Emit proper errors when on missing closure braces
This commit focuses on emitting clean errors for the following syntax
error:
```
Some(42).map(|a|
dbg!(a);
a
);
```
Previous implementation tried to recover after parsing the closure body
(the `dbg` expression) by replacing the next `;` with a `,`, which made
the next expression belong to the next function argument. As such, the
following errors were emitted (among others):
- the semicolon token was not expected,
- a is not in scope,
- Option::map is supposed to take one argument, not two.
This commit allows us to gracefully handle this situation by adding
giving the parser the ability to remember when it has just parsed a
closure body inside a function call. When this happens, we can treat the
unexpected `;` specifically and try to parse as much statements as
possible in order to eat the whole block. When we can't parse statements
anymore, we generate a clean error indicating that the braces are
missing, and return an ExprKind::Err.
Closes#88065.
r? `@estebank`
Fix stray notes when the source code is not available
Fixes#87060. To reproduce it with a local build of rustc, you have to copy the compiler (e.g. `build/x86_64-unknown-linux-gnu/stage1/`) somewhere and then rename the compiler source directory (maybe there is a smarter way as well). Then, rustc won't find the standard library sources and report stray notes such as
```
note: deref defined here
```
with no location for "here". Another example I've found is this:
```rust
use std::ops::Add;
fn foo<T: Add<Output=()>>(x: T) {
x + x;
}
fn main() {}
```
```
error[E0382]: use of moved value: `x`
--> binop.rs:4:9
|
3 | fn foo<T: Add<Output=()>>(x: T) {
| - move occurs because `x` has type `T`, which does not implement the `Copy` trait
4 | x + x;
| ----^
| | |
| | value used here after move
| `x` moved due to usage in operator
|
note: calling this operator moves the left-hand side
help: consider further restricting this bound
|
3 | fn foo<T: Add<Output=()> + Copy>(x: T) {
| ^^^^^^
error: aborting due to previous error
```
where, again, the note is supposed to point somewhere but doesn't. I have fixed this by checking whether the corresponding source code is actually available before emitting the note.
Add proc_macro::Span::{before, after}.
This adds `proc_macro::Span::before()` and `proc_macro::Span::after()` to get a zero width span at the start or end of the span.
These are equivalent to rustc's `Span::shrink_to_lo()` and `Span::shrink_to_hi()` but with a less cryptic name. They are useful when generating diagnostlics like "missing \<thing\> after \<thing\>".
E.g.
```rust
syn::Error::new(ident.span().after(), "missing `:` after field name").into_compile_error()
```
This commit focuses on emitting clean errors for the following syntax
error:
```
Some(42).map(|a|
dbg!(a);
a
);
```
Previous implementation tried to recover after parsing the closure body
(the `dbg` expression) by replacing the next `;` with a `,`, which made
the next expression belong to the next function argument. As such, the
following errors were emitted (among others):
- the semicolon token was not expected,
- a is not in scope,
- Option::map is supposed to take one argument, not two.
This commit allows us to gracefully handle this situation by adding
giving the parser the ability to remember when it has just parsed a
closure body inside a function call. When this happens, we can treat the
unexpected `;` specifically and try to parse as much statements as
possible in order to eat the whole block. When we can't parse statements
anymore, we generate a clean error indicating that the braces are
missing, and return an ExprKind::Err.
Split rustc_mir
The `rustc_mir` crate is the second largest in the compiler.
This PR splits it up into 5 crates:
- rustc_borrowck;
- rustc_const_eval;
- rustc_mir_dataflow;
- rustc_mir_transform;
- rustc_monomorphize.
Improve diagnostics for unary plus operators (#88276)
This pull request improves the diagnostics emitted on parsing a unary plus operator. See #88276.
Before:
```
error: expected expression, found `+`
--> src/main.rs:2:13
|
2 | let x = +1;
| ^ expected expression
```
After:
```
error: leading `+` is not supported
--> main.rs:2:13
|
2 | let x = +1;
| ^
| |
| unexpected `+`
| help: try removing the `+`
```
Suggest deriving traits if possible
This only applies to builtin derives as I don't think there is a
clean way to get the available derives in typeck.
Closes#85851
Remove `hir::GenericBound::Unsized`
Rather than "moving" the `?Sized` bounds to the param bounds, just also check where clauses in `astconv`. I also did some related cleanup here, but that's not strictly neccesary. Also going to do a perf run here.
r? `@estebank`
Fix handling of +whole-archive native link modifier.
This PR fixes a bug in `add_upstream_native_libraries` that led to the `+whole-archive` modifier being ignored when linking in native libs.
~~Note that the PR does not address the situation when `+whole-archive` is combined with `+bundle`.~~
`@wesleywiser's` commit adds validation code that turns combining `+whole-archive` with `+bundle` into an error.
Fixes https://github.com/rust-lang/rust/issues/88085.
r? `@petrochenkov`
cc `@wesleywiser` `@gcoakes`
Mmap the incremental data instead of reading it.
Instead of reading the full incremental state using `fs::read_file`, we memmap it using a private read-only file-backed map.
