Replace if-let and while-let with `if let` and `while let`
This pull request replaces if-let and while-let with `if let` and `while let`.
closes https://github.com/rust-lang/rust/issues/82205
The `rustc_data_structures::sync::OnceCell` is thread-safe when building
a parallel compiler. This is unnecessary for the purposes of pattern
usefulness checking. Use `!Sync` `std::lazy::OnceCell` instead.
Use debug log level for developer oriented logs
The information logged here is of limited general interest, while at the
same times makes it impractical to simply enable logging and share the
resulting logs due to the amount of the output produced.
Reduce log level from info to debug for developer oriented information.
For example, when building cargo, this reduces the amount of logs
generated by `RUSTC_LOG=info cargo build` from 265 MB to 79 MB.
Continuation of changes from 81350.
The information logged here is of limited general interest, while at the
same times makes it impractical to simply enable logging and share the
resulting logs due to the amount of the output produced.
Reduce log level from info to debug for developer oriented information.
For example, when building cargo, this reduces the amount of logs
generated by `RUSTC_LOG=info cargo build` from 265 MB to 79 MB.
Continuation of changes from 81350.
Reduce log level used by tracing instrumentation from info to debug
Restore log level to debug to avoid make info log level overly verbose (the uses of instrument attribute modified there, were for the most part a replacement for `debug!`; one use was novel).
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like "&*" instead of just "*".
Identify unreachable subpatterns more reliably
In https://github.com/rust-lang/rust/pull/80104 I used `Span`s to identify unreachable sub-patterns in the presence of or-patterns during exhaustiveness checking. In https://github.com/rust-lang/rust/issues/80501 it was revealed that `Span`s are complicated and that this was not a good idea.
Instead, this PR identifies subpatterns logically: as a path in the tree of subpatterns of a given pattern. I made a struct that captures a set of such subpatterns. This is a bit complex, but thankfully self-contained; the rest of the code does not need to know anything about it.
Fixes https://github.com/rust-lang/rust/issues/80501. I think I managed to keep the perf neutral.
r? `@varkor`
2229: Fix issues with move closures and mutability
This PR fixes two issues when feature `capture_disjoint_fields` is used.
1. Can't mutate using a mutable reference
2. Move closures try to move value out through a reference.
To do so, we
1. Compute the mutability of the capture and store it as part of the `CapturedPlace` that is written in TypeckResults
2. Restrict capture precision. Note this is temporary for now, to allow the feature to be used with move closures and ByValue captures and might change depending on discussions with the lang team.
- No Derefs are captured for ByValue captures, since that will result in value behind a reference getting moved.
- No projections are applied to raw pointers since these require unsafe blocks. We capture
them completely.
r? `````@nikomatsakis`````
Support FRU pattern with `[feature(capture_disjoint_fields)]`
In case of a functional record update syntax for creating a structure, `ExprUseVisitor` to only detect the precise use of some of the field in the `..x` part of the syntax. However, when we start building MIR, we
1. First, build the place for `x`
2. and then, add precise field projections so that only some parts of `x` end up getting read.
When `capture_disjoint_fields` is enabled, and FRU is used within a closure `x` won't be completely captured, and therefore the first step will fail. This PR updates `mir_build` to create a place builder in the first step and then create place from the builder only after applying the field projection.
Closes https://github.com/rust-lang/project-rfc-2229/issues/32
r? ``````@nikomatsakis``````
When `capture_disjoint_fields` is not enabled, checking if the root variable
binding is mutable would suffice.
However with the feature enabled, the captured place might be mutable
because it dereferences a mutable reference.
This PR computes the mutability of each capture after capture analysis
in rustc_typeck. We store this in `ty::CapturedPlace` and then use
`ty::CapturedPlace::mutability` in mir_build and borrow_check.
Refractor a few more types to `rustc_type_ir`
In the continuation of #79169, ~~blocked on that PR~~.
This PR:
- moves `IntVarValue`, `FloatVarValue`, `InferTy` (and friends) and `Variance`
- creates the `IntTy`, `UintTy` and `FloatTy` enums in `rustc_type_ir`, based on their `ast` and `chalk_ir` equilavents, and uses them for types in the rest of the compiler.
~~I will split up that commit to make this easier to review and to have a better commit history.~~
EDIT: done, I split the PR in commits of 200-ish lines each
r? `````@nikomatsakis````` cc `````@jackh726`````
implement ptr::write without dedicated intrinsic
This makes `ptr::write` more consistent with `ptr::write_unaligned`, `ptr::read`, `ptr::read_unaligned`, all of which are implemented in terms of `copy_nonoverlapping`.
This means we can also remove `move_val_init` implementations in codegen and Miri, and its special handling in the borrow checker.
Also see [this Zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/ptr.3A.3Aread.20vs.20ptr.3A.3Awrite).
Rust prints "type `&A` is non-empty" even is A is empty.
This is the intended behavior, but can be confusing.
This commit adds a note to non-exhaustive pattern errors if they are a
reference to something uninhabited.
I did not add tests to check that the note is not shown for
non-references or inhabited references, because this is already done
in other tests.
Maybe the added test is superfluous, because
`always-inhabited-union-ref` already checks for this case.
This does not handle &&Void or &&&void etc. I could add those as special
cases as well and ignore people who need quadruple
references.
Fixes#78123
