Remove a no-longer-true assert
Fixes https://github.com/rust-lang/rust/issues/129009
The assert was simply no longer true. I thought my test suite was thorough but I had not noticed these `let`-specific diagnostics codepaths.
r? `@compiler-errors`
Add windows-targets crate to std's sysroot
With this PR, when backtrace is used as a crate from crates.io it will (once updated) use the real [windows-targets](https://crates.io/crates/windows-targets) crate. But when used from std it'll use std's replacement version.
This allows sharing our customized `windows_tagets::link!` macro between std proper and the backtrace crate when used as part of std, ensuring a consistent linking story. This will be especially important once we move to using [`raw-dylib`](https://doc.rust-lang.org/reference/items/external-blocks.html#dylib-versus-raw-dylib) by default.
Migrate `remap-path-prefix-dwarf` `run-make` test to rmake
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
Possibly my proudest branch name yet.
try-job: aarch64-apple
try-job: armhf-gnu
try-job: test-various
try-job: x86_64-gnu-llvm-18
Shrink `TyKind::FnPtr`.
By splitting the `FnSig` within `TyKind::FnPtr` into `FnSigTys` and `FnHeader`, which can be packed more efficiently. This reduces the size of the hot `TyKind` type from 32 bytes to 24 bytes on 64-bit platforms. This reduces peak memory usage by a few percent on some benchmarks. It also reduces cache misses and page faults similarly, though this doesn't translate to clear cycles or wall-time improvements on CI.
r? `@compiler-errors`
Greatly speed up doctests by compiling compatible doctests in one file
Fixes#75341.
Take 2 at https://github.com/rust-lang/rust/pull/123974. It should now be much simpler to review since it's based on https://github.com/rust-lang/rust/pull/125798.
I split the changes as much as possible to make it as easy as possible to review (even though it's a huge lot of code changes...).
The following tests are not included into the combined doctests:
* `compile_fail`
* If there are crate attributes (`deny`/`allow`/`warn` are ok)
* have invalid AST
* `test_harness`
* no capture
* `--show-output` (because the output is nicer without the extra code surrounding it)
Everything else is merged into one file. If this one file fails to compile, we go back to the current strategy: compile each doctest separately.
Because of the `edition` codeblock attribute, I couldn't make them all into one file directly so I grouped them by edition, but it should be pretty anecdotic.
In case the users want a specific doctest to be opted-out from this doctest merge, I added the `standalone` codeblock attribute:
```rust
/// ```rust,standalone
/// // This doctest will be run in its own process!
/// ```
```
Now the interesting part, I ran it on a few crates and here are the results (with `cargo test --doc` to only include doctests):
| crate | nb doctests | before this PR | with this PR |
| - | - | - | - |
| sysinfo | 227 | 4.6s | 1.11s |
| geos | 157 | 3.95s | 0.45s |
| core | 4604 | 54.08s | 13.5s (merged: 0.9s, standalone: 12.6s) |
| std | 1147 | 12s | 3.56s (merged: 2.1s, standalone: 1.46s) |
r? `@camelid`
try-job: x86_64-msvc
try-job: aarch64-apple
