Remove `token::{Open,Close}Delim`
By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.
PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.
This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
`Delimiter` values to `TokenKind`.
Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
- } else if self.token != token::CloseDelim(Delimiter::Brace) {
+ } else if self.token != token::CloseBrace {
```
r? `@petrochenkov`
By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.
PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.
This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
`Delimiter` values to `TokenKind`.
Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
- } else if self.token != token::CloseDelim(Delimiter::Brace) {
+ } else if self.token != token::CloseBrace {
```
Autodiff batching2
~I will rebase it once my first PR landed.~ done.
This autodiff batch mode is more similar to scalar autodiff, since it still only takes one shadow argument.
However, that argument is supposed to be `width` times larger.
r? `@oli-obk`
Tracking:
- https://github.com/rust-lang/rust/issues/124509
I'm removing empty identifiers everywhere, because in practice they
always mean "no identifier" rather than "empty identifier". (An empty
identifier is impossible.) It's better to use `Option` to mean "no
identifier" because you then can't forget about the "no identifier"
possibility.
Some specifics:
- When testing an attribute for a single name, the commit uses the
`has_name` method.
- When testing an attribute for multiple names, the commit uses the new
`has_any_name` method.
- When using `match` on an attribute, the match arms now have `Some` on
them.
In the tests, we now avoid printing empty identifiers by not printing
the identifier in the `error:` line at all, instead letting the carets
point out the problem.
Detect and provide suggestion for `&raw EXPR`
When emitting an error in the parser, and we detect that the previous token was `raw` and we *could* have consumed `const`/`mut`, suggest that this may have been a mistyped raw ref expr. To do this, we add `const`/`mut` to the expected token set when parsing `&raw` as an expression (which does not affect the "good path" of parsing, for the record).
This is kind of a rudimentary error improvement, since it doesn't actually attempt to recover anything, leading to some other knock-on errors b/c we still treat `&raw` as the expression that was parsed... but at least we add the suggestion! I don't think the parser grammar means we can faithfully recover `&raw EXPR` early, i.e. during `parse_expr_borrow`.
Fixes#133231
Rollup of 9 pull requests
Successful merges:
- #138336 (Improve `-Z crate-attr` diagnostics)
- #139636 (Encode dep node edge count as u32 instead of usize)
- #139666 (cleanup `mir_borrowck`)
- #139695 (compiletest: consistently use `camino::{Utf8Path,Utf8PathBuf}` throughout)
- #139699 (Proactively update coroutine drop shim's phase to account for later passes applied during shim query)
- #139718 (enforce unsafe attributes in pre-2024 editions by default)
- #139722 (Move some things to rustc_type_ir)
- #139760 (UI tests: migrate remaining compile time `error-pattern`s to line annotations when possible)
- #139776 (Switch attrs to `diagnostic::on_unimplemented`)
r? `@ghost`
`@rustbot` modify labels: rollup
- Show the `#![ ... ]` in the span (to make it clear that it should not
be included in the CLI argument)
- Show more detailed errors when the crate has valid token trees but
invalid syntax.
Previously, `crate-attr=feature(foo),feature(bar)` would just say
"invalid crate attribute" and point at the comma. Now, it explicitly
says that the comma was unexpected, which is useful when using
`--error-format=short`. It also fixes the column to show the correct
span.
- Recover from parse errors. Previously we would abort immediately on
syntax errors; now we go on to try and type-check the rest of the
crate.
The new diagnostic code also happens to be slightly shorter.
It bugs me when variables of type `Ident` are called `name`. It leads to
silly things like `name.name`. `Ident` variables should be called
`ident`, and `name` should be used for variables of type `Symbol`.
This commit improves things by by doing `s/name/ident/` on a bunch of
`Ident` variables. Not all of them, but a decent chunk.
add sret handling for scalar autodiff
r? `@oli-obk`
Fixing one of the todo's which I left in my previous batching PR.
This one handles sret for scalar autodiff. `sret` mostly shows up when we try to return a lot of scalar floats.
