Handle pretty printing of `else if let` clauses without ICEing
When pretty printing the HIR of `if ... {} else if let ... {}` clauses, this displays it the `else if let` part as `match` it gets desugared to, the same way normal `if let` statements are currently displayed, instead of ICEing.
```rust
pub fn main() {
if true {
// 1
} else if let a = 1 {
// 2
} else {
// 3
}
}
```
now gets desugared (via `rustc -Zunpretty=hir,typed src/x.rs`) to:
```rust
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
pub fn main() ({
(if (true as bool)
({
// 1
} as
()) else {match (1 as i32) {
a => {
// 2
}
_ => {
// 3
}
}} as ())
} as ())
```
For comparison, this code gets HIR prettyprinted the same way before and after this change:
```rust
pub fn main() {
if let a = 1 {
// 2
} else {
// 3
}
}
```
turns into
```rust
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
pub fn main() ({
(match (1 as i32) {
a => {
// 2
}
_ => {
// 3
}
} as ())
} as ())
```
This closes#82329. It closes#84434 as well, due to having the same root cause.
Give a better error when `std` or `core` are missing
- Suggest using `rustup target add` if `RUSTUP_HOME` is set. I don't know if there's any precedent for doing this, but it seems harmless enough and it will be a big help.
- On nightly, suggest using `cargo build -Z build-std` if `CARGO` is set
- Add a note about `#![no_std]` if `std` is missing but not core
- Add a note that std may be unsupported if `std` is missing but not core
Fixes https://github.com/rust-lang/rust/issues/84418.
r? `@petrochenkov`
- Suggest using `rustup target add` if `RUSTUP_HOME` is set. I don't know if there's any precedent for doing this, but it seems harmless enough and it will be a big help.
- Add a note about `#![no_std]` if `std` is missing but not core
- On nightly, suggest using `cargo build -Z build-std` if `CARGO` is set
- Add a note that std may be unsupported if `std` is missing but not core
- Don't suggest `#![no_std]` when the load isn't injected by the
compiler
various const parameter defaults improvements
Actually resolve names in const parameter defaults, fixing `struct Foo<const N: usize = { usize::MAX }>`.
---
Split generic parameter ban rib for types and consts, allowing
```rust
#![feature(const_generics_defaults)]
struct Q;
struct Foo<T = Q, const Q: usize = 3>(T);
```
---
Remove the type/const ordering restriction if `const_generics_defaults` is active, even if `const_generics` is not. allowing us to stabilize and test const param defaults separately.
---
Check well formedness of const parameter defaults, eagerly emitting an error for `struct Foo<const N: usize = { 0 - 1 }>`
---
Do not forbid const parameters in param defaults, allowing `struct Foo<const N: usize, T = [u8; N]>(T)` and `struct Foo<const N: usize, const M: usize = N>`. Note that this should not change anything which is stabilized, as on stable, type parameters must be in front of const parameters, which means that type parameter defaults are only allowed if no const parameters exist.
We still forbid generic parameters inside of const param types.
r? `@varkor` `@petrochenkov`
move core::hint::black_box under its own feature gate
The `black_box` function had its own RFC and is tracked separately from the `test` feature at https://github.com/rust-lang/rust/issues/64102. Let's reflect this in the feature gate.
To avoid breaking all the benchmarks, libtest's `test::black_box` is a wrapping definition, not a reexport -- this means it is still under the `test` feature gate.
Cautiously add IntoIterator for arrays by value
Add the attribute described in #84133, `#[rustc_skip_array_during_method_dispatch]`, which effectively hides a trait from method dispatch when the receiver type is an array.
Then cherry-pick `IntoIterator for [T; N]` from #65819 and gate it with that attribute. Arrays can now be used as `IntoIterator` normally, but `array.into_iter()` has edition-dependent behavior, returning `slice::Iter` for 2015 and 2018 editions, or `array::IntoIter` for 2021 and later.
r? `@nikomatsakis`
cc `@LukasKalbertodt` `@rust-lang/libs`
further split up const_fn feature flag
This continues the work on splitting up `const_fn` into separate feature flags:
* `const_fn_trait_bound` for `const fn` with trait bounds
* `const_fn_unsize` for unsizing coercions in `const fn` (looks like only `dyn` unsizing is still guarded here)
I don't know if there are even any things left that `const_fn` guards... at least libcore and liballoc do not need it any more.
`@oli-obk` are you currently able to do reviews?
Revert "rustdoc: Hide `#text` in doc-tests"
See discussion in #84502 - I'm worried that #84445 may cause a lot of breakages if this were to hit stable, so I think it's safer to revert and work on the known correct fix#84478.
