Format all the let-chains in compiler crates
Since rust-lang/rustfmt#5910 has landed, soon we will have support for formatting let-chains (as soon as rustfmt syncs and beta gets bumped).
This PR applies the changes [from master rustfmt to rust-lang/rust eagerly](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/out.20formatting.20of.20prs/near/374997516), so that the next beta bump does not have to deal with a 200+ file diff and can remain concerned with other things like `cfg(bootstrap)` -- #113637 was a pain to land, for example, because of let-else.
I will also add this commit to the ignore list after it has landed.
The commands that were run -- I'm not great at bash-foo, but this applies rustfmt to every compiler crate, and then reverts the two crates that should probably be formatted out-of-tree.
```
~/rustfmt $ ls -1d ~/rust/compiler/* | xargs -I@ cargo run --bin rustfmt -- `@/src/lib.rs` --config-path ~/rust --edition=2021 # format all of the compiler crates
~/rust $ git checkout HEAD -- compiler/rustc_codegen_{gcc,cranelift} # revert changes to cg-gcc and cg-clif
```
cc `@rust-lang/rustfmt`
r? `@WaffleLapkin` or `@Nilstrieb` who said they may be able to review this purely mechanical PR :>
cc `@Mark-Simulacrum` and `@petrochenkov,` who had some thoughts on the order of operations with big formatting changes in https://github.com/rust-lang/rust/pull/95262#issue-1178993801. I think the situation has changed since then, given that let-chains support exists on master rustfmt now, and I'm fairly confident that this formatting PR should land even if *bootstrap* rustfmt doesn't yet format let-chains in order to lessen the burden of the next beta bump.
Relate alias ty with variance
In the new solver, turns out that the subst-relate branch of the alias-relate predicate was relating args invariantly even for opaques, which have variance 💀.
This change is a bit more invasive, but I'd rather not special-case it [here](aeaa5c30e5/compiler/rustc_trait_selection/src/solve/alias_relate.rs (L171-L190)) and then have it break elsewhere. I'm doing a perf run to see if the extra call to `def_kind` is that expensive, if it is, I'll reconsider.
r? ``@lcnr``
Bring back generic parameters for indices in rustc_abi and make it compile on stable
This effectively reverses https://github.com/rust-lang/rust/pull/107163, allowing rust-analyzer to depend on this crate again,
It also moves some glob imports / expands them in the first commit because they made it more difficult for me to reason about things.
Remove the `TypedArena::alloc_from_iter` specialization.
It was added in #78569. It's complicated and doesn't actually help
performance.
r? `@cjgillot`
a small wf and clause cleanup
- remove `Clause::from_projection_clause`, instead use `ToPredicate`
- change `predicate_obligations` to directly take a `Clause`
- remove some unnecessary `&`
- use clause in `min_specialization` checks where easily applicable
Don't store lazyness in `DefKind::TyAlias`
1. Don't store lazyness of a type alias in its `DefKind`, but instead via a query.
2. This allows us to treat type aliases as lazy if `#[feature(lazy_type_alias)]` *OR* if the alias contains a TAIT, rather than having checks for both in separate parts of the codebase.
r? `@oli-obk` cc `@fmease`
adjust how closure/generator types are printed
I saw `&[closure@$DIR/issue-20862.rs:2:5]` and I thought it is a slice type, because that's usually what `&[_]` is... it took me a while to realize that this is just a confusing printer and actually there's no slice. Let's use something that cannot be mistaken for a regular type.
Suggest desugaring to return-position `impl Future` when an `async fn` in trait fails an auto trait bound
First commit allows us to store the span of the `async` keyword in HIR.
Second commit implements a suggestion to desugar an `async fn` to a return-position `impl Future` in trait to slightly improve the `Send` situation being discussed in #115822.
This suggestion is only made when `#![feature(return_type_notation)]` is not enabled -- if it is, we should instead suggest an appropriate where-clause bound.
coverage: Don't bother renumbering expressions on the Rust side
The LLVM API that we use to encode coverage mappings already has its own code for removing unused coverage expressions and renumbering the rest.
