bors [Wed, 25 May 2022 16:39:37 +0000 (16:39 +0000)]
Auto merge of #97401 - Dylan-DPC:rollup-fh9e61o, r=Dylan-DPC
Rollup of 5 pull requests
Successful merges:
- #97302 (Do writeback of Closure params before visiting the parent expression)
- #97328 (rustc: Fix ICE in native library error reporting)
- #97351 (Output correct type responsible for structural match violation)
- #97398 (Add regression test for #82830)
- #97400 (Fix a typo on Struct `Substructure`)
Dylan DPC [Wed, 25 May 2022 15:37:21 +0000 (17:37 +0200)]
Rollup merge of #97351 - b-naber:adt-const-params-structural-match-violation, r=michaelwoerister
Output correct type responsible for structural match violation
Previously we included the outermost type that caused a structural match violation in the error message and stated that that type must be annotated with `#[derive(Eq, PartialEq)]` even if it already had that annotation. This PR outputs the correct type in the error message.
Dylan DPC [Wed, 25 May 2022 15:37:18 +0000 (17:37 +0200)]
Rollup merge of #97302 - compiler-errors:writeback-ascending, r=cjgillot
Do writeback of Closure params before visiting the parent expression
This means that given the expression:
```
let x = |a: Vec<_>| {};
```
We will visit the HIR node for `a` before `x`, and report the ambiguity on the former instead of the latter. This also moves writeback for struct field ids and const blocks before, but the ordering of this and walking the expr doesn't seem to matter.
This change was accepted in https://rust-lang.github.io/rfcs/2580-ptr-meta.html
Note that this changes the signature of **stable** functions. The change should be backward-compatible, but it is **insta-stable** since it cannot (easily, at all?) be made available only through a `#![feature(…)]` opt-in.
The RFC also proposed the same change for `NonNull::dangling`, which makes sense it terms of its signature but not in terms of its implementation. `dangling` uses `align_of()` as an address. But what `align_of()` should be for extern types or whether it should be allowed at all remains an open question.
This commit depends on https://github.com/rust-lang/rust/pull/93977, which is not yet part of the bootstrap compiler. So `#[cfg]` is used to only apply the change in stage 1+. As far a I know bounds cannot be made conditional with `#[cfg]`, so the entire functions are duplicated. This is unfortunate but temporary.
Since this duplication makes it less obvious in the diff, the new definitions differ in:
* More permissive bounds (`Thin` instead of implied `Sized`)
* Different implementation
* Having `rustc_allow_const_fn_unstable(const_fn_trait_bound)`
* Having `rustc_allow_const_fn_unstable(ptr_metadata)`
Dylan DPC [Wed, 25 May 2022 08:48:31 +0000 (10:48 +0200)]
Rollup merge of #97384 - nnethercote:fix-metadata-stats, r=bjorn3
Fix metadata stats.
This commit:
- Counts some things that weren't being counted previously, and adds
an assertion that ensure everything is counted.
- Reorders things so the `eprintln`s order matches the code order.
- Adds percentages, and makes clear that the zero bytes count is orthogonal to
the other measurements.
Dylan DPC [Wed, 25 May 2022 08:48:27 +0000 (10:48 +0200)]
Rollup merge of #95953 - JakobDegen:repeat-leak, r=oli-obk
Modify MIR building to drop repeat expressions with length zero
Closes #74836 .
Previously, when a user wrote `[foo; 0]` we used to simply leak `foo`. The goal is to fix that. This PR changes MIR building to make `[foo; 0]` equivalent to `{ drop(foo); [] }` in all cases. Of course, this is a breaking change (see below). A crater run did not indicate any regressions though, and given that the previous behavior was almost definitely not what any user wanted, it seems unlikely that anyone was relying on this.
Note that const generics are in general unaffected by this. Inserting the extra `drop` is only meaningful/necessary when `foo` is of a non-`Copy` type, and array repeat expressions with const generic repetition count must always be `Copy`.
Besides the obvious change to behavior associated with the additional drop, there are three categories of examples where this also changes observable behavior. In all of these cases, the new behavior is consistent with what you would get by replacing `[foo; 0]` with `{ drop(foo); [] }`. As such, none of these give the user new powers to express more things.
This compiles on stable today. Because we now introduce the drop of `String`, this no longer compiles as `String` may not be dropped in a const context.
**Reduced dataflow (non-breaking)**:
```rust
let mut x: i32 = 0;
let r = &x;
let a = [r; 0];
x = 5;
let _b = a;
```
Borrowck rejects this code on stable because it believes there is dataflow between `a` and `r`, and so the lifetime of `r` has to extend to the last statement. This change removes the dataflow and the above code is allowed to compile.
**More const promotion (non-breaking)**:
```rust
let _v: &'static [String; 0] = &[String::new(); 0];
```
This does not compile today because `String` having drop glue keeps it from being const promoted (despite that drop glue never being executed). After this change, this is allowed to compile.
### Alternatives
A previous attempt at this tried to reduce breakage by various tricks. This is still a possibility, but given that crater showed no regressions it seems unclear why we would want to introduce this complexity.
