Better suggestions when user tries to collect into an unsized `[_]`
1. Extend the predicate on `rustc_on_unimplemented` to support substitutions like note, label, etc (i.e. treat it as a `OnUnimplementedFormatString`) so we can have slightly more general `rustc_on_unimplemented` special-cases.
2. Add a `rustc_on_unimplemented` if we fail on `FromIterator<A> for [A]` which happens when we don't explicitly collect into a `vec<A>`, but then pass the return from a `.collect` call into something that takes a slice.
Fixes#91423
Refactor query system to maintain a global job id counter
This replaces the per-shard counters with a single global counter, simplifying
the JobId struct down to just a u64 and removing the need to pipe a DepKind
generic through a bunch of code. The performance implications on non-parallel
compilers are likely minimal (this switches to `Cell<u64>` as the backing
storage over a `u64`, but the latter was already inside a `RefCell` so it's not
really a significance divergence). On parallel compilers, the cost of a single
global u64 counter may be more significant: it adds a serialization point in
theory. On the other hand, we can imagine changing the counter to have a
thread-local component if it becomes worrisome or some similar structure.
The new design is sufficiently simpler that it warrants the potential for slight
changes down the line if/when we get parallel compilation to be more of a
default.
A u64 counter, instead of u32 (the old per-shard width), is chosen to avoid
possibly overflowing it and causing problems; it is effectively impossible that
we would overflow a u64 counter in this context.
Delete -Zquery-stats infrastructure
These statistics are computable from the self-profile data and/or ad-hoc collectable as needed, and in the meantime contribute to rustc bootstrap times -- locally, this PR shaves ~2.5% from rustc_query_impl builds in instruction counts.
If this does lose some functionality we want to keep, I think we should migrate it to self-profile (or a similar interface) rather than this ad-hoc reporting.
Store rlink data in opaque binary format on disk
This removes one of the only uses of JSON decoding (to Rust structs) from the compiler, and fixes the FIXME comment. It's not clear to me what the reason for using JSON here originally was, and from what I can tell nothing outside of rustc expects to read the emitted information, so it seems like a reasonable step to move it to the metadata-encoding format (rustc_serialize::opaque).
Mostly intended as a FIXME fix, though potentially a stepping stone to dropping the support for Decodable to be used to decode JSON entirely (allowing for better/faster APIs on the Decoder trait).
cc #64191
Improve opaque type higher-ranked region error message under NLL
Currently, any higher-ranked region errors involving opaque types
fall back to a generic "higher-ranked subtype error" message when
run under NLL. This PR adds better error message handling for this
case, giving us the same kinds of error messages that we currently
get without NLL:
```
error: implementation of `MyTrait` is not general enough
--> $DIR/opaque-hrtb.rs:12:13
|
LL | fn foo() -> impl for<'a> MyTrait<&'a str> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `MyTrait` is not general enough
|
= note: `impl MyTrait<&'2 str>` must implement `MyTrait<&'1 str>`, for any lifetime `'1`...
= note: ...but it actually implements `MyTrait<&'2 str>`, for some specific lifetime `'2`
error: aborting due to previous error
```
To accomplish this, several different refactoring needed to be made:
* We now have a dedicated `InstantiateOpaqueType` struct which
implements `TypeOp`. This is used to invoke `instantiate_opaque_types`
during MIR type checking.
* `TypeOp` is refactored to pass around a `MirBorrowckCtxt`, which is
needed to report opaque type region errors.
* We no longer assume that all `TypeOp`s correspond to canonicalized
queries. This allows us to properly handle opaque type instantiation
(which does not occur in a query) as a `TypeOp`.
A new `ErrorInfo` associated type is used to determine what
additional information is used during higher-ranked region error
handling.
* The body of `try_extract_error_from_fulfill_cx`
has been moved out to a new function `try_extract_error_from_region_constraints`.
This allows us to re-use the same error reporting code between
canonicalized queries (which can extract region constraints directly
from a fresh `InferCtxt`) and opaque type handling (which needs to take
region constraints from the pre-existing `InferCtxt` that we use
throughout MIR borrow checking).
Drop tracking: track borrows of projections
Previous efforts to ignore partially consumed values meant we were also not considering borrows of a projection. This led to cases where we'd miss borrowed types which MIR expected to be there, leading to ICEs.
This PR also includes the `-Zdrop-tracking` flag from #93313. If that PR lands first, I'll rebase to drop the commit from this one.
Fixes#93648
rustc_query_impl: reduce visibility of some modules/fn's
Locally this reduces number of exported functions from 15221 -> 14952 and size a little.
Perf run please?
Remove defaultness from ImplItem.
This information is not really used anywhere, except HIR pretty-printing. This makes ImplItem and TraitItem more similar.
