When encountering

```rust
fn f<T>(a: T, b: T) -> std::cmp::Ordering {
    a.cmp(&b) //~ ERROR E0599
}
```

output

```
error[E0599]: no method named `cmp` found for type parameter `T` in the current scope
  --> $DIR/method-on-unbounded-type-param.rs:2:7
   |
LL | fn f<T>(a: T, b: T) -> std::cmp::Ordering {
   |      - method `cmp` not found for this type parameter
LL |     a.cmp(&b)
   |       ^^^ method cannot be called on `T` due to unsatisfied trait bounds
   |
   = help: items from traits can only be used if the type parameter is bounded by the trait
help: the following traits define an item `cmp`, perhaps you need to restrict type parameter `T` with one of them:
   |
LL | fn f<T: Ord>(a: T, b: T) -> std::cmp::Ordering {
   |       +++++
LL | fn f<T: Iterator>(a: T, b: T) -> std::cmp::Ordering {
   |       ++++++++++
```

Fix rust-lang#120186.

When a method not found on a type parameter could have been provided by any
of multiple traits, suggest each trait individually, instead of a single
suggestion to restrict the type parameter with *all* of them.

Before:

```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
  --> $DIR/method-on-unbounded-type-param.rs:5:10
   |
LL |     (&a).cmp(&b)
   |          ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
   |
   = note: the following trait bounds were not satisfied:
           `T: Ord`
           which is required by `&T: Ord`
           `&T: Iterator`
           which is required by `&mut &T: Iterator`
           `T: Iterator`
           which is required by `&mut T: Iterator`
help: consider restricting the type parameters to satisfy the trait bounds
   |
LL | fn g<T>(a: T, b: T) -> std::cmp::Ordering where T: Iterator, T: Ord {
   |                                           +++++++++++++++++++++++++
```

After:

```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
  --> $DIR/method-on-unbounded-type-param.rs:5:10
   |
LL |     (&a).cmp(&b)
   |          ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
   |
   = note: the following trait bounds were not satisfied:
           `T: Ord`
           which is required by `&T: Ord`
           `&T: Iterator`
           which is required by `&mut &T: Iterator`
           `T: Iterator`
           which is required by `&mut T: Iterator`
   = help: items from traits can only be used if the type parameter is bounded by the trait
help: the following traits define an item `cmp`, perhaps you need to restrict type parameter `T` with one of them:
   |
LL | fn g<T: Ord>(a: T, b: T) -> std::cmp::Ordering {
   |       +++++
LL | fn g<T: Iterator>(a: T, b: T) -> std::cmp::Ordering {
   |       ++++++++++
```

Fix rust-lang#108428.

Disable packed/unpacked options for riscv linux/android.
Other riscv targets already only have the off option.

The packed/unpacked options might be supported in the future.
See upstream issue for more details:
llvm/llvm-project#56642

Fixes rust-lang#110224

To send a diagnostic from a codegen thread to the main thread,
`SharedEmitter` currently converts the `rustc_errors::Diagnostic` into a
one or more `rustc_codegen_ssa::Diagnostic`s, sends them, and then
`SharedEmitterMain` reconstructs them at the other end into a
`rustc_errors::Diagnostic`. This is a lossy operation, because of
differences between the two `Diagnostic` types.

Instead we can just clone the `rustc_errors::Diagnostic` and send it
directly. Maybe in the past `rustc_errors::Diagnostic` wasn't `Send`?
But it works now. Much simpler and nicer.

It's now always paired with a `SharedEmitterMessage::Diagnostic`, so the
two message kinds can be combined.

All the other `emit`/`emit_diagnostic` methods were recently made
consuming (e.g. rust-lang#119606), but this one wasn't. But it makes sense to.

Much of this is straightforward, and lots of `clone` calls are avoided.
There are a couple of tricky bits.
- `Emitter::primary_span_formatted` no longer takes a `Diagnostic` and
  returns a pair. Instead it takes the two fields from `Diagnostic` that
  it used (`span` and `suggestions`) as `&mut`, and modifies them. This
  is necessary to avoid the cloning of `diag.children` in two emitters.
- `from_errors_diagnostic` is rearranged so various uses of `diag` occur
  before the consuming `emit_diagnostic` call.

