Diagnostics: suggest using `from_str` when calling `parse` on a type that implements `FromStr`

[yoshuawuyts]

Problem

I find myself confusing the parse and from_str methods quite often. Take for example:

error[E0599]: no function or associated item named `parse` found for struct `connection_string::JdbcString` in the current scope
   --> src\connector\mssql.rs:363:55
    |
363 |         let mut jdbc = connection_string::JdbcString::parse(input)?;
    |                                                       ^^^^^ function or associated item not found in `connection_string::JdbcString`

parse doesn't exist on JdbcString; from_str does. So the way to fix it would be to write:

// either call `from_str`
let mut jdbc = connection_string::JdbcString::from_str(input)?;

// or flip it and call `parse` on the string
let mut jdbc: connection_string::JdbcString = input.parse()?;

Solution

It'd be great if the diagnostic could detect if parse was called on a type that implements FromStr and suggest to use from_str instead:

error[E0599]: no function or associated item named `parse` found for struct `connection_string::JdbcString` in the current scope
   --> src\connector\mssql.rs:363:55
    |
363 |         let mut jdbc = connection_string::JdbcString::parse(input)?;
    |                                                       ^^^^^ function or associated item not found in `connection_string::JdbcString`
    |                                                       |
    |                                                       help: did you mean to call `connection_string::JdbcString::from_str`?

[estebank]

I believe that this can be resolved after #120730 by annotating the connection_string::JdbcString::from_str method with #[doc(alias = "parse")] (but that won't work for methods or fields #124273).