This allows the system to reclaim any memory we are not using, while ensuring we are not polluted by
outside modifications to the file.
Suggested in https://github.com/rust-lang/rust/pull/83036#issuecomment-800458082 by `@bjorn3`
Change scope of temporaries in match guards
Each pattern in a match arm has its own copy of the match guard in MIR, with its own temporary, so it has to be dropped before the the guards are joined to the single copy of the arm. This PR changes `then_else_break` to allow it to put the temporary in the innermost scope possible. This change isn't done for `if` expressions because that affects a large number of mir-opt tests and could more significantly affect performance.
closes#88649
r? `@oli-obk`
Remove SmallVector mention
SmallVector is long gone, as it's been first replaced
by OneVector in commit e5e6375352,
which then has been removed entirely in favour of SmallVec in
commit 130a32fa72.
Improve structured tuple struct suggestion
Previously, the span was just for the constructor name, which meant it
would result in syntactically-invalid code when applied. Now, the span
is for the entire expression.
I also changed it to use `span_suggestion_verbose`, for two reasons:
1. Now that the suggestion span has been corrected, the output is a bit
cluttered and hard to read. Putting the suggestion its own window
creates more space.
2. It's easier to see what's being suggested, since now the version
after the suggestion is applied is shown.
r? `@davidtwco`
Avoid invoking the hir_crate query to traverse the HIR
Walking the HIR tree is done using the `hir_crate` query. However, this is unnecessary, since `hir_owner(CRATE_DEF_ID)` provides the same information. Since depending on `hir_crate` forces dependents to always be executed, this leads to unnecessary work.
By splitting HIR and attributes visits, we can avoid an edge to `hir_crate` when trying to visit the HIR tree.
Stop allocating vtable entries for non-object-safe methods
Current a vtable entry is allocated for all associated fns, even if the method is not object-safe: https://godbolt.org/z/h7vx6f35T
As a result, each vtable for `Iterator`' currently consumes 74 `usize`s. This PR stops allocating vtable entries for those methods, reducing vtable size of each `Iterator` vtable to 7 `usize`s.
Note that this PR introduces will cause more invocations of `is_vtable_safe_method`. So a perf run might be needed. If result isn't favorable then we might need to query-ify `is_vtable_safe_method`.
Each pattern in a match arm has its own copy of the match guard in MIR,
with its own temporary, so it has to be dropped before the the guards
are joined to the single copy of the arm.
Provide `layout_of` automatically (given tcx + param_env + error handling).
After #88337, there's no longer any uses of `LayoutOf` within `rustc_target` itself, so I realized I could move the trait to `rustc_middle::ty::layout` and redesign it a bit.
This is similar to #88338 (and supersedes it), but at no ergonomic loss, since there's no funky `C: LayoutOf<Ty = Ty>` -> `Ty: TyAbiInterface<C>` generic `impl` chain, and each `LayoutOf` still corresponds to one `impl` (of `LayoutOfHelpers`) for the specific context.
After this PR, this is what's needed to get `trait LayoutOf` (with the `layout_of` method) implemented on some context type:
* `TyCtxt`, via `HasTyCtxt`
* `ParamEnv`, via `HasParamEnv`
* a way to transform `LayoutError`s into the desired error type
* an error type of `!` can be paired with having `cx.layout_of(...)` return `TyAndLayout` *without* `Result<...>` around it, such as used by codegen
* this is done through a new `LayoutOfHelpers` trait (and so is specifying the type of `cx.layout_of(...)`)
When going through this path (and not bypassing it with a manual `impl` of `LayoutOf`), the end result is that only the error case can be customized, the query itself and the success paths are guaranteed to be uniform.
(**EDIT**: just noticed that because of the supertrait relationship, you cannot actually implement `LayoutOf` yourself, the blanket `impl` fully covers all possible context types that could ever implement it)
Part of the motivation for this shape of API is that I've been working on querifying `FnAbi::of_*`, and what I want/need to introduce for that looks a lot like the setup in this PR - in particular, it's harder to express the `FnAbi` methods in `rustc_target`, since they're much more tied to `rustc` concepts.
r? `@nagisa` cc `@oli-obk` `@bjorn3`
Fix 2021 `dyn` suggestion that used code as label
The arguments to `span_suggestion` were in the wrong order, so the error
looked like this:
error[E0783]: trait objects without an explicit `dyn` are deprecated
--> src/test/ui/editions/dyn-trait-sugg-2021.rs:10:5
|
10 | Foo::hi(123);
| ^^^ help: <dyn Foo>: `use `dyn``
Now the error looks like this, as expected:
error[E0783]: trait objects without an explicit `dyn` are deprecated
--> src/test/ui/editions/dyn-trait-sugg-2021.rs:10:5
|
10 | Foo::hi(123);
| ^^^ help: use `dyn`: `<dyn Foo>`
This issue was only present in the 2021 error; the 2018 lint was
correct.
r? `@m-ou-se`
SmallVector is long gone, as it's been first replaced
by OneVector in commit e5e6375352,
which then has been removed entirely in favour of SmallVec in
commit 130a32fa72.
