In cases where it is legal, we should prefer poison values over
undef values.
This replaces undef with poison for aggregate construction and
for uninhabited types. There are more places where we can likely
use poison, but I wanted to stay conservative to start with.
In particular the aggregate case is important for newer LLVM
versions, which are not able to handle an undef base value during
early optimization due to poison-propagation concerns.
Flatten/inline format_args!() and (string and int) literal arguments into format_args!()
Implements https://github.com/rust-lang/rust/issues/78356
Gated behind `-Zflatten-format-args=yes`.
Part of #99012
This change inlines string literals, integer literals and nested format_args!() into format_args!() during ast lowering, making all of the following pairs result in equivalent hir:
```rust
println!("Hello, {}!", "World");
println!("Hello, World!");
```
```rust
println!("[info] {}", format_args!("error"));
println!("[info] error");
```
```rust
println!("[{}] {}", status, format_args!("error: {}", msg));
println!("[{}] error: {}", status, msg);
```
```rust
println!("{} + {} = {}", 1, 2, 1 + 2);
println!("1 + 2 = {}", 1 + 2);
```
And so on.
This is useful for macros. E.g. a `log::info!()` macro could just pass the tokens from the user directly into a `format_args!()` that gets efficiently flattened/inlined into a `format_args!("info: {}")`.
It also means that `dbg!(x)` will have its file, line, and expression name inlined:
```rust
eprintln!("[{}:{}] {} = {:#?}", file!(), line!(), stringify!(x), x); // before
eprintln!("[example.rs:1] x = {:#?}", x); // after
```
Which can be nice in some cases, but also means a lot more unique static strings than before if dbg!() is used a lot.
error-msg: impl better suggestion for `E0532`
Fixes#106862
No test as there is already a test which is nearly identical to the example in the linked issue.
Revert #107376 to fix potential `bincode` breakage and `rustc-perf` benchmark.
#107376 caused `rustc-perf`'s `webrender` benchmark to break, by regressing on the `bincode-1.3.3` crate.
~~This PR is a draft revert in case we can't land a fix soon enough, and we'd like to land the revert instead~~
(Though I myself think it'd be safer to do the revert, and run crater when relanding #107376.)
cc `@aliemjay`
Implement checked Shl/Shr at MIR building.
This does not require any special handling by codegen backends,
as the overflow behaviour is entirely determined by the rhs (shift amount).
This allows MIR ConstProp to remove the overflow check for constant shifts.
~There is an existing different behaviour between cg_llvm and cg_clif (cc `@bjorn3).`
I took cg_llvm's one as reference: overflow if `rhs < 0 || rhs > number_of_bits_in_lhs_ty`.~
EDIT: `cg_llvm` and `cg_clif` implement the overflow check differently. This PR uses `cg_llvm`'s implementation based on a `BitAnd` instead of `cg_clif`'s one based on an unsigned comparison.
Rollup of 7 pull requests
Successful merges:
- #108991 (add `enable-warnings` flag for llvm, and disable it by default.)
- #109109 (Use `unused_generic_params` from crate metadata)
- #109111 (Create dirs for build_triple)
- #109136 (Simplify proc macro signature validity check)
- #109150 (Update cargo)
- #109154 (Fix MappingToUnit to support no span of arg_ty)
- #109157 (Remove mw from review rotation for a while)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Simplify proc macro signature validity check
Use an `ObligationCtxt` instead of `normalize_erasing_regions` + `DeepRejectCtxt`. This should both give us a more accurate error message, and also avoid issues like not-well-formed proc macro signatures. Also, let's fall back on the regular type mismatch error reporting for making these diagnostic notes, instead of hard-coding a bunch of specific diagnostics.
Fixes#109129
Use `unused_generic_params` from crate metadata
Due to the way that `separate_provide_extern` interacted with the implementation of `<ty::InstanceDef<'tcx> as Key>::query_crate_is_local`, we actually never hit the foreign provider for `unused_generic_params`.
Additionally, since the *local* provider of `unused_generic_params` calls `should_polymorphize`, which always returns false if the def-id is foreign, this means that we never actually polymorphize monomorphic instances originating from foreign crates.
We don't actually encode `unused_generic_params` for items where all generics are used, so I had to tweak the foreign provider to fall back to `ty::UnusedGenericParams::new_all_used()` to avoid more ICEs when the above bugs were fixed.
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
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 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.
