Fixes rust-lang#87994

It was accidentally changed to use `opts()` in rust-lang#86451.

I also renamed `opts()` to `main_body_opts()` to make this kind of
accidental change less likely.

This fixes odd renderings when these features are used in the first
paragraph of documentation for an item. This is an extension of rust-lang#87270.

Previous version wrongly used `but` while the two parts of the sentence are not contradicting but completing with each other.

this also renders them as `_`, which rustdoc previously did not.

Note that this incorrectly suggests a shared borrow,
but at least we know it's happening.

These were deleted in https://reviews.llvm.org/D108614, and in C++ I
definitely see the argument for their removal. I didn't try and
propagate the changes up into higher layers of rustc in this change
because my initial goal was to get rustc working against LLVM HEAD
promptly, but I'm happy to follow up with some refactoring to make the
API on the Rust side match the LLVM API more directly (though the way
the enum works in Rust makes the API less scary IMO).

r? @nagisa cc @nikic

Otherwise we're kind of reimplementing the inverse of the well-named
methods, and that's not a direction we want to go.

Turns out we can also use Attribute::get*() methods here, and avoid the
AttrBuilder and an extra helper method here.

See rust-lang#88545 for more details

This commit focuses on emitting clean errors for the following syntax
error:

```
Some(42).map(|a|
    dbg!(a);
    a
);
```

Previous implementation tried to recover after parsing the closure body
(the `dbg` expression) by replacing the next `;` with a `,`, which made
the next expression belong to the next function argument. As such, the
following errors were emitted (among others):
  - the semicolon token was not expected,
  - a is not in scope,
  - Option::map is supposed to take one argument, not two.

This commit allows us to gracefully handle this situation by adding
giving the parser the ability to remember when it has just parsed a
closure body inside a function call. When this happens, we can treat the
unexpected `;` specifically and try to parse as much statements as
possible in order to eat the whole block. When we can't parse statements
anymore, we generate a clean error indicating that the braces are
missing, and return an ExprKind::Err.

…e analysis

…r tuple struct fields.

…akis

Ignore derived Clone and Debug implementations during dead code analysis

This pull request fixes rust-lang#84647. Derived implementations of `Clone` and `Debug` always trivially read all fields, so "field is never read" dead code warnings are never triggered. Arguably, though, a user most likely will only be interested in whether _their_ code ever reads those fields, which is the behavior I have implemented here.

Note that implementations of `Clone` and `Debug` are only ignored if they are `#[derive(...)]`d; a custom `impl Clone/Debug for ...` will still be analyzed normally (i.e. if a custom `Clone` implementation uses all fields of the struct, this will continue to suppress dead code warnings about unused fields); this seemed like the least intrusive change to me (although it would be easy to change — just drop the `&& [impl_]item.span.in_derive_expansion()` in the if conditions).

The only thing that I am slightly unsure about is that in rust-lang#84647, `@matklad` said
> Doesn't seem easy to fix though :(

However, it _was_ pretty straightforward to fix, so did I perhaps overlook something obvious? `@matklad,` could you weigh in on this?

…tolnay

Add proc_macro::Span::{before, after}.

This adds `proc_macro::Span::before()` and `proc_macro::Span::after()` to get a zero width span at the start or end of the span.

These are equivalent to rustc's `Span::shrink_to_lo()` and `Span::shrink_to_hi()` but with a less cryptic name. They are useful when generating diagnostlics like "missing \<thing\> after \<thing\>".

E.g.

```rust
syn::Error::new(ident.span().after(), "missing `:` after field name").into_compile_error()
```

Fix stray notes when the source code is not available

Fixes rust-lang#87060. To reproduce it with a local build of rustc, you have to copy the compiler (e.g. `build/x86_64-unknown-linux-gnu/stage1/`) somewhere and then rename the compiler source directory (maybe there is a smarter way as well). Then, rustc won't find the standard library sources and report stray notes such as
```
note: deref defined here
```
with no location for "here". Another example I've found is this:
```rust
use std::ops::Add;

fn foo<T: Add<Output=()>>(x: T) {
    x + x;
}

fn main() {}
```
```
error[E0382]: use of moved value: `x`
  --> binop.rs:4:9
   |
3  | fn foo<T: Add<Output=()>>(x: T) {
   |                           - move occurs because `x` has type `T`, which does not implement the `Copy` trait
4  |     x + x;
   |     ----^
   |     |   |
   |     |   value used here after move
   |     `x` moved due to usage in operator
   |
note: calling this operator moves the left-hand side
help: consider further restricting this bound
   |
3  | fn foo<T: Add<Output=()> + Copy>(x: T) {
   |                          ^^^^^^

error: aborting due to previous error
```
where, again, the note is supposed to point somewhere but doesn't. I have fixed this by checking whether the corresponding source code is actually available before emitting the note.

