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Rust should suggest single quotes when expecting char #109586
Description
Code
fn convert_c_to_str(c: char) -> &str {
match c {
"A" => "T",
"C" => "G",
"T" => "A",
"G" => "C",
_ => c,
}
}Current output
error[E0308]: mismatched types
--> src/main.rs:4:9
|
3 | match c {
| - this expression has type `char`
4 | "A" => "T",
| ^^^ expected `char`, found `&str`
error[E0308]: mismatched types
--> src/main.rs:5:9
|
3 | match c {
| - this expression has type `char`
4 | "A" => "T",
5 | "C" => "G",
| ^^^ expected `char`, found `&str`
error[E0308]: mismatched types
--> src/main.rs:6:9
|
3 | match c {
| - this expression has type `char`
...
6 | "T" => "A",
| ^^^ expected `char`, found `&str`
error[E0308]: mismatched types
--> src/main.rs:7:9
|
3 | match c {
| - this expression has type `char`
...Desired output
...
"Please use single quotes ('_') to generate chars"
Rationale and extra context
For beginners the error message could be a lot simpler. Sometimes they just want to make a char and using single quotes instead of double quotes is not terribly obvious.
Other cases
No response
Anything else?
No response
Activity
clubby789 commentedon Mar 26, 2023
Both JavaScript and Python have no character type, with
"and'being roughly interchangeable, so this is likely to be a common mistake for newcomers from other languages. Either way, whether it's a typo or a misunderstanding, having an IDE-applicable suggestion will help.Rollup merge of rust-lang#109613 - lukas-code:match-str-to-char-sugge…
Rollup merge of rust-lang#109613 - lukas-code:match-str-to-char-sugge…