Port the "unconstrained opaque type" diagnostic to using the diagnostic
derive.

Signed-off-by: David Wood <david.wood@huawei.com>

Diagnostics can have multiple primary spans, or have subdiagnostics
repeated at multiple locations, so support `Vec<..>` fields in the
diagnostic derive which become loops in the generated code.

Signed-off-by: David Wood <david.wood@huawei.com>

Currently, the only API for creating errors from a diagnostic derive
will emit it immediately. This makes it difficult to add subdiagnostics
to diagnostics from the derive, so add `create_{err,warning}` functions
that return the diagnostic without emitting it.

Signed-off-by: David Wood <david.wood@huawei.com>

Port the "explicit generic arguments with impl trait" diagnostic to
using the diagnostic derive.

Signed-off-by: David Wood <david.wood@huawei.com>

https://github.com/rust-lang/rust/blob/master/src/librustc_session/lint/builtin.rs
returns page not found.

The following is the background of the move.
First rust-lang#74862 moves from src/librustc_session/lint/builtin.rs
to compiler/rustc_session/src/lint/builtin.rs
Then rust-lang@23018a5 moves from compiler/rustc_session/src/lint/builtin.rs
to compiler/rustc_lint_defs/src/builtin.rs

So, the current correct link is https://github.com/rust-lang/rust/blob/master/compiler/rustc_lint_defs/src/builtin.rs

This PR fixes a broken link on the following page:
https://doc.rust-lang.org/beta/unstable-book/language-features/plugin.html

make Size and Align debug-printing a bit more compact

In particular in `{:#?}`-mode, these take up a lot of space, so I think this is the better alternative (even though it is a bit longer in `{:?}` mode, I think it is still more readable).

We could make it even smaller by deviating further from what the actual code looks like, e.g. via something like `Size(4 bytes)`. Not sure what people would think about that?

Cc ```@oli-obk```

…ession, r=notriddle

Fix jump to def regression

rust-lang#93803 introduced a regression in the "jump to def" feature. This fixes it.

Nice side-effect: it adds a new regression test. :)

I also used this opportunity to add documentation about this unstable feature in the rustdoc book.

cc `@cjgillot`
r? `@notriddle`

Fix an ICE on rust-lang#96738

In the block we don't know if the method actually exists thus `expect_local` panics.
Fixes rust-lang#96738

…c, r=oli-obk

diagnostics: port more diagnostics to derive + add support for `Vec` fields

- Port "unconstrained opaque type" diagnostic to using the derive.
- Allow `Vec` fields in diagnostic derive - enables support for diagnostics that have multiple primary spans, or have subdiagnostics repeated at multiple locations. `Vec<..>` fields in the diagnostic derive become loops in the generated code.
- Add `create_{err,warning}` - there wasn't a way to create a diagnostic from a struct and not emit it straight away.
- Port "explicit generic args w/ impl trait" diagnostic to using the derive.

r? ```@oli-obk```
cc ```@pvdrz```

…-take-2, r=petrochenkov

Remove closures on `expect_local` to apply `#[track_caller]`

Pointed out in rust-lang#96747 (comment)
Didn't change `expect_non_local` as I'm not sure if it's also the case.
r? `@petrochenkov`

…nstable_book, r=ehuss

Fix an incorrect link in The Unstable Book

https://github.com/rust-lang/rust/blob/master/src/librustc_session/lint/builtin.rs returns page not found.

The following is the background of the move.
First rust-lang#74862 moves from src/librustc_session/lint/builtin.rs to compiler/rustc_session/src/lint/builtin.rs.
Then rust-lang@23018a5 moves from compiler/rustc_session/src/lint/builtin.rs to compiler/rustc_lint_defs/src/builtin.rs.

So, the current correct link is https://github.com/rust-lang/rust/blob/master/compiler/rustc_lint_defs/src/builtin.rs.

This PR fixes a broken link on the following page:
https://doc.rust-lang.org/beta/unstable-book/language-features/plugin.html

…er-errors

Link to correct issue in issue-95034 known-bug

fix a typo is issue number: 94034 -> 95034