Emit suggestion when passing byte literal to format macro

Closes rust-lang#86865

…races, r=estebank

Emit proper errors when on missing closure braces

This commit focuses on emitting clean errors for the following syntax
error:

```
Some(42).map(|a|
    dbg!(a);
    a
);
```

Previous implementation tried to recover after parsing the closure body
(the `dbg` expression) by replacing the next `;` with a `,`, which made
the next expression belong to the next function argument. As such, the
following errors were emitted (among others):
  - the semicolon token was not expected,
  - a is not in scope,
  - Option::map is supposed to take one argument, not two.

This commit allows us to gracefully handle this situation by adding
giving the parser the ability to remember when it has just parsed a
closure body inside a function call. When this happens, we can treat the
unexpected `;` specifically and try to parse as much statements as
possible in order to eat the whole block. When we can't parse statements
anymore, we generate a clean error indicating that the braces are
missing, and return an ExprKind::Err.

Closes rust-lang#88065.

r? `@estebank`

…erence-to-for-loop-iter, r=nagisa

fix(rustc): suggest `items` be borrowed in `for i in items[x..]`

Fixes rust-lang#87994

Fix issues with Markdown summary options

- Use `summary_opts()` for Markdown summaries
- Enable all main body Markdown options for summaries

…aumeGomez

rustdoc: Fix ICE with `doc(hidden)` on tuple variant fields

Fixes rust-lang#88600.

```rust
pub struct H;
pub struct S;

pub enum FooEnum {
    HiddenTupleItem(#[doc(hidden)] H),
    MultipleHidden(#[doc(hidden)] H, #[doc(hidden)] H),
    MixedHiddenFirst(#[doc(hidden)] H, S),
    MixedHiddenLast(S, #[doc(hidden)] H),
    HiddenStruct {
        #[doc(hidden)]
        h: H,
        s: S,
    },
}
```

Generates
![image](https://user-images.githubusercontent.com/1502855/132259152-382f9517-c2a0-41d8-acd0-64e5993931fc.png)

Tweak `write_fmt` doc.

Found this weird sentence while reading the docs.

…lds-count, r=Manishearth

Rustdoc coverage fields count

Follow-up of rust-lang#88688.

Instead of requiring enum tuple variant fields and tuple struct fields to be documented, we count them if they are documented, otherwise we don't include them in the count.

r? `@Manishearth`

RustWrapper: avoid deleted unclear attribute methods

These were deleted in https://reviews.llvm.org/D108614, and in C++ I
definitely see the argument for their removal. I didn't try and
propagate the changes up into higher layers of rustc in this change
because my initial goal was to get rustc working against LLVM HEAD
promptly, but I'm happy to follow up with some refactoring to make the
API on the Rust side match the LLVM API more directly (though the way
the enum works in Rust makes the API less scary IMO).

r? ``@nagisa`` cc ``@nikic``

…ks, r=nbdd0121

Fix table in docblocks

"Overwrite" of rust-lang#88702.

Instead of adding a z-index to the sidebar (which only hides the issue, doesn't fix it), I wrap `<table>` elements inside a `<div>` and limit all chidren of `.docblock` elements' width to prevent having the scrollbar on the whole doc block.

![Screenshot from 2021-09-08 15-11-24](https://user-images.githubusercontent.com/3050060/132515740-71796515-e74f-429f-ba98-2596bdbf781c.png)

Thanks `@nbdd0121` for `overflow-x: auto;`. ;)

r? `@notriddle`

…ements_grid_bug, r=GuillaumeGomez

Workaround blink/chromium grid layout limitation of 1000 rows

I made this in case we don't come up with a better solution in time.

See rust-lang#88545 for more details.

A rendered version of the standard library is hosted here:
https://data.estada.ch/rustdoc-nightly_497ee321af_2021-09-09/core/arch/arm/index.html

r? `@GuillaumeGomez` `@jsha`

…plett

Fix typo in docs for iterators

Fix typo `option` -> `options`.