rustdoc: Remove Derived Implementations title
As far as I know whether a trait was derived or not does not change the
public API so there is no need to include this information in the docs.
This title currently just adds an extra divide in the list of trait
implementations which I don't think needs to be there.
- src links/redirects to extern fn from another crate had an extra '/'.
- src links to `pub use` of a crate module had an extra '/'.
- src links to renamed reexports from another crate used the new name
for the link but should use the original name.
rustdoc: Fix redirect pages for renamed reexports
We need to use the name of the target not the name of the current item
when creating the link.
An example in `std` is [`std::sys::ext`](https://doc.rust-lang.org/nightly/std/sys/ext/index.html).
Fix invalid inlining
r? @steveklabnik
So to put a context. @nox found an issue on the generated doc:

So as you can see, the two variants are on the same where they shouldn't. I found out that the issue is also on structs:

And so such is the result of the PR:


rustdoc: Don't generate empty files for stripped items
We need to traverse stripped modules to generate redirect pages, but we shouldn't generate
anything else for them.
This now renders the file contents to a Vec before writing it to a file in one go. I think
that's probably a better strategy anyway.
Fixes: #34025
Refactor away the prelude injection fold
Instead, just inject `#[prelude_import] use [core|std]::prelude::v1::*;` at the crate root while injecting `extern crate [core|std];` and process `#[no_implicit_prelude]` attributes in `resolve`.
r? @nrc
As far as I know whether a trait was derived or not does not change the
public API so there is no need to include this information in the docs.
This title currently just adds an extra divide in the list of trait
implementations which I don't think needs to be there.
We need to traverse stripped modules to generate redirect pages, but we shouldn't generate
anything else for them.
This now renders the file contents to a Vec before writing it to a file in one go. I think
that's probably a better strategy anyway.
rustdoc: Add doc snippets for trait impls, with a read more link
The read more link only appears if the documentation is more than one line long.

It currently does not appear on non-defaulted methods, since you can document them directly. I could make it so that default documentation gets forwarded if regular docs don't exist.
Fixes#33672
r? @alexcrichton
cc @steveklabnik
rustdoc: add "src" links to individual impls
Since these impls can be scattered around quite a bit, it is nice to be able to jump to the location where individual methods and trait impls are defined.
NOTE: this needs an update to the CSS, which I'd like to leave for whoever is the "rustdoc frontend champion". The new [src] links are currently too large and bold. Also, the interaction with the "since version X" annotations is not good.
Fixes: #30416
Since these impls can be scattered around quite a bit, it is nice
to be able to jump to the location where individual methods and
trait impls are defined.
Fixes: #30416
Especially in cases like the one in the test file, this can blow
up the docs big time if string constants in the code contain HTML.
But also other constants can contain special chars (e.g. `&` as an
operator in constant expressions).
rustdoc: Cleanup ABI rendering
Use a common method for rendering `extern "<abi>"`.
This now consistently shows `extern fn` rather than `extern "C" fn`.
rustdoc: Handle concurrent mkdir requests
It's likely that `rustdoc` as a tool is run concurrently in the same output
(e.g. documenting multiple crates as Cargo does), in which case it needs to
handle concurrent calls to `fs::create_dir`.
It's likely that `rustdoc` as a tool is run concurrently in the same output
(e.g. documenting multiple crates as Cargo does), in which case it needs to
handle concurrent calls to `fs::create_dir`.
Due to inlining it is possible to visit the same module multiple times
during `<Cache as DocFolder>::fold_crate`, so we keep track of the
modules we've already visited.
rustdoc: refine cross-crate impl inlining
This changes the current rule that impls within `doc(hidden)` modules aren't inlined, to only inlining impls where the implemented trait and type are reachable in documentation.
fixes#14586fixes#31948
.. and also applies the reachability checking to cross-crate links.
fixes#28480
r? @alexcrichton
This changes the current rule that impls within `doc(hidden)` modules
aren't inlined, to only inlining impls where the implemented
trait and type are reachable in documentation.