Implement a lint that highlights all moves larger than a configured limit
Tracking issue: #83518
[MCP 420](https://github.com/rust-lang/compiler-team/issues/420) still ~blazing~ in progress
r? ```@pnkfelix```
The main open issue I see with this minimal impl of the feature is that the lint is immediately "stable" (so it can be named on stable), even if it is never executed on stable. I don't think we have the concept of unstable lint names or hiding lint names without an active feature gate, so that would be a bigger change.
Use details tag for trait implementors.
Part of #83332 and following on from #83337 and #83355.
This removes one category of JS-generated toggles (implementors), and replaces them with a `<details>` tag. This simplifies the JS, and fixes some bugs where things that were supposed to be hidden by the toggle were not hidden. Compare https://hoffman-andrews.com/rust/details-implementors/std/io/trait.Read.html#impl-Read vs https://doc.rust-lang.org/nightly/std/io/trait.Read.html#implementors.
This introduces a `left: -23px` to put the toggle in the correct place, matching the current style for `.collapse-toggle`.
It's worth noting this introduces a slight behavior change: since the entire line is now a `<summary>`, any part of the line is clickable. So for instance, in `impl Read for File`, clicking `impl` or `for` will collapse / expand the docs. Clicking `Read` or `File` still links to the appropriate documentation as before.
rustdoc: Convert sub-variant toggle to HTML
Instead of creating a JS toggle, this injects details/summary for
sub-variants of enums. This also fixes the CSS so that the toggle button
does not jump when expanding/collapsing.
Takes inspiration from #83337 and should be considered part of #83332. Not quite sure if the `.sub-variant` selectors could be further simplified? AFAICS it is only used in that place, and that does not seem to allow any recursion.
rustc: Use LLVM's new saturating float-to-int intrinsics
This commit updates rustc, with an applicable LLVM version, to use
LLVM's new `llvm.fpto{u,s}i.sat.*.*` intrinsics to implement saturating
floating-point-to-int conversions. This results in a little bit tighter
codegen for x86/x86_64, but the main purpose of this is to prepare for
upcoming changes to the WebAssembly backend in LLVM where wasm's
saturating float-to-int instructions will now be implemented with these
intrinsics.
This change allows simplifying a good deal of surrounding code, namely
removing a lot of wasm-specific behavior. WebAssembly no longer has any
special-casing of saturating arithmetic instructions and the need for
`fptoint_may_trap` is gone and all handling code for that is now
removed. This means that the only wasm-specific logic is in the
`fpto{s,u}i` instructions which only get used for "out of bounds is
undefined behavior". This does mean that for the WebAssembly target
specifically the Rust compiler will no longer be 100% compatible with
pre-LLVM 12 versions, but it seems like that's unlikely to be relied on
by too many folks.
Note that this change does immediately regress the codegen of saturating
float-to-int casts on WebAssembly due to the specialization of the LLVM
intrinsic not being present in our LLVM fork just yet. I'll be following
up with an LLVM update to pull in those patches, but affects a few other
SIMD things in flight for WebAssembly so I wanted to separate this change.
Eventually the entire `cast_float_to_int` function can be removed when
LLVM 12 is the minimum version, but that will require sinking the
complexity of it into other backends such as Cranelfit.
rustdoc: Hide `#text` in doc-tests
Since `#![attr]` and `#[attr]` are the only valid syntax that start with `#`, we can just special case those two tokens.
Fixes https://github.com/rust-lang/rust/issues/83284.
Check for intrinsics before coercing to a function pointer
Return an error if coercing function items / non-capturing closures
to a common function pointer type would require reifying an intrinsic.
Turns ICE reported in #84297 into a proper error.
Write Rustdoc titles like "x in crate::mod - Rust"
This makes Rustdoc titles for items be like "Widget in cratename::blah::foo - Rust". Titles for modules and other non-items are unchanged, and still read like "cratename::blah::foo - Rust". This makes managing several open Rustdoc tabs easier.
This also adds some tests for the new title behavior.
Closes#84371.
This makes Rustdoc titles for items read like
"x in cratename::blah::foo - Rust". Title for modules and other
non-items are unchanged, and still read like
"doccratenameconst::blah::foo - Rust". This makes managing several open
Rustdoc tabs easier.
Closes#84371.
Suggest `.as_ref()` on borrow error involving `Option`/`Result`
When encountering a E0382 borrow error involving an `Option` or `Result`
provide a suggestion to use `.as_ref()` on the prior move location to
avoid the move.
Fix#84165.