Disallowing `[foo; 0]` completely is also an option, but obviously this is more of a breaking change. I do not know how often this is actually used though.
This commit:
- Counts some things that weren't being counted previously, and adds
an assertion that ensure everything is counted.
- Reorders things so the `eprintln`s order matches the code order.
- Adds percentages, and makes clear that the zero bytes count is orthogonal to
the other measurements.
bors [Wed, 25 May 2022 06:14:15 +0000 (06:14 +0000)]
Auto merge of #97382 - Dylan-DPC:rollup-2t4ov4z, r=Dylan-DPC
Rollup of 5 pull requests
Successful merges:
- #93604 (Make llvm-libunwind a per-target option)
- #97026 (Change orderings of `Debug` for the Atomic types to `Relaxed`.)
- #97105 (Add tests for lint on type dependent on consts)
- #97323 (Introduce stricter checks for might_permit_raw_init under a debug flag )
- #97379 (Add aliases for `current_dir`)
lcnr [Tue, 24 May 2022 07:22:24 +0000 (09:22 +0200)]
move fast reject test out of `SelectionContext::match_impl`.
`match_impl` has two call sites. For one of them (within `rematch_impl`)
the fast reject test isn't necessary, because any rejection would
represent a compiler bug.
This commit moves the fast reject test to the other `match_impl` call
site, in `assemble_candidates_from_impls`. This lets us move the fast
reject test outside the `probe` call in that function. This avoids the
taking of useless snapshots when the fast reject test succeeds, which
gives a performance win when compiling the `bitmaps` and `nalgebra`
crates.
Dylan DPC [Wed, 25 May 2022 05:31:45 +0000 (07:31 +0200)]
Rollup merge of #97379 - ear7h:master, r=thomcc
Add aliases for `current_dir`
Aliases were added for the equivalent C/C++ APIs for POSIX and Windows. Also, I added one for `pwd` which users may be more familiar with, from the command line.
Dylan DPC [Wed, 25 May 2022 05:31:44 +0000 (07:31 +0200)]
Rollup merge of #97323 - 5225225:strict_init_checks, r=oli-obk
Introduce stricter checks for might_permit_raw_init under a debug flag
This is intended to be a version of the strict checks tried out in #79296, but also checking number validity (under the assumption that `let _ = std::mem::uninitialized::<u32>()` is UB, which seems to be what https://github.com/rust-lang/unsafe-code-guidelines/issues/71 is leaning towards.)
Dylan DPC [Wed, 25 May 2022 05:31:42 +0000 (07:31 +0200)]
Rollup merge of #97026 - Nilstrieb:make-atomic-debug-relaxed, r=scottmcm
Change orderings of `Debug` for the Atomic types to `Relaxed`.
This reduces synchronization between threads when debugging the atomic types. Reducing the synchronization means that executions with and without the debug calls will be more consistent, making it easier to debug.
We discussed this on the Rust Community Discord with `@ibraheemdev` before.
bors [Wed, 25 May 2022 03:53:39 +0000 (03:53 +0000)]
Auto merge of #97376 - compiler-errors:lazy-polymorphic, r=jackh726
Make `Lazy*<T>` types in `rustc_metadata` not care about lifetimes until decode
This allows us to remove the `'tcx` lifetime from `CrateRoot`. This is necessary because of #97287, which makes the `'tcx` lifetime on `Ty` invariant instead of covariant, so [this hack](https://github.com/rust-lang/rust/blob/0a437b2ca081bc12425a3318cb66aade9824cbae/compiler/rustc_metadata/src/rmeta/decoder.rs#L89-92) no longer holds under that PR.
Introduces a trait called `ParameterizedOverTcx` which has a generic associated type that allows a type to be parameterized over that lifetime. This means we can decode, for example, `Lazy<Ty<'static>>` into any `Ty<'tcx>` depending on the `TyCtxt<'tcx>` we pass into the decode function.
Yuki Okushi [Tue, 24 May 2022 22:08:42 +0000 (07:08 +0900)]
Rollup merge of #97266 - est31:unknown_lints_cfg_attr, r=lcnr
Make weird name lints trigger behind cfg_attr
The weird name lints (`unknown_lints`, `renamed_and_removed_lints`), the lints that lint the linting, were previously not firing for lint level declarations behind `cfg_attr`, as they were only running before expansion.
Furthermore, this PR also makes the weird name lints respect level delcarations for *them* that were hidden by `cfg_attr`, making them consistent to other lints. So this will now not issue a warning:
ridwanabdillahi [Tue, 24 May 2022 18:14:48 +0000 (11:14 -0700)]
Add support for embedding pretty printers via the `#[debugger_visualizer]` attribute. Add tests for embedding pretty printers and update documentation.
Ensure all error checking for `#[debugger_visualizer]` is done up front and not when the `debugger_visualizer` query is run.