Rollup of 7 pull requests
Successful merges:
- #91950 (Point at type when a `static` `#[global_allocator]` doesn't `impl` `GlobalAlloc`)
- #92715 (Do not suggest char literal for zero-length strings)
- #92917 (Don't constrain projection predicates with inference vars in GAT substs)
- #93206 (Use `NtCreateFile` instead of `NtOpenFile` to open a file)
- #93732 (add fut/back compat tests for implied trait bounds)
- #93764 (⬆️ rust-analyzer)
- #93767 (deduplicate `lcnr` in mailmap)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This replaces the per-shard counters with a single global counter, simplifying
the JobId struct down to just a u64 and removing the need to pipe a DepKind
generic through a bunch of code. The performance implications on non-parallel
compilers are likely minimal (this switches to `Cell<u64>` as the backing
storage over a `u64`, but the latter was already inside a `RefCell` so it's not
really a significance divergence). On parallel compilers, the cost of a single
global u64 counter may be more significant: it adds a serialization point in
theory. On the other hand, we can imagine changing the counter to have a
thread-local component if it becomes worrisome or some similar structure.
The new design is sufficiently simpler that it warrants the potential for slight
changes down the line if/when we get parallel compilation to be more of a
default.
A u64 counter, instead of u32 (the old per-shard width), is chosen to avoid
possibly overflowing it and causing problems; it is effectively impossible that
we would overflow a u64 counter in this context.
Currently, any higher-ranked region errors involving opaque types
fall back to a generic "higher-ranked subtype error" message when
run under NLL. This PR adds better error message handling for this
case, giving us the same kinds of error messages that we currently
get without NLL:
```
error: implementation of `MyTrait` is not general enough
--> $DIR/opaque-hrtb.rs:12:13
|
LL | fn foo() -> impl for<'a> MyTrait<&'a str> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `MyTrait` is not general enough
|
= note: `impl MyTrait<&'2 str>` must implement `MyTrait<&'1 str>`, for any lifetime `'1`...
= note: ...but it actually implements `MyTrait<&'2 str>`, for some specific lifetime `'2`
error: aborting due to previous error
```
To accomplish this, several different refactoring needed to be made:
* We now have a dedicated `InstantiateOpaqueType` struct which
implements `TypeOp`. This is used to invoke `instantiate_opaque_types`
during MIR type checking.
* `TypeOp` is refactored to pass around a `MirBorrowckCtxt`, which is
needed to report opaque type region errors.
* We no longer assume that all `TypeOp`s correspond to canonicalized
queries. This allows us to properly handle opaque type instantiation
(which does not occur in a query) as a `TypeOp`.
A new `ErrorInfo` associated type is used to determine what
additional information is used during higher-ranked region error
handling.
* The body of `try_extract_error_from_fulfill_cx`
has been moved out to a new function `try_extract_error_from_region_constraints`.
This allows us to re-use the same error reporting code between
canonicalized queries (which can extract region constraints directly
from a fresh `InferCtxt`) and opaque type handling (which needs to take
region constraints from the pre-existing `InferCtxt` that we use
throughout MIR borrow checking).
Don't constrain projection predicates with inference vars in GAT substs
cc #91762
Not a fix, but a mitigation to prevent a backwards-compatible hazard where we normalize using a predicate only because it's the only one available, but shouldn't. This would constrain an inference variable which didn't really want. We already do this when selecting a projection candidate, which isn't always correct. But changing that is a problem for a different day.
Also found out that a suggestion for `await`ing a future was using the wrong substs.
r? ``@nikomatsakis``
Do not suggest char literal for zero-length strings
PR #92507 adds a hint to switch to single quotes when a char is expected and a single-character string literal is provided.
The check to ensure the string literal is one character long missed the 0-char case, and would incorrectly offer the hint.
This PR adds the missing check, and a test case to confirm the new behavior.
Add in ValuePair::Term
This adds in an enum when matching on positions which can either be types or consts.
It will default to emitting old special cased error messages for types.
r? `@oli-obk`
cc `@matthiaskrgr`
Fixes#93578
update comment wrt const param defaults
after #93669 i looked through all other uses of `GenericParamKind::Const` again to detect if we missed the `default` there as well, but afaict we really only missed lifetime resolution '^^ at least i found an outdated comment :3
Add more *-unwind ABI variants
The following *-unwind ABIs are now supported:
- "C-unwind"
- "cdecl-unwind"
- "stdcall-unwind"
- "fastcall-unwind"
- "vectorcall-unwind"
- "thiscall-unwind"
- "aapcs-unwind"
- "win64-unwind"
- "sysv64-unwind"
- "system-unwind"
cc `@rust-lang/wg-ffi-unwind`
Previous efforts to ignore partially consumed values meant we were also
not considering borrows of a projection. This led to cases where we'd
miss borrowed types which MIR expected to be there, leading to ICEs.