People often start testing autodiff which toy functions which just use a few scalars as inputs and outputs, and those were the most likely to be affected by this issue. So this fix should make learning/teaching hopefully a bit easier.
Tracking:
- https://github.com/rust-lang/rust/issues/124509
Implement `super let`
Tracking issue: https://github.com/rust-lang/rust/issues/139076
This implements `super let` as proposed in #139080, based on the following two equivalence rules.
1. For all expressions `$expr` in any context, these are equivalent:
- `& $expr`
- `{ super let a = & $expr; a }`
2. And, additionally, these are equivalent in any context when `$expr` is a temporary (aka rvalue):
- `& $expr`
- `{ super let a = $expr; & a }`
So far, this experiment has a few interesting results:
## Interesting result 1
In this snippet:
```rust
super let a = f(&temp());
```
I originally expected temporary `temp()` would be dropped at the end of the statement (`;`), just like in a regular `let`, because `temp()` is not subject to temporary lifetime extension.
However, it turns out that that would break the fundamental equivalence rules.
For example, in
```rust
g(&f(&temp()));
```
the temporary `temp()` will be dropped at the `;`.
The first equivalence rule tells us this must be equivalent:
```rust
g({ super let a = &f(&temp()); a });
```
But that means that `temp()` must live until the last `;` (after `g()`), not just the first `;` (after `f()`).
While this was somewhat surprising to me at first, it does match the exact behavior we need for `pin!()`: The following _should work_. (See also https://github.com/rust-lang/rust/issues/138718)
```rust
g(pin!(f(&mut temp())));
```
Here, `temp()` lives until the end of the statement. This makes sense from the perspective of the user, as no other `;` or `{}` are visible. Whether `pin!()` uses a `{}` block internally or not should be irrelevant.
This means that _nothing_ in a `super let` statement will be dropped at the end of that super let statement. It does not even need its own scope.
This raises questions that are useful for later on:
- Will this make temporaries live _too long_ in cases where `super let` is used not in a hidden block in a macro, but as a visible statement in code like the following?
```rust
let writer = {
super let file = File::create(&format!("/home/{user}/test"));
Writer::new(&file)
};
```
- Is a `let` statement in a block still the right syntax for this? Considering it has _no_ scope of its own, maybe neither a block nor a statement should be involved
This leads me to think that instead of `{ super let $pat = $init; $expr }`, we might want to consider something like `let $pat = $init in $expr` or `$expr where $pat = $init`. Although there are also issues with these, as it isn't obvious anymore if `$init` should be subject to temporary lifetime extension. (Do we want both `let _ = _ in ..` and `super let _ = _ in ..`?)
## Interesting result 2
What about `super let x;` without initializer?
```rust
let a = {
super let x;
x = temp();
&x
};
```
This works fine with the implementation in this PR: `x` is extended to live as long as `a`.
While it matches my expectations, a somewhat interesting thing to realize is that these are _not_ equivalent:
- `super let x = $expr;`
- `super let x; x = $expr;`
In the first case, all temporaries in $expr will live at least as long as (the result of) the surrounding block.
In the second case, temporaries will be dropped at the end of the assignment statement. (Because the assignment statement itself "is not `super`".)
This difference in behavior might be confusing, but it _might_ be useful.
One might want to extend the lifetime of a variable without extending all the temporaries in the initializer expression.
On the other hand, that can also be expressed as:
- `let x = $expr; super let x = x;` (w/o temporary lifetime extension), or
- `super let x = { $expr };` (w/ temporary lifetime extension)
So, this raises these questions:
- Do we want to accept `super let x;` without initializer at all?
- Does it make sense for statements other than let statements to be "super"? An expression statement also drops temporaries at its `;`, so now that we discovered that `super let` basically disables that `;` (see interesting result 1), is there a use to having other statements without their own scope? (I don't think that's ever useful?)
## Interesting result 3
This works now:
```rust
super let Some(x) = a.get(i) else { return };
```
I didn't put in any special cases for `super let else`. This is just the behavior that 'naturally' falls out when implementing `super let` without thinking of the `let else` case.
