When using `Box<self>` in first method parameter, the error output provides the wrong type in help message

Code

struct Foo {

}
impl Foo {
    fn invoke(Box<self>) -> i32 {
        0
    }
}

fn main() {}

Current output

error: expected one of `:`, `@`, or `|`, found `<`
 --> main.rs:5:18
  |
5 |     fn invoke(Box<self>) -> i32 {
  |                  ^ expected one of `:`, `@`, or `|`
  |
  = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: if this is a `self` type, give it a parameter name
  |
5 |     fn invoke(self: Box<self>) -> i32 {
  |               +++++
help: if this is a type, explicitly ignore the parameter name
  |
5 |     fn invoke(_: Box<self>) -> i32 {
  |               ++

error: aborting due to 1 previous error

Desired output

error: expected one of `:`, `@`, or `|`, found `<`
 --> main.rs:5:18
  |
5 |     fn invoke(Box<self>) -> i32 {
  |                  ^ expected one of `:`, `@`, or `|`
  |
  = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: if this is a `self` type, give it a parameter name
  |
5 |     fn invoke(self: Box<Self>) -> i32 {
  |               +++++
help: if this is a type, explicitly ignore the parameter name
  |
5 |     fn invoke(_: Box<Self>) -> i32 {
  |               ++

error: aborting due to 1 previous error

Rationale and extra context

The type of the parameter in the error message should be uppercase, Box<Self>. However, a lowercase Box<self> is present.

Other cases

No response

Rust Version

$ rustc --version --verbose
rustc 1.80.0-nightly (79734f1db 2024-05-02)
binary: rustc
commit-hash: 79734f1db8dbe322192dea32c0f6b80ab14c4c1d
commit-date: 2024-05-02
host: aarch64-apple-darwin
release: 1.80.0-nightly
LLVM version: 18.1.4

Anything else?

No response

Start by reproducing the example from the issue with rustc and compare the current diagnostic against the desired output. Trace the compiler diagnostic path responsible for the anonymous-parameter help message; done means the suggested type uses uppercase Self in Box<Self> while the rest of the diagnostic remains correct.