cannot find value `a` in this scope
 --> src/main.rs:4:27
  |
4 |     format!("\u{1f4a3}{a}");
  |                           ^ not found in this scope
```

This reduces the number of skips to account for that

Fixes https://github.com/rust-lang/rust-clippy/issues/9727
This commit is contained in:
Dylan DPC 2022-11-08 11:23:51 +05:30 committed by GitHub
commit 4946ee7c8f
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3 changed files with 111 additions and 18 deletions
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47
compiler/rustc_parse_format/src/lib.rs
View File

@ -819,19 +819,19 @@ fn find_skips_from_snippet(
};
fn find_skips(snippet: &str, is_raw: bool) -> Vec<usize> {
let mut s = snippet.char_indices().peekable();
let mut s = snippet.char_indices();
let mut skips = vec![];
while let Some((pos, c)) = s.next() {
match (c, s.peek()) {
match (c, s.clone().next()) {
// skip whitespace and empty lines ending in '\\'
('\\', Some((next_pos, '\n'))) if !is_raw => {
skips.push(pos);
skips.push(*next_pos);
skips.push(next_pos);
let _ = s.next();
while let Some((pos, c)) = s.peek() {
while let Some((pos, c)) = s.clone().next() {
if matches!(c, ' ' | '\n' | '\t') {
skips.push(*pos);
skips.push(pos);
let _ = s.next();
} else {
break;
@ -839,7 +839,7 @@ fn find_skips(snippet: &str, is_raw: bool) -> Vec<usize> {
}
}
('\\', Some((next_pos, 'n' | 't' | 'r' | '0' | '\\' | '\'' | '\"'))) => {
skips.push(*next_pos);
skips.push(next_pos);
let _ = s.next();
}
('\\', Some((_, 'x'))) if !is_raw => {
@ -858,19 +858,30 @@ fn find_skips(snippet: &str, is_raw: bool) -> Vec<usize> {
}
if let Some((next_pos, next_c)) = s.next() {
if next_c == '{' {
skips.push(next_pos);
let mut i = 0; // consume up to 6 hexanumeric chars + closing `}`
while let (Some((next_pos, c)), true) = (s.next(), i < 7) {
if c.is_digit(16) {
skips.push(next_pos);
} else if c == '}' {
skips.push(next_pos);
break;
} else {
break;
}
i += 1;
// consume up to 6 hexanumeric chars
let digits_len =
s.clone().take(6).take_while(|(_, c)| c.is_digit(16)).count();
let len_utf8 = s
.as_str()
.get(..digits_len)
.and_then(|digits| u32::from_str_radix(digits, 16).ok())
.and_then(char::from_u32)
.map_or(1, char::len_utf8);
// Skip the digits, for chars that encode to more than 1 utf-8 byte
// exclude as many digits as it is greater than 1 byte
//
// So for a 3 byte character, exclude 2 digits
let required_skips =
digits_len.saturating_sub(len_utf8.saturating_sub(1));
// skip '{' and '}' also
for pos in (next_pos..).take(required_skips + 2) {
skips.push(pos)
}
s.nth(digits_len);
} else if next_c.is_digit(16) {
skips.push(next_pos);
// We suggest adding `{` and `}` when appropriate, accept it here as if

19
src/test/ui/fmt/unicode-escape-spans.rs Normal file
View File

@ -0,0 +1,19 @@
fn main() {
// 1 byte in UTF-8
format!("\u{000041}{a}"); //~ ERROR cannot find value
format!("\u{0041}{a}"); //~ ERROR cannot find value
format!("\u{41}{a}"); //~ ERROR cannot find value
format!("\u{0}{a}"); //~ ERROR cannot find value
// 2 bytes
format!("\u{0df}{a}"); //~ ERROR cannot find value
format!("\u{df}{a}"); //~ ERROR cannot find value
// 3 bytes
format!("\u{00211d}{a}"); //~ ERROR cannot find value
format!("\u{211d}{a}"); //~ ERROR cannot find value
// 4 bytes
format!("\u{1f4a3}{a}"); //~ ERROR cannot find value
format!("\u{10ffff}{a}"); //~ ERROR cannot find value
}

63
src/test/ui/fmt/unicode-escape-spans.stderr Normal file
View File

@ -0,0 +1,63 @@
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:3:25
|
LL | format!("\u{000041}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:4:23
|
LL | format!("\u{0041}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:5:21
|
LL | format!("\u{41}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:6:20
|
LL | format!("\u{0}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:9:22
|
LL | format!("\u{0df}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:10:21
|
LL | format!("\u{df}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:13:25
|
LL | format!("\u{00211d}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:14:23
|
LL | format!("\u{211d}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:17:24
|
LL | format!("\u{1f4a3}{a}");
| ^ not found in this scope
error[E0425]: cannot find value `a` in this scope
--> $DIR/unicode-escape-spans.rs:18:25
|
LL | format!("\u{10ffff}{a}");
| ^ not found in this scope
error: aborting due to 10 previous errors
For more information about this error, try `rustc --explain E0425`.