Ensure `ptr::read` gets all the same LLVM `load` metadata that dereferencing does
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`. Trying to narrow it down, it seems that was because `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
The root cause is that `ptr::read` is currently implemented via the *untyped* `copy_nonoverlapping`, and thus the `load` doesn't get any type-aware metadata: no `noundef`, no `!range`. This PR solves that by lowering `ptr::read(p)` to `copy *p` in MIR, for which the backends already do the right thing.
Fortuitiously, this also improves the IR we give to LLVM for things like `mem::replace`, and fixes a couple of long-standing bugs where `ptr::read` on `Copy` types was worse than `*`ing them.
Zulip conversation: <https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Move.20array.3A.3AIntoIter.20to.20ManuallyDrop/near/341189936>
cc `@erikdesjardins` `@JakobDegen` `@workingjubilee` `@the8472`
Fixes#106369Fixes#73258
14 commits in 7d3033d2e59383fd76193daf9423c3d141972a7d..4a3c588b1f0a8e2dc8dd8789dbf3b6a71b02ed49
2023-03-08 17:05:08 +0000 to 2023-03-14 14:05:36 +0000
- ci: make clean-test-output a script for reuse (rust-lang/cargo#11848)
- Accurately show status when downgrading dependencies (rust-lang/cargo#11839)
- docs(contrib): Move Design Principles earlier in the book (rust-lang/cargo#11842)
- docs(contrib): Point compilation docs to doc comments (rust-lang/cargo#11841)
- `cargo install --git` multiple packages with binaries found hint (rust-lang/cargo#11835)
- Disable flaky auth tests when `gitoxide` runs them (rust-lang/cargo#11830)
- Add some documentation on writing cross-compilation tests (rust-lang/cargo#11825)
- chore: Use sparse protocol on stable CI (rust-lang/cargo#11829)
- Notice for potential unexpected shell expansions in help text of `cargo-add` (rust-lang/cargo#11826)
- Add tracking issue to gitoxide unstable docs (rust-lang/cargo#11822)
- Bump crates-io to 0.36.0 (rust-lang/cargo#11820)
- Bump to 0.71.0; update changelog (rust-lang/cargo#11815)
- docs(contrib): Move overview to lib (rust-lang/cargo#11809)
- Fix semver check for 1.68 (rust-lang/cargo#11817)
Instead of building two kinds of drop pair loops, of which only one will
be eventually used at runtime in a given monomorphization, always use
index based loop.
Rollup of 9 pull requests
Successful merges:
- #108722 (Support for Fuchsia RISC-V target)
- #108880 (Remove tests/ui/impl-trait/in-trait/new-lowering-strategy in favor of using revisions on existing tests)
- #108909 (Fix object safety checks for new RPITITs)
- #108915 (Remove some direct calls to local_def_id_to_hir_id on diagnostics)
- #108923 (Make fns from other crates with RPITIT work for -Zlower-impl-trait-in-trait-to-assoc-ty)
- #109101 (Fall back to old metadata computation when type references errors)
- #109105 (Don't ICE for late-bound consts across `AnonConstBoundary`)
- #109110 (Don't codegen impossible to satisfy impls)
- #109116 (Emit diagnostic when calling methods on the unit type in method chains)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Emit diagnostic when calling methods on the unit type in method chains
Fixes#104204.
What this PR does: If a method is not found somewhere in a call chain, we check if we called earlier a method with signature `(&mut T, ...) -> ()`. If this is the case then we emit a diagnostic message.
For example given input:
```
vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
```
the current output is:
```
error[E0599]: no method named `sort` found for unit type `()` in the current scope
--> hello.rs:3:72
|
3 | vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
| ^^^^ method not found in `()`
```
after this PR it will be:
```
error[E0599]: no method named `sort` found for unit type `()` in the current scope
--> ./hello.rs:3:72
|
3 | vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
| ^^^^ method not found in `()`
|
note: method `sort_by_key` modifies its receiver in-place, it is not meant to be used in method chains.
--> ./hello.rs:3:53
|
3 | vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
| ^^^^^^^^^^^ this call modifies its receiver in-place
```
Fall back to old metadata computation when type references errors
Projection is a bit too aggressive normalizing `<dyn Trait<[type error]> as Pointee>::Metadata` to `[type error]`, rather than to `DynMetadata<..>`. Side-step that by just falling back to the old structural metadata computation.
Fixes#109078
Make fns from other crates with RPITIT work for -Zlower-impl-trait-in-trait-to-assoc-ty
Only the last two commits are meaningful.
r? `@compiler-errors`
Remove some direct calls to local_def_id_to_hir_id on diagnostics
Was playing with `tests/ui/impl-trait/in-trait/default-body-with-rpit.rs` and was able to remove some ICEs. Still getting ...