…peof` expression

…as already tainted

Account for non-overlapping unmet trait bounds in suggestion

When a method not found on a type parameter could have been provided by any
of multiple traits, suggest each trait individually, instead of a single
suggestion to restrict the type parameter with *all* of them.

Before:

```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
  --> $DIR/method-on-unbounded-type-param.rs:5:10
   |
LL |     (&a).cmp(&b)
   |          ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
   |
   = note: the following trait bounds were not satisfied:
           `T: Ord`
           which is required by `&T: Ord`
           `&T: Iterator`
           which is required by `&mut &T: Iterator`
           `T: Iterator`
           which is required by `&mut T: Iterator`
help: consider restricting the type parameters to satisfy the trait bounds
   |
LL | fn g<T>(a: T, b: T) -> std::cmp::Ordering where T: Iterator, T: Ord {
   |                                           +++++++++++++++++++++++++
```

After:

```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
  --> $DIR/method-on-unbounded-type-param.rs:5:10
   |
LL |     (&a).cmp(&b)
   |          ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
   |
   = note: the following trait bounds were not satisfied:
           `T: Ord`
           which is required by `&T: Ord`
           `&T: Iterator`
           which is required by `&mut &T: Iterator`
           `T: Iterator`
           which is required by `&mut T: Iterator`
   = help: items from traits can only be used if the type parameter is bounded by the trait
help: the following traits define an item `cmp`, perhaps you need to restrict type parameter `T` with one of them:
   |
LL | fn g<T: Ord>(a: T, b: T) -> std::cmp::Ordering {
   |       +++++
LL | fn g<T: Iterator>(a: T, b: T) -> std::cmp::Ordering {
   |       ++++++++++
```

Fix rust-lang#108428.

Follow up to rust-lang#120396, only last commit is relevant.

…piler-errors

riscv only supports split_debuginfo=off for now

Disable packed/unpacked options for riscv linux/android. Other riscv targets already only have the off option.

The packed/unpacked options might be supported in the future. See upstream issue for more details:
llvm/llvm-project#56642

Fixes rust-lang#110224

…ructors, r=dtolnay,oli-obk

Make `NonZero` constructors generic.

This makes `NonZero` constructors generic, so that `NonZero::new` can be used without turbofish syntax.

Tracking issue: rust-lang#120257

~~I cannot figure out how to make this work with `const` traits. Not sure if I'm using it wrong or whether there's a bug:~~

```rust
101 |         if n == T::ZERO {
    |            ^^^^^^^^^^^^ expected `host`, found `true`
    |
    = note: expected constant `host`
               found constant `true`
```

r? `@dtolnay`

…ochenkov

Switch OwnedStore handle count to AtomicU32

This is already panics if overflowing a u32, so let's use the smaller int size to save a tiny bit of memory.

Continue to borrowck even if there were previous errors

but only from the perspective of the whole compiler. Individual items should not get borrowcked if their MIR is tainted by errors.

r? `@estebank` `@nnethercote`

…handling, r=estebank

Simplify codegen diagnostic handling

Some nice improvements. Details in the individual commit logs.

r? `@estebank`

…RalfJung

miri: normalize struct tail in ABI compat check

fixes rust-lang/miri#3282
extracted from rust-lang#120354, see rust-lang#120354 (comment) for context

r? `@RalfJung`

Remove unused args from functions

`#[instrument]` suppresses the unused arguments from a function, *and* suppresses unused methods too! This PR removes things which are only used via `#[instrument]` calls, and fixes some other errors (privacy?) that I will comment inline.

It's possible that some of these arguments were being passed in for the purposes of being instrumented, but I am unconvinced by most of them.

fix rust-lang#120603 by adding a check in default_read_buf

Fixes rust-lang#120603 by checking the returned read n is in-bounds of the cursor.

Interestingly, I noticed that `BorrowedBuf` side-steps this issue by using checked accesses. Maybe this can be switched to unchecked to mirror what BufReader does https://github.com/rust-lang/rust/blob/bf3c6c5bed498f41ad815641319a1ad9bcecb8e8/library/core/src/io/borrowed_buf.rs#L95