- Should `super let else` work?
## Interesting result 4
This 'works':
```rust
fn main() {
super let a = 123;
}
```
I didn't put in any special cases for `super let` at function scope. I had expected the code to cause an ICE or other weird failure when used at function body scope, because there's no way to let the variable live as long as the result of the function.
This raises the question:
- Does this mean that this behavior is the natural/expected behavior when `super let` is used at function scope? Or is this just a quirk and should we explicitly disallow `super let` in a function body? (Probably the latter.)
---
The questions above do not need an answer to land this PR. These questions should be considered when redesigning/rfc'ing/stabilizing the feature.
Add new `PatKind::Missing` variants
To avoid some ugly uses of `kw::Empty` when handling "missing" patterns, e.g. in bare fn tys. Helps with #137978. Details in the individual commits.
r? ``@oli-obk``
Add `*_value` methods to proc_macro lib
This is the (re-)implementation of https://github.com/rust-lang/libs-team/issues/459.
It allows to get the actual value (unescaped) of the different string literals.
It was originally done in https://github.com/rust-lang/rust/pull/136355 but it broke the artifacts build so we decided to move the crate to crates.io to go around this limitation.
Part of https://github.com/rust-lang/rust/issues/136652.
Considering this is a copy-paste of the originally approved PR, no need to go through the whole process again. \o/
r? `@Urgau`
Autodiff batching
Enzyme supports batching, which is especially known from the ML side when training neural networks.
There we would normally have a training loop, where in each iteration we would pass in some data (e.g. an image), and a target vector. Based on how close we are with our prediction we compute our loss, and then use backpropagation to compute the gradients and update our weights.
That's quite inefficient, so what you normally do is passing in a batch of 8/16/.. images and targets, and compute the gradients for those all at once, allowing better optimizations.
Enzyme supports batching in two ways, the first one (which I implemented here) just accepts a Batch size,
and then each Dual/Duplicated argument has not one, but N shadow arguments. So instead of
```rs
for i in 0..100 {
df(x[i], y[i], 1234);
}
```
You can now do
```rs
for i in 0..100.step_by(4) {
df(x[i+0],x[i+1],x[i+2],x[i+3], y[i+0], y[i+1], y[i+2], y[i+3], 1234);
}
```
which will give the same results, but allows better compiler optimizations. See the testcase for details.
There is a second variant, where we can mark certain arguments and instead of having to pass in N shadow arguments, Enzyme assumes that the argument is N times longer. I.e. instead of accepting 4 slices with 12 floats each, we would accept one slice with 48 floats. I'll implement this over the next days.
I will also add more tests for both modes.
For any one preferring some more interactive explanation, here's a video of Tim's llvm dev talk, where he presents his work. https://www.youtube.com/watch?v=edvaLAL5RqU
I'll also add some other docs to the dev guide and user docs in another PR.
r? ghost
Tracking:
- https://github.com/rust-lang/rust/issues/124509
- https://github.com/rust-lang/rust/issues/135283
In the AST, currently we use `BinOpKind` within `ExprKind::AssignOp` and
`AssocOp::AssignOp`, even though this allows some nonsensical
combinations. E.g. there is no `&&=` operator. Likewise for HIR and
THIR.
This commit introduces `AssignOpKind` which only includes the ten
assignable operators, and uses it in `ExprKind::AssignOp` and
`AssocOp::AssignOp`. (And does similar things for `hir::ExprKind` and
`thir::ExprKind`.) This avoids the possibility of nonsensical
combinations, as seen by the removal of the `bug!` case in
`lang_item_for_binop`.
The commit is mostly plumbing, including:
- Adds an `impl From<AssignOpKind> for BinOpKind` (AST) and `impl
From<AssignOp> for BinOp` (MIR/THIR).
- `BinOpCategory` can now be created from both `BinOpKind` and
`AssignOpKind`.
- Replaces the `IsAssign` type with `Op`, which has more information and
a few methods.
