Use diagnostic code as link to full message

[veber-alex]

fixes #13823 by adding a vscode setting that will keeping the existing diagnostic code and use it as a link to the full compiler error message.
While I was there I also fixed index to fallback to rendered.length to make the previewRustcOutput feature work.

[Veykril]

I'd like to have this message be the default for discoverability purposes. Overall this feature is a hack to get around VSCode's terrible diagnostic UX. So if we could make this a VSCode specific setting that would be the best option right now I think.

[veber-alex]

I added a setting to control the behavior.

[Veykril]

Why exactly was this changed? The regex is meant to stop at the first note:/help: section, there is no = in front of those

[veber-alex]

Hmm, can you give an example of what are you trying to filter out?
I though it was this lines:

error[E0308]: mismatched types
 --> src/main.rs:3:9
  |
2 |     let x = 1;
  |             - expected due to this value
3 |     x = vec![1];
  |         ^^^^^^^ expected integer, found struct `Vec`
  |
  = note: expected type `{integer}`
           found struct `Vec<{integer}>`
  = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)

which have = in front (and 2 spaces).

[Veykril]

error[E0038]: the trait `X` cannot be made into an object
 --> src\main.rs:2:12
  |
2 |     let _: Box<dyn X>;
  |            ^^^^^^^^^^ `X` cannot be made into an object
  |
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
 --> src\main.rs:6:8
  |
5 | trait X {
  |       - this trait cannot be made into an object...
6 |     fn foo() -> Self;
  |        ^^^ ...because associated function `foo` has no `self` parameter
help: consider turning `foo` into a method by giving it a `&self` argument
  |
6 |     fn foo(&self) -> Self;
  |            +++++
help: alternatively, consider constraining `foo` so it does not apply to trait objects
  |
6 |     fn foo() -> Self where Self: Sized;
  |                      +++++++++++++++++

[veber-alex]

Thanks,
I changed the regex back.

[Veykril]

Thanks!
@bors r+

[bors]

📌 Commit ddc0147 has been approved by Veykril

It is now in the queue for this repository.

[bors]

⌛ Testing commit ddc0147 with merge 50801b7...

[bors]

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing 50801b7 to master...