- only borrow the refcell once per loop
- avoid complex matches to reduce branch paths in the hot loop
- use a by-ref fast path that avoids mutations at the expense of having false negatives
Use index based drop loop for slices and arrays
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.
Install projection from RPITIT to default trait method opaque correctly
1. For new lowering strategy `-Zlower-impl-trait-in-trait-to-assoc-ty`, install the correct default trait method projection predicates (RPITIT -> opaque). This makes default trait body tests pass!
2. Fix two WF-checking bugs -- first, we want to make sure that we're always looking for an opaque type in `check_return_position_impl_trait_in_trait_bounds`. That's because the RPITIT projections are normalized to opaques during wfcheck. Second, fix RPITIT's param-envs by not adding the projection predicates that we install on trait methods to make default RPITITs work -- I left a comment why.
3. Also, just a small drive-by for `rustc_on_unimplemented`. Not sure if it affects any tests, but can't hurt.
r? ````@spastorino,```` based off of #109140
Fix riscv64 fuchsia LLVM target name
Currently, riscv64gc-unknown-fuchsia (added in #108722) sets riscv64*gc*-unknown-fuchsia as the LLVM target.
1716932743/compiler/rustc_target/src/spec/riscv64gc_unknown_fuchsia.rs (L5)
However, riscv64*gc*-\* is not a valid LLVM target and causes the following error.
```console
$ rustc --print cfg --target riscv64gc-unknown-fuchsia
error: could not create LLVM TargetMachine for triple: riscv64gc-unknown-fuchsia: No available targets are compatible with triple "riscv64gc-unknown-fuchsia"
```
As with other RISC-V targets, the LLVM target should use riscv64-\*, not riscv64*gc*-\*.
1716932743/compiler/rustc_target/src/spec/riscv64gc_unknown_freebsd.rs (L5)1716932743/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_gnu.rs (L5)
I confirmed that riscv64-unknown-fuchsia is recognized as a valid LLVM target by using custom targets.
```console
# create a custom target with `"llvm-target": "riscv64-unknown-fuchsia" from no-std riscv64gc target.
$ rustc --print target-spec-json -Z unstable-options --target riscv64gc-unknown-none-elf | grep -v is-builtin | sed 's/"llvm-target".*/"llvm-target": "riscv64-unknown-fuchsia",/' > riscv64gc-unknown-fuchsia.json
$ rustc --print cfg --target riscv64gc-unknown-fuchsia.json
debug_assertions
panic="abort"
target_abi=""
target_arch="riscv64"
target_endian="little"
target_env=""
target_feature="a"
target_feature="c"
target_feature="d"
target_feature="f"
target_feature="m"
...
$ cat riscv64gc-unknown-fuchsia.json
{
"arch": "riscv64",
"code-model": "medium",
"cpu": "generic-rv64",
"data-layout": "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128",
"eh-frame-header": false,
"emit-debug-gdb-scripts": false,
"features": "+m,+a,+f,+d,+c",
"linker": "rust-lld",
"linker-flavor": "ld.lld",
"llvm-abiname": "lp64d",
"llvm-target": "riscv64-unknown-fuchsia",
"max-atomic-width": 64,
"panic-strategy": "abort",
"relocation-model": "static",
"supported-sanitizers": [
"kernel-address"
],
"target-pointer-width": "64"
}
# Check the current master's LLVM target name causes an error
$ sed -i 's/riscv64-unknown-fuchsia/riscv64gc-unknown-fuchsia/' riscv64gc-unknown-fuchsia.json
$ rustc --print cfg --target riscv64gc-unknown-fuchsia.json
error: could not create LLVM TargetMachine for triple: riscv64gc-unknown-fuchsia: No available targets are compatible with triple "riscv64gc-unknown-fuchsia"
```
r? ````@tmandry````
Remove box expressions from HIR
After #108516, `#[rustc_box]` is used at HIR->THIR lowering and this is no longer emitted, so it can be removed.
This is based on top of #108471 to help with conflicts, so 43490488ccacd1a822e9c621f5ed6fca99959a0b is the only relevant commit (sorry for all the duplicated pings!)
````@rustbot```` label +S-blocked
Wrap the whole LocalInfo in ClearCrossCrate.
MIR contains a lot of information about locals. The primary purpose of this information is the quality of borrowck diagnostics.
This PR aims to drop this information after MIR analyses are finished, ie. starting from post-cleanup runtime MIR.
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.