- `suggest_swapping_lhs_and_rhs`: moves the condition to the call site,
it's easier that way.
- `check_expr_inner`: had to factor out some code into a separate
method.
I'm on the fence about whether avoiding the nonsensical combinations is
worth the extra code.
They are no longer needed.
This does slightly worsen the error message for a single test, but that
test contains code that is so badly broken that I'm not worried about
it.
Notes about tests:
- tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs: some messages are
now duplicated due to repeated parsing.
- tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs: ditto.
- `tests/ui/proc-macro/macro-rules-derive-cfg.rs`: the diff looks large
but the only difference is the insertion of a single
invisible-delimited group around a metavar.
- `tests/ui/attributes/nonterminal-expansion.rs`: a slight span
degradation, somehow related to the recent massive attr parsing
rewrite (#135726). I couldn't work out exactly what is going wrong,
but I don't think it's worth holding things up for a single slightly
suboptimal error message.
`ast::Item` has an `ident` field.
- It's always non-empty for these item kinds: `ExternCrate`, `Static`,
`Const`, `Fn`, `Mod`, `TyAlias`, `Enum`, `Struct`, `Union`,
`Trait`, `TraitAlias`, `MacroDef`, `Delegation`.
- It's always empty for these item kinds: `Use`, `ForeignMod`,
`GlobalAsm`, `Impl`, `MacCall`, `DelegationMac`.
There is a similar story for `AssocItemKind` and `ForeignItemKind`.
Some sites that handle items check for an empty ident, some don't. This
is a very C-like way of doing things, but this is Rust, we have sum
types, we can do this properly and never forget to check for the
exceptional case and never YOLO possibly empty identifiers (or possibly
dummy spans) around and hope that things will work out.
The commit is large but it's mostly obvious plumbing work. Some notable
things.
- `ast::Item` got 8 bytes bigger. This could be avoided by boxing the
fields within some of the `ast::ItemKind` variants (specifically:
`Struct`, `Union`, `Enum`). I might do that in a follow-up; this
commit is big enough already.
- For the visitors: `FnKind` no longer needs an `ident` field because
the `Fn` within how has one.
- In the parser, the `ItemInfo` typedef is no longer needed. It was used
in various places to return an `Ident` alongside an `ItemKind`, but
now the `Ident` (if present) is within the `ItemKind`.
- In a few places I renamed identifier variables called `name` (or
`foo_name`) as `ident` (or `foo_ident`), to better match the type, and
because `name` is normally used for `Symbol`s. It's confusing to see
something like `foo_name.name`.
"Missing" patterns are possible in bare fn types (`fn f(u32)`) and
similar places. Currently these are represented in the AST with
`ast::PatKind::Ident` with no `by_ref`, no `mut`, an empty ident, and no
sub-pattern. This flows through to `{hir,thir}::PatKind::Binding` for
HIR and THIR.
This is a bit nasty. It's very non-obvious, and easy to forget to check
for the exceptional empty identifier case.
This commit adds a new variant, `PatKind::Missing`, to do it properly.
The process I followed:
- Add a `Missing` variant to `{ast,hir,thir}::PatKind`.
- Chang `parse_param_general` to produce `ast::PatKind::Missing`
instead of `ast::PatKind::Missing`.
- Look through `kw::Empty` occurrences to find functions where an
existing empty ident check needs replacing with a `PatKind::Missing`
check: `print_param`, `check_trait_item`, `is_named_param`.
- Add a `PatKind::Missing => unreachable!(),` arm to every exhaustive
match identified by the compiler.
- Find which arms are actually reachable by running the test suite,
changing them to something appropriate, usually by looking at what
would happen to a `PatKind::Ident`/`PatKind::Binding` with no ref, no
`mut`, an empty ident, and no subpattern.
Quite a few of the `unreachable!()` arms were never reached. This makes
sense because `PatKind::Missing` can't happen in every pattern, only
in places like bare fn tys and trait fn decls.