Clean up potential ODR violations when embedding pretty printers into the `__rustc_debug_gdb_scripts_section__` section.
bors [Tue, 24 May 2022 16:23:32 +0000 (16:23 +0000)]
Auto merge of #97356 - Dylan-DPC:rollup-bhceawj, r=Dylan-DPC
Rollup of 4 pull requests
Successful merges:
- #97288 (Lifetime variance fixes for rustdoc)
- #97298 (Parse expression after `else` as a condition if followed by `{`)
- #97308 (Stabilize `cell_filter_map`)
- #97321 (explain how to turn integers into fn ptrs)
David Wood [Mon, 23 May 2022 17:37:27 +0000 (18:37 +0100)]
typeck: use typed fluent identifiers for diags
Use new typed Fluent identifiers for the "missing type parameters"
diagnostic in the typeck crate which was manually creating
`DiagnosticMessage`s previously.
David Wood [Mon, 23 May 2022 17:24:55 +0000 (18:24 +0100)]
macros: introduce `fluent_messages` macro
Adds a new `fluent_messages` macro which performs compile-time
validation of the compiler's Fluent resources (i.e. that the resources
parse and don't multiply define the same messages) and generates
constants that make using those messages in diagnostics more ergonomic.
For example, given the following invocation of the macro..
```ignore (rust)
fluent_messages! {
typeck => "./typeck.ftl",
}
```
..where `typeck.ftl` has the following contents..
```fluent
typeck-field-multiply-specified-in-initializer =
field `{$ident}` specified more than once
.label = used more than once
.label-previous-use = first use of `{$ident}`
```
...then the macro parse the Fluent resource, emitting a diagnostic if it
fails to do so, and will generate the following code:
est31 [Sun, 22 May 2022 02:25:40 +0000 (04:25 +0200)]
Emit weird lint name lints after expansion
Previously, we were emitting weird name lints (for renamed or unknown lints)
before expansion, most importantly before cfg expansion.
This meant that the weird name lints would not fire
for lint attributes hidden inside cfg_attr. The same applied
for lint level specifications of those lints.
By moving the lints for the lint names to the post-expansion
phase, these issues are resolved.
Dylan DPC [Tue, 24 May 2022 13:58:26 +0000 (15:58 +0200)]
Rollup merge of #97321 - RalfJung:int-to-fnptr, r=Dylan-DPC
explain how to turn integers into fn ptrs
(with an intermediate raw ptr, not a direct transmute)
Direct int2ptr transmute, under the semantics I am imagining, will produce a ptr with "invalid" provenance that is invalid to deref or call. We cannot give it the same semantics as int2ptr casts since those do [something complicated](https://www.ralfj.de/blog/2022/04/11/provenance-exposed.html).
To my great surprise, that is already what the example in the `transmute` docs does. :) I still added a comment to say that that part is important, and I added a section explicitly talking about this to the `fn()` type docs.
With https://github.com/rust-lang/miri/pull/2151, Miri will start complaining about direct int-to-fnptr transmutes (in the sense that it is UB to call the resulting pointer).
Dylan DPC [Tue, 24 May 2022 13:58:24 +0000 (15:58 +0200)]
Rollup merge of #97298 - compiler-errors:if-else-stmt-braces, r=davidtwco
Parse expression after `else` as a condition if followed by `{`
Fixes #49361.
Two things:
1. This wording needs help. I can never find a natural/intuitive phrasing when I write diagnostics :sweat_smile:
2. Do we even want to show the "wrap in braces" case? I would assume most of the time the "add an `if`" case is the right one.
Dylan DPC [Tue, 24 May 2022 13:58:24 +0000 (15:58 +0200)]
Rollup merge of #97288 - compiler-errors:tcxify-rustdoc, r=Dylan-DPC
Lifetime variance fixes for rustdoc
#97287 migrates rustc to a `Ty` type that is invariant over its lifetime `'tcx`, so I need to fix a bunch of places that assume that `Ty<'a>` and `Ty<'b>` can be unified by shortening both to some common lifetime.
This is doable, since everything is already `'tcx`, so all this PR does is be a bit more explicit that elided lifetimes are actually `'tcx`.
Split out from #97287 so the rustdoc team can review independently.
bors [Tue, 24 May 2022 13:42:33 +0000 (13:42 +0000)]
Auto merge of #97291 - compiler-errors:lazy-is-actually-3-types-in-a-trenchcoat, r=cjgillot
Split out the various responsibilities of `rustc_metadata::Lazy`
`Lazy<T>` actually acts like three different types -- a pointer in the crate metadata to a single value, a pointer to a list/array of values, and an indexable pointer of a list of values (a table).
We currently overload `Lazy<T>` to work differently than `Lazy<[T]>` and the same for `Lazy<Table<I, T>>`. All is well with some helper adapter traits such as [`LazyQueryDecodable`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_metadata/rmeta/decoder/trait.LazyQueryDecodable.html) and [`EncodeContentsForLazy`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_metadata/rmeta/encoder/trait.EncodeContentsForLazy.html).
Well, changes in #97287 that make `Lazy` work with the now invariant lifetime `'tcx` make these adapters fall apart because of coherence reasons. So we split out these three types and rework some of the helper traits so it's both 1. more clear to understand, and 2. compatible with the changes later in that PR.
Split out from #97287 so it can be reviewed separately, since this PR stands on its own.