It currently has two, which don't accurately capture what's happening --
the `TupleStruct` spans are allocated in `ResolverArenas`, which is
different to where the `Expr` is allocated -- and require some
"outlives" constraints to be used.
This commit adds another lifetime, renames the existing ones, