Add const generics to infer (and transitive dependencies)
Split out from #53645. This work is a collaborative effort with @yodaldevoid.
There are a number of stubs. These are mainly to ensure we don't overlook them when completing the implementation, but are not necessary for the initial implementation. We plan to address these in follow up PRs.
r? @eddyb / @nikomatsakis
Ensure that drop order of `async fn` matches `fn` and that users cannot refer to generated arguments.
Fixes#60236 and fixes#60438.
This PR modifies the lowering of `async fn` arguments so that the
drop order matches the equivalent `fn`.
Previously, async function arguments were lowered as shown below:
async fn foo(<pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
After this PR, async function arguments will be lowered as:
async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
async move {
let __arg2 = __arg2;
let <pattern> = __arg2;
let __arg1 = __arg1;
let <pattern> = __arg1;
let __arg0 = __arg0;
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
If `<pattern>` is a simple ident, then it is lowered to a single
`let <pattern> = <pattern>;` statement as an optimization.
This PR also stops users from referring to the generated `__argN`
identifiers.
r? @nikomatsakis
Added an explanation for the E0704 error.
# Description
Adds an explanation on the E0704 error. I tried to stick as closely to the message that the compiler generates. It's the first time I am fixing error messages here, so if there is something I did wrong or should improve, please let me know.
closes#55398
Rollup of 7 pull requests
Successful merges:
- #60287 (Use references for variances_of)
- #60327 (Search for incompatible universes in borrow errors)
- #60330 (Suggest using an inclusive range instead of an exclusive range when the endpoint overflows by 1)
- #60366 (build-gcc: Create missing cc symlink)
- #60369 (Support ZSTs in DispatchFromDyn)
- #60404 (Implement `BorrowMut<str>` for `String`)
- #60417 (Rename hir::ExprKind::Use to ::DropTemps and improve docs.)
Failed merges:
r? @ghost
This commit gensyms the generated ident for replacement arguments so
that users cannot refer to them. It also ensures that levenshtein
distance suggestions do not suggest gensymed identifiers.
This commit modifies the lowering of `async fn` arguments so that the
drop order matches the equivalent `fn`.
Previously, async function arguments were lowered as shown below:
async fn foo(<pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
After this PR, async function arguments will be lowered as:
async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
async move {
let __arg2 = __arg2;
let <pattern> = __arg2;
let __arg1 = __arg1;
let <pattern> = __arg1;
let __arg0 = __arg0;
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
If `<pattern>` is a simple ident, then it is lowered to a single
`let <pattern> = <pattern>;` statement as an optimization.
rustdoc: remove def_ctor hack.
~~No longer necessary since we have `describe_def`.~~
Turns out `def_ctor` was used in conjunction with abusing `tcx.type_of(def_id)` working on both type definitions and `impl`s (specifically, of builtin types), but also reimplementing a lot of the logic that `Clean` already provides on `Ty` / `ty::TraitRef`.
The first commit now does the minimal refactor to keep it working, while the second commit contains the rest of the refactor I started (parts of which I'm not sure we need to keep).
Support ZSTs in DispatchFromDyn
Allows to use ZSTs with 1 byte alignment in `DispatchFromDyn` implementation. This is required for `Box<T, A: Alloc>`
cc #58457
Search for incompatible universes in borrow errors
If we have a borrow that has to live for `'static` we need to check for
any regions in incompatible universes when trying to find the cause.
closes#60274
PGO: Add a run-make test that makes sure that PGO profiling data is used by the compiler during optimizations.
From the tests comment section:
```
# This test makes sure that PGO profiling data leads to cold functions being
# marked as `cold` and hot functions with `inlinehint`.
# The test program contains an `if` were actual execution only ever takes the
# `else` branch. Accordingly, we expect the function that is never called to
# be marked as cold.
```
r? @alexcrichton
This commit separates metadata encoding (`tcx.encode_metadata`) from the
creation of the metadata module (which is now handled by
`write_compressed_metadata`, formerly `write_metadata`).
The metadata encoding now occurs slightly earlier in the pipeline, at
the very start of code generation within `start_codegen`.
Metadata *writing* still occurs near the end of compilation; that will
be moved forward in subsequent commits.
In JSON output, emit a directive after metadata is generated.
To implement pipelining, Cargo needs to know when metadata generation is
finished. This is done via a new JSON "directive".
Unfortunately, metadata file writing currently occurs very late during
compilation, so pipelining won't produce a speed-up. Moving metadata
file writing earlier will be a follow-up.
r? @alexcrichton
To implement pipelining, Cargo needs to know when metadata generation is
finished. This commit adds code to do that. Unfortunately, metadata file
writing currently occurs very late during compilation, so pipelining
won't produce a speed-up. Moving metadata file writing earlier will be a
follow-up.
The change involves splitting the existing `Emitter::emit` method in
two: `Emitter::emit_diagnostic` and `Emitter::emit_directive`.
The JSON directives look like this:
```
{"directive":"metadata file written: liba.rmeta"}
```
The functionality is behind the `-Z emit-directives` option, and also
requires `--error-format=json`.
