…r=Amanieu

improve error message when `global_asm!` uses `asm!` options

specifically, what was

    error: expected one of `)`, `att_syntax`, or `raw`, found `preserves_flags`
      --> $DIR/bad-options.rs:45:25
       |
    LL | global_asm!("", options(preserves_flags));
       |                         ^^^^^^^^^^^^^^^ expected one of `)`, `att_syntax`, or `raw`

is now

    error: the `preserves_flags` option cannot be used with `global_asm!`
      --> $DIR/bad-options.rs:45:25
       |
    LL | global_asm!("", options(preserves_flags));
       |                         ^^^^^^^^^^^^^^^ the `preserves_flags` option is not meaningful for global-scoped inline assembly

mirroring the phrasing of the [reference](https://doc.rust-lang.org/reference/inline-assembly.html#options).

This is also a bit of a refactor for a future `naked_asm!` macro (for use in `#[naked]` functions). Currently this sort of error can come up when switching from inline to global asm, or when a user just isn't that experienced with assembly. With  `naked_asm!` added to the mix hitting this error is more likely.

…iaskrgr

Rollup of 3 pull requests

Successful merges:

 - rust-lang#128006 (Make `missing_fragment_specifier` an error in edition 2024)
 - rust-lang#128207 (improve error message when `global_asm!` uses `asm!` options)
 - rust-lang#128266 (update `rust.channel` default value documentation)

r? `@ghost`
`@rustbot` modify labels: rollup

Rollup of 8 pull requests

Successful merges:

 - rust-lang#125897 (from_ref, from_mut: clarify documentation)
 - rust-lang#128207 (improve error message when `global_asm!` uses `asm!` options)
 - rust-lang#128241 (Remove logic to suggest clone of function output)
 - rust-lang#128259 ([illumos/solaris] set MSG_NOSIGNAL while writing to sockets)
 - rust-lang#128262 (Delete `SimplifyArmIdentity` and `SimplifyBranchSame` tests)
 - rust-lang#128266 (update `rust.channel` default value documentation)
 - rust-lang#128267 (Add rustdoc GUI test to check title with and without search)
 - rust-lang#128271 (Disable jump threading of float equality)

r? `@ghost`
`@rustbot` modify labels: rollup

Rollup merge of rust-lang#128207 - folkertdev:asm-parser-generalize, r=Amanieu

improve error message when `global_asm!` uses `asm!` options

specifically, what was

    error: expected one of `)`, `att_syntax`, or `raw`, found `preserves_flags`
      --> $DIR/bad-options.rs:45:25
       |
    LL | global_asm!("", options(preserves_flags));
       |                         ^^^^^^^^^^^^^^^ expected one of `)`, `att_syntax`, or `raw`

is now

    error: the `preserves_flags` option cannot be used with `global_asm!`
      --> $DIR/bad-options.rs:45:25
       |
    LL | global_asm!("", options(preserves_flags));
       |                         ^^^^^^^^^^^^^^^ the `preserves_flags` option is not meaningful for global-scoped inline assembly

mirroring the phrasing of the [reference](https://doc.rust-lang.org/reference/inline-assembly.html#options).

This is also a bit of a refactor for a future `naked_asm!` macro (for use in `#[naked]` functions). Currently this sort of error can come up when switching from inline to global asm, or when a user just isn't that experienced with assembly. With  `naked_asm!` added to the mix hitting this error is more likely.

…operand, r=Amanieu

improve error message when `global_asm!` uses `asm!` operands

follow-up to rust-lang#128207

what was

```
error: expected expression, found keyword `in`
 --> src/lib.rs:1:31
  |
1 | core::arch::global_asm!("{}", in(reg));
  |                               ^^ expected expression
```

becomes

```
error: the `in` operand cannot be used with `global_asm!`
  --> $DIR/parse-error.rs:150:19
   |
LL | global_asm!("{}", in(reg));
   |                   ^^ the `in` operand is not meaningful for global-scoped inline assembly, remove it
```

the span of the error is just the keyword, which means that we can't create a machine-applicable suggestion here. The alternative would be to attempt to parse the full operand, but then if there are syntax errors in the operand those would  be presented to the user, even though the parser already knows that the output won't be valid. Also that would require more complexity in the parser.

So I think this is a nice improvement at very low cost.

…operand, r=Amanieu

improve error message when `global_asm!` uses `asm!` operands

follow-up to rust-lang#128207

what was

```
error: expected expression, found keyword `in`
 --> src/lib.rs:1:31
  |
1 | core::arch::global_asm!("{}", in(reg));
  |                               ^^ expected expression
```

becomes

```
error: the `in` operand cannot be used with `global_asm!`
  --> $DIR/parse-error.rs:150:19
   |
LL | global_asm!("{}", in(reg));
   |                   ^^ the `in` operand is not meaningful for global-scoped inline assembly, remove it
```

the span of the error is just the keyword, which means that we can't create a machine-applicable suggestion here. The alternative would be to attempt to parse the full operand, but then if there are syntax errors in the operand those would  be presented to the user, even though the parser already knows that the output won't be valid. Also that would require more complexity in the parser.

So I think this is a nice improvement at very low cost.

Rollup merge of rust-lang#128305 - folkertdev:asm-parser-unsupported-operand, r=Amanieu

improve error message when `global_asm!` uses `asm!` operands

follow-up to rust-lang#128207

what was

```
error: expected expression, found keyword `in`
 --> src/lib.rs:1:31
  |
1 | core::arch::global_asm!("{}", in(reg));
  |                               ^^ expected expression
```

becomes

```
error: the `in` operand cannot be used with `global_asm!`
  --> $DIR/parse-error.rs:150:19
   |
LL | global_asm!("{}", in(reg));
   |                   ^^ the `in` operand is not meaningful for global-scoped inline assembly, remove it
```

the span of the error is just the keyword, which means that we can't create a machine-applicable suggestion here. The alternative would be to attempt to parse the full operand, but then if there are syntax errors in the operand those would  be presented to the user, even though the parser already knows that the output won't be valid. Also that would require more complexity in the parser.

So I think this is a nice improvement at very low cost.

…r=Amanieu

improve error message when `global_asm!` uses `asm!` operands

follow-up to rust-lang/rust#128207

what was

```
error: expected expression, found keyword `in`
 --> src/lib.rs:1:31
  |
1 | core::arch::global_asm!("{}", in(reg));
  |                               ^^ expected expression
```

becomes

```
error: the `in` operand cannot be used with `global_asm!`
  --> $DIR/parse-error.rs:150:19
   |
LL | global_asm!("{}", in(reg));
   |                   ^^ the `in` operand is not meaningful for global-scoped inline assembly, remove it
```

the span of the error is just the keyword, which means that we can't create a machine-applicable suggestion here. The alternative would be to attempt to parse the full operand, but then if there are syntax errors in the operand those would  be presented to the user, even though the parser already knows that the output won't be valid. Also that would require more complexity in the parser.

So I think this is a nice improvement at very low cost.