Lazy type-alias-impl-trait
Previously opaque types were processed by
1. replacing all mentions of them with inference variables
2. memorizing these inference variables in a side-table
3. at the end of typeck, resolve the inference variables in the side table and use the resolved type as the hidden type of the opaque type
This worked okayish for `impl Trait` in return position, but required lots of roundabout type inference hacks and processing.
This PR instead stops this process of replacing opaque types with inference variables, and just keeps the opaque types around.
Whenever an opaque type `O` is compared with another type `T`, we make the comparison succeed and record `T` as the hidden type. If `O` is compared to `U` while there is a recorded hidden type for it, we grab the recorded type (`T`) and compare that against `U`. This makes implementing
* https://github.com/rust-lang/rfcs/pull/2515
much simpler (previous attempts on the inference based scheme were very prone to ICEs and general misbehaviour that was not explainable except by random implementation defined oddities).
r? `@nikomatsakis`
fixes#93411fixes#88236
Update tracking issue for `const_fn_trait_bound`
It previously pointed to #57563, the conglomerate issue for `const fn` (presumably under the feature gate `const_fn`). This tracking issue doesn't mention anything about `const_fn_trait_bound`(the only occurrence of "trait bound" is for the now-removed `?const Trait` syntax), which can be confusing to people who want to find out more about trait bounds on `const fn`s. This pull request changes the tracking issue to one meant specifically for `const_fn_trait_bound`, #93706, which can help collect information on this feature's stabilization and point users towards `const_trait_impl` if they're looking for const-in-const-contexts trait bounds.
Fixes#93679.
`````@rustbot````` modify labels +A-const-fn +F-const_trait_impl
Suggest 1-tuple parentheses on exprs without existing parens
A follow-on from #86116, split out from #90677.
This alters the suggestion to add a trailing comma to create a 1-tuple - previously we would only apply this if the relevant expression was parenthesised. We now make the suggestion regardless of parentheses, which reduces the fragility of the check (w.r.t formatting).
e.g.
```rust
let a: Option<(i32,)> = Some(3);
```
gets the below suggestion:
```rust
let a: Option<(i32,)> = Some((3,));
// ^ ^^
```
This change also improves the suggestion in other ways, such as by only making the suggestion if the types would match after the suggestion is applied and making the suggestion a multipart suggestion.
This adds in an enum when matching on positions which can either be types or consts.
It will default to emitting old special cased error messages for types.
use `fold_list` in `try_super_fold_with` for `SubstsRef`
split out from #93505 as this by itself is responsible for most of the perf improvements there
r? `@michaelwoerister`
These statistics are computable from the self-profile data and/or ad-hoc
collectable as needed, and in the meantime contribute to rustc bootstrap times.
Fix invalid special casing of the unreachable! macro
This pull-request fix an invalid special casing of the `unreachable!` macro in the same way the `panic!` macro was solved, by adding two new internal only macros `unreachable_2015` and `unreachable_2021` edition dependent and turn `unreachable!` into a built-in macro that do dispatching. This logic is stolen from the `panic!` macro.
~~This pull-request also adds an internal feature `format_args_capture_non_literal` that allows capturing arguments from formatted string that expanded from macros. The original RFC #2795 mentioned this as a future possibility. This feature is [required](https://github.com/rust-lang/rust/issues/92137#issuecomment-1018630522) because of concatenation that needs to be done inside the macro:~~
```rust
$crate::concat!("internal error: entered unreachable code: ", $fmt)
```
**In summary** the new behavior for the `unreachable!` macro with this pr is:
Edition 2021:
```rust
let x = 5;
unreachable!("x is {x}");
```
```
internal error: entered unreachable code: x is 5
```
Edition <= 2018:
```rust
let x = 5;
unreachable!("x is {x}");
```
```
internal error: entered unreachable code: x is {x}
```
Also note that the change in this PR are **insta-stable** and **breaking changes** but this a considered as being a [bug](https://github.com/rust-lang/rust/issues/92137#issuecomment-998441613).
If someone could start a perf run and then a crater run this would be appreciated.
Fixes https://github.com/rust-lang/rust/issues/92137
It previously pointed to #57563, the conglomerate issue for
`const fn` (presumably under the feature gate `const_fn`).
`const_fn_trait_bounds` weren't mentioned here, so this commit changes
its tracking issue to a new one.
Mark the panic_no_unwind lang item as nounwind
This has 2 effects:
- It helps LLVM when inlining since it doesn't need to generate landing pads for `panic_no_unwind`.
- It makes it sound for a panic handler to unwind even if `PanicInfo::can_unwind` returns true. This will simply cause another panic once the unwind tries to go past the `panic_no_unwind` lang item. Eventually this will cause a stack overflow, which is safe.
Require const stability attribute on all stable functions that are `const`
This PR requires all stable functions (of all kinds) that are `const fn` to have a `#[rustc_const_stable]` or `#[rustc_const_unstable]` attribute. Stability was previously implied if omitted; a follow-up PR is planned to change the fallback to be unstable.