This lets us get rid of our own complex renumbering code, making it easier to change our coverage code in other ways.
---
Now that we have tests for coverage mappings (#114843), I've been able to verify that this PR doesn't make the coverage mappings worse, thanks to an explicit simplification step.
rename mir::Constant -> mir::ConstOperand, mir::ConstKind -> mir::Const
Also, be more consistent with the `to/eval_bits` methods... we had some that take a type and some that take a size, and then sometimes the one that takes a type is called `bits_for_ty`.
Turns out that `ty::Const`/`mir::ConstKind` carry their type with them, so we don't need to even pass the type to those `eval_bits` functions at all.
However this is not properly consistent yet: in `ty` we have most of the methods on `ty::Const`, but in `mir` we have them on `mir::ConstKind`. And indeed those two types are the ones that correspond to each other. So `mir::ConstantKind` should actually be renamed to `mir::Const`. But what to do with `mir::Constant`? It carries around a span, that's really more like a constant operand that appears as a MIR operand... it's more suited for `syntax.rs` than `consts.rs`, but the bigger question is, which name should it get if we want to align the `mir` and `ty` types? `ConstOperand`? `ConstOp`? `Literal`? It's not a literal but it has a field called `literal` so it would at least be consistently wrong-ish...
``@oli-obk`` any ideas?
The LLVM API that we use to encode coverage mappings already has its own code
for removing unused coverage expressions and renumbering the rest.
This lets us get rid of our own complex renumbering code, making it easier to
change our coverage code in other ways.
adjust ConstValue::Slice to work for arbitrary slice types
valtrees have already been assuming that this works; this PR makes it a reality. Also further restrict `ConstValue::Slice` to what it is actually used for; this even shrinks `ConstValue` from 32 to 24 bytes which is a nice win. :)
The alternative to this approach is to make `ConstValue::Slice` work really only for `&str`/`&[u8]` literals, and never return it in `op_to_const`. That would make `op_to_const` very clean. We could then even remove the `meta` field; the length would always be `data.inner().len()`. We could *almost* just use a `Symbol` instead of a `ConstAllocation`, but we have to support byte strings and there doesn't seem to be an interned representation of them (or rather, `ConstAllocation` *is* their interned representation). In this world, valtrees of slice reference types would then become noticeably more expensive to turn into a `ConstValue` -- but does that matter? Specifically for `&str`/`&[u8]` we could still use the optimized representation if we wanted.
If byte strings were already interned somewhere I'd gravitate towards the alternative, but the way things stand, we need a `ConstAllocation` case anyway to support byte strings, and then we might as well support arbitrary slices. (Or we say that byte strings don't get an optimized representation at all. Such a performance cliff between `str` and byte strings is probably unexpected, though due to the lack of interning for byte strings I think there might already be a performance cliff there.)
clean up unneeded `ToPredicate` impls
Part of #107250.
Removed all totally unused impls. And inlined two impls not need to satisify trait bound.
r? `@oli-obk`
Pretty-print argument-position impl trait to name it.
This removes a corner case.
RPIT and TAIT keep having no name, and it would be wrong to use the one in HIR (Ident::empty), so I make this case ICE.
rustc_target/riscv: Fix passing of transparent unions with only one non-ZST member
This ensures that `MaybeUninit<T>` has the same ABI as `T` when passed through an `extern "C"` function.
Fixes https://github.com/rust-lang/rust/issues/115481.
r? `@RalfJung`
move things out of mir/mod.rs
This moves a bunch of things out of `mir/mod.rs`:
- all const-related stuff to a new file consts.rs
- all statement/place/operand-related stuff to a new file statement.rs
- all pretty-printing related stuff to pretty.rs
`mod.rs` started out with 3100 lines and ends up with 1600. :)
Also there was some pretty-printing stuff in terminator.rs, that also got moved to pretty.rs, and I reordered things in pretty.rs so that it can be grouped by functionality.
Only the commit "use pretty_print_const_value from MIR constant 'extra' printing" has any behavior changes; it resolves the issue of having a fancy and a very crude pretty-printer for `ConstValue`.
r? `@oli-obk`
