Fixes rust-lang#121593

Given `'hello world'` and `'1 str', provide a structured suggestion for a valid string literal:

```
error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-3.rs:2:26
   |
LL |     println!('hello world');
   |                          ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("hello world");
   |              ~           ~
```
```
error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-1.rs:2:20
   |
LL |     println!('1 + 1');
   |                    ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("1 + 1");
   |              ~     ~
```

Fix rust-lang#119685.

… in 2021 edition

This target is a Tier 3 target so it's not tested on CI, and it's broken
since last used so this commit fixes a small unwind-related issue that
cropped up in the meantime.

Current `transform_ty` attempts to avoid cycles when normalizing
`#[repr(transparent)]` types to their interior, but runs afoul of this
pattern used in `self_cell`:

```
struct X<T> {
  x: u8,
  p: PhantomData<T>,
}

 #[repr(transparent)]
struct Y(X<Y>);
```

When attempting to normalize Y, it will still cycle indefinitely. By
using a types-visited list, this will instead get expanded exactly
one layer deep to X<Y>, and then stop, not attempting to normalize `Y`
any further.

Fixes rust-lang#99945

…01852

Fixes rust-lang#101852

…E: IndexMap: key not found

Fixes rust-lang#104779

…trait system" rust-lang#105047

Fixes rust-lang#105047

Fixes rust-lang#106423

Fixes rust-lang#106444

Fixes rust-lang#106874

Fixes rust-lang#107228

…ethods

We already use `Instance` at declaration sites when available to glean
additional information about possible abstractions of the type in use.
This does the same when possible at callsites as well.

The primary purpose of this change is to allow CFI to alter how it
generates type information for indirect calls through `Virtual`
instances.

Additional trait bounds beyond the principal trait and its implications
are not possible in the vtable. This means that if a receiver is
`&dyn Foo + Send`, the function will only be expecting `&dyn Foo`.

This strips those auto traits off before CFI encoding.

…spans.

This makes `-Zprint-type-sizes`'s output easier to read, because the
name of an `async fn` is more immediately recognizable than its span.

I also deleted the comment "FIXME(eddyb) should use `def_span`." because
it appears to have already been fixed by commit 67727aa.

Rather than `.into_iter().rev().find_position(...)`, this case can
simply call `.iter().rposition(...)`.

regression test for rust-lang#103626

I don't know what a descriptive filename for this would be.

Fixes rust-lang#103626

…mease

Mention Register Size in `#[warn(asm_sub_register)]`

Fixes rust-lang#121593

Displays the register size information obtained from `suggest_modifier()` and `default_modifier()`.

Handle str literals written with `'` lexed as lifetime

Given `'hello world'` and `'1 str', provide a structured suggestion for a valid string literal:

```
error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-3.rs:2:26
   |
LL |     println!('hello world');
   |                          ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("hello world");
   |              ~           ~
```
```
error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-1.rs:2:20
   |
LL |     println!('1 + 1');
   |                    ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("1 + 1");
   |              ~     ~
```

Fix rust-lang#119685.

transmute: caution against int2ptr transmutation

This came up in rust-lang#121282.
Cc `````@saethlin````` `````@scottmcm`````

Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.

…=Nilstrieb

Rework rmake support library API

### Take 1: Strongly-typed API

Context: rust-lang#122448 (comment)

> My 2 cents: from my experience with writing similar "test DSLs", I would suggest to create these helpers as soon as possible in the process (basically the first time someone needs them, not only after N similar usages), and basically treat any imperative code in these high-level tests as a maintenance burden, basically making them as declarative as possible. Otherwise it might be a bit annoying to keep refactoring the tests later once such helpers are available.
>
> I would even discourage the arg method and create explicit methods for setting things like unpretty, the output file etc., but this might be more controversial, as it will make the invoked command-line arguments more opaque.

cc ``@Kobzol`` for the testing DSL suggestion.