I also tried an alternative approach: modifying `ast::Param::pat` to
hold an `Option<P<Pat>>` instead of a `P<Pat>`, but that quickly turned
into a very large and painful change. Adding `PatKind::Missing` is much
easier.
Mostly parser: Eliminate code that's been dead / semi-dead since the removal of type ascription syntax
**Disclaimer**: This PR is intended to mostly clean up code as opposed to bringing about behavioral changes. Therefore it doesn't aim to address any of the 'FIXME: remove after a month [dated: 2023-05-02]: "type ascription syntax has been removed, see issue [#]101728"'.
---
By commit:
1. Removes truly dead code:
* Since 1.71 (#109128) `let _ = { f: x };` is a syntax error as opposed to a semantic error which allows the parse-time diagnostic (suggestion) "*struct literal body without path // you might have forgotten […]*" to kick in.
* The analysis-time diagnostic (suggestion) from <=1.70 "*cannot find value \`f\` in this scope // you might have forgotten […]*" is therefore no longer reachable.
2. Updates `is_certainly_not_a_block` to be in line with the current grammar:
* The seq. `{ ident:` is definitely not the start of a block. Before the removal of ty ascr, `{ ident: ty_start` would begin a block expr.
* This shouldn't make more code compile IINM, it should *ultimately* only affect diagnostics.
* For example, `if T { f: () } {}` will now be interpreted as an `if` with struct lit `T { f: () }` as its *condition* (which is banned in the parser anyway) as opposed to just `T` (with the *consequent* being `f : ()` which is also invalid (since 1.71)). The diagnostics are almost the same because we have two separate parse recovery procedures + diagnostics: `StructLiteralNeedingParens` (*invalid struct lit*) before and `StructLiteralNotAllowedHere` (*struct lits aren't allowed here*) now, as you can see from the diff.
* (As an aside, even before this PR, fn `maybe_suggest_struct_literal` should've just used the much older & clearer `StructLiteralNotAllowedHere`)
* NB: This does sadly regress the compiler output for `tests/ui/parser/type-ascription-in-pattern.rs` but that can be fixed in follow-up PRs. It's not super important IMO and a natural consequence.
3. Removes code that's become dead due to the prior commit.
* Basically reverts #106620 + #112475 (without regressing rustc's output!).
* Now the older & more robust parse recovery procedure (cc `StructLiteralNotAllowedHere`) takes care of the cases the removed code used to handle.
* This automatically fixes the suggestions for \[[playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=7e2030163b11ee96d17adc3325b01780)\]:
* `if Ty::<i32> { f: K }.m() {}`: `if Ty::<i32> { SomeStruct { f: K } }.m() {}` (broken) → ` if (Ty::<i32> { f: K }).m() {}`
* `if <T as Trait>::Out { f: K::<> }.m() {}`: `if <T as Trait>(::Out { f: K::<> }).m() {}` (broken) → `if (<T as Trait>::Out { f: K::<> }).m() {}`
4. Merge and simplify UI tests pertaining to this issue, so it's easier to add more regression tests like for the two cases mentioned above.
5. Merge UI tests and add the two regression tests.
Best reviewed commit by commit (on request I'll partially squash after approval).
Visitors track whether an assoc item is in a trait impl or an inherent impl
`AssocCtxt::Impl` now contains an `of_trait` field. This allows ast lowering and nameres to not have to track whether we're in a trait impl or an inherent impl.
They're dodgy, covering all the keywords, including weak ones, and
edition-specific ones without considering the edition. They have a
single use in rustfmt. This commit changes that use to
`is_reserved_ident`, which is a much more widely used alternative and is
good enough, judging by the lack of effect on the test suite.
Handle spans of `~const`, `const` and `async` trait bounds in macro expansion
r? `@compiler-errors`
`visit_span` is actually only used in one place (the `transcribe::Marker`), and all of this syntax is unstable, so while it would still be nice to write a test for it, I wager there's lots more interesting things in `transcribe::Marker` to write tests for. And the worst is some diagnostics being weird or incremental being not as incremental as it could be
