suggest using raw string literals when invalid escapes appear

i'd guess about 70% of "bad escape" cases occur when someone meant to
use a raw string literal because they're passing it directly to
Regex::new(). this emits an advisory (Applicability::MaybeIncorrect)
help: suggestion to the user that they use an r"" string,
on top of the normal notes about looking at the
string literal documentation/spec.
This commit is contained in:
Erin Petra Sofiya Moon 2022-02-14 14:21:43 -05:00
parent 52dd59ed21
commit e59cda9ee1
No known key found for this signature in database
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4 changed files with 38 additions and 0 deletions

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@ -185,6 +185,15 @@ pub(crate) fn emit_unescape_error(
version control settings",
);
} else {
if !mode.is_bytes() {
diag.span_suggestion(
span_with_quotes,
"if you meant to write a literal backslash (perhaps escaping in a regular expression), consider a raw string literal",
format!("r\"{}\"", lit),
Applicability::MaybeIncorrect,
);
}
diag.help(
"for more information, visit \
<https://static.rust-lang.org/doc/master/reference.html#literals>",

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@ -17,6 +17,10 @@ LL | '\●'
| ^ unknown character escape
|
= help: for more information, visit <https://static.rust-lang.org/doc/master/reference.html#literals>
help: if you meant to write a literal backslash (perhaps escaping in a regular expression), consider a raw string literal
|
LL | r"\●"
| ~~~~~
error: unknown character escape: `\u{25cf}`
--> $DIR/lex-bad-char-literals-1.rs:14:7
@ -25,6 +29,10 @@ LL | "\●"
| ^ unknown character escape
|
= help: for more information, visit <https://static.rust-lang.org/doc/master/reference.html#literals>
help: if you meant to write a literal backslash (perhaps escaping in a regular expression), consider a raw string literal
|
LL | r"\●"
| ~~~~~
error: aborting due to 4 previous errors

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@ -0,0 +1,7 @@
fn main() {
let ok = r"ab\[c";
let bad = "ab\[c";
//~^ ERROR unknown character escape: `[`
//~| HELP for more information, visit <https://static.rust-lang.org/doc/master/reference.html#literals>
//~| HELP if you meant to write a literal backslash (perhaps escaping in a regular expression), consider a raw string literal
}

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@ -0,0 +1,14 @@
error: unknown character escape: `[`
--> $DIR/bad-escape-suggest-raw-string.rs:3:19
|
LL | let bad = "ab\[c";
| ^ unknown character escape
|
= help: for more information, visit <https://static.rust-lang.org/doc/master/reference.html#literals>
help: if you meant to write a literal backslash (perhaps escaping in a regular expression), consider a raw string literal
|
LL | let bad = r"ab\[c";
| ~~~~~~~~
error: aborting due to previous error