Example:

```rs
let output = Rustc::new()
    .input_file("main.rs")
    .emit(&[EmitKind::Metadata])
    .extern_("stable", &stable_path)
    .output();
```

### Take 2: xshell-based macro API

Example:

```rs
let sh = Shell::new()?;
let stable_path = stable_path.to_string_lossy();
let output = cmd!(sh, "rustc main.rs --emit=metadata --extern stable={stable_path}").output()?;
```

### Take 3: Weakly-typed API with a few helper methods

```rs
let output = Rustc::new()
    .input("main.rs")
    .emit("metadata")
    .extern_("stable", &stable_path)
    .output();
```

…=Mark-Simulacrum

Fix compile of wasm64-unknown-unknown target

This target is a Tier 3 target so it's not tested on CI, and it's broken since last used so this commit fixes a small unwind-related issue that cropped up in the meantime.

…, r=workingjubilee

CFI: Support self_cell-like recursion

Current `transform_ty` attempts to avoid cycles when normalizing `#[repr(transparent)]` types to their interior, but runs afoul of this pattern used in `self_cell`:

```
struct X<T> {
  x: u8,
  p: PhantomData<T>,
}

 #[repr(transparent)]
struct Y(X<Y>);
```

When attempting to normalize Y, it will still cycle indefinitely. By using a types-visited list, this will instead get expanded exactly one layer deep to X<Y>, and then stop, not attempting to normalize `Y` any further.

This PR was split off from rust-lang#121962 as part of fixing the larger vtable compatibility issues.

r? ````@workingjubilee````

…ngjubilee

CFI: Strip auto traits off Virtual calls

We already use `Instance` at declaration sites when available to glean additional information about possible abstractions of the type in use. This does the same when possible at callsites as well.

The primary purpose of this change is to allow CFI to alter how it generates type information for indirect calls through `Virtual` instances.

This is needed for the "separate machinery" version of my approach to the vtable issues (rust-lang#122573), because we need to respond differently to a `Virtual` call to the same type as a non-virtual call, specifically [stripping auto traits off the receiver's `Self`](rust-lang@54b15b0) because there isn't a separate vtable for `Foo` vs `Foo + Send`.

This would also make a more general underlying mechanism that could be used by rcvalle's [proposed drop detection / encoding](rust-lang@edcd1e2) if we end up using his approach, as we could condition out on the `def_id` in the CFI code rather than requiring the generating code to explicitly note whether it was calling drop.

…r=lcnr

Uniquify `ReError` on input mode in canonicalizer

See test descr

Fixes rust-lang#122861

r? lcnr

…-errors

In `pretty_print_type()`, print `async fn` futures' paths instead of spans.

This makes `-Zprint-type-sizes`'s output easier to read, because the name of an `async fn` is more immediately recognizable than its span. This change will also synergize with my other `-Zprint-type-sizes` PR rust-lang#122922 which prints the type of child futures being awaited.

I also deleted the comment "FIXME(eddyb) should use `def_span`." because it appears to have already been fixed by commit 67727aa.

Add test in higher ranked subtype

I'm a beginner in this repository, and there are some things I'm not sure about:

- Is it okay that there is a warning:
```
rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [?1t, '^0.Named(DefId(0:15 ~ structually_relate_aliases[de75]::{impl#1}::'a), "'a")], def_id: DefId(0:5 ~ structually_relate_aliases[de75]::ToUnit::Unit) }
```
- Is it okay that there are two duplicate errors in the same line?
- Did I put the test in the right place?

Any suggestions would be appreciated.

Fixes rust-lang#121649

…xxxx, r=fmease

add a couple more ice tests

Fixes rust-lang#104779
Fixes rust-lang#106423
Fixes rust-lang#106444
Fixes rust-lang#101852
Fixes rust-lang#106874
Fixes rust-lang#105047
Fixes rust-lang#107228
Fixes rust-lang#99945

core/panicking: fix outdated comment

Looks like this function got renamed/changed at some point and the comment did not get updated.

r? ```@m-ou-se```

…hewjasper

Simplify an iterator search in borrowck diag

Rather than `.into_iter().rev().find_position(...)`, this case can
simply call `.iter().rposition(...)`.