```
error[E0277]: `impl Future<Output = Foo::{opaque#0}>` is not a future
--> tests/ui/impl-trait/in-trait/default-body-with-rpit.rs:10:28
|
10 | async fn baz(&self) -> impl Debug {
| ^^^^^^^^^^ `impl Future<Output = Foo::{opaque#0}>` is not a future
|
= help: the trait `Future` is not implemented for `impl Future<Output = Foo::{opaque#0}>`
= note: impl Future<Output = Foo::{opaque#0}> must be a future or must implement `IntoFuture` to be awaited
note: required by a bound in `Foo::{opaque#1}`
--> tests/ui/impl-trait/in-trait/default-body-with-rpit.rs:10:28
|
10 | async fn baz(&self) -> impl Debug {
| ^^^^^^^^^^ required by this bound in `Foo::{opaque#1}`
error[E0277]: the size for values of type `impl Future<Output = Foo::{opaque#0}>` cannot be known at compilation time
--> tests/ui/impl-trait/in-trait/default-body-with-rpit.rs:10:28
|
10 | async fn baz(&self) -> impl Debug {
| ^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `impl Future<Output = Foo::{opaque#0}>`
note: required by a bound in `Foo::{opaque#1}`
--> tests/ui/impl-trait/in-trait/default-body-with-rpit.rs:10:28
|
10 | async fn baz(&self) -> impl Debug {
| ^^^^^^^^^^ required by this bound in `Foo::{opaque#1}`
error: internal compiler error: compiler/rustc_hir_typeck/src/closure.rs:724:18: async fn generator return type not an inference variable: Foo::{opaque#1}<'_>
--> tests/ui/impl-trait/in-trait/default-body-with-rpit.rs:10:39
|
10 | async fn baz(&self) -> impl Debug {
| _______________________________________^
11 | | ""
12 | | }
| |_____^
```
But I guess this is a little bit of progress anyway.
This one goes on top of #108700 and #108945
r? `@compiler-errors`
Remove tests/ui/impl-trait/in-trait/new-lowering-strategy in favor of using revisions on existing tests
r? `@compiler-errors`
This one again sits on top of existing approved PRs and it still needs to add revisions to tests in `tests/ui/impl-trait/in-trait` as it only does so for async in traits.
Support for Fuchsia RISC-V target
Fuchsia is in the process of implementing the RISC-V support. This change implements the minimal Rust compiler support. The support for building runtime libraries will be implemented in follow up changes once Fuchsia SDK has the RISC-V support.
If no method is found when checking method call, we check if we called a method with signature (&mut T, ...) -> (). If this is the case then we emit a diagnostic message
Properly allow macro expanded `format_args` invocations to uses captures
Originally, this was kinda half-allowed. There were some primitive checks in place that looked at the span to see whether the input was likely a literal. These "source literal" checks are needed because the spans created during `format_args` parsing only make sense when it is indeed a literal that was written in the source code directly.
This is orthogonal to the restriction that the first argument must be a "direct literal", not being exanpanded from macros. This restriction was imposed by [RFC 2795] on the basis of being too confusing. But this was only concerned with the argument of the invocation being a literal, not whether it was a source literal (maybe in spirit it meant it being a source literal, this is not clear to me).
Since the original check only really cared about source literals (which is good enough to deny the `format_args!(concat!())` example), macros expanding to `format_args` invocations were able to use implicit captures if they spanned the string in a way that lead back to a source string.
The "source literal" checks were not strict enough and caused ICEs in certain cases (see #106191). So I tightened it up in #106195 to really only work if it's a direct source literal.
This caused the `indoc` crate to break. `indoc` transformed the source literal by removing whitespace, which made it not a "source literal" anymore (which is required to fix the ICE). But since `indoc` spanned the literal in ways that made the old check think that it's a literal, it was able to use implicit captures (which is useful and nice for the users of `indoc`).
This commit properly seperates the previously introduced concepts of "source literal" and "direct literal" and therefore allows `indoc` invocations, which don't create "source literals" to use implicit captures again.
Fixes#106191
[RFC 2795]: https://rust-lang.github.io/rfcs/2795-format-args-implicit-identifiers.html#macro-hygiene
Sometimes, we want to create subspans and point at code in the literal
if possible. But this doesn't always make sense, sometimes the literal
may come from macro expanded code and isn't actually there in the
source. Then, we can't really make these suggestions.
This now makes sure that the literal is actually there as we see it so
that we will not run into ICEs on weird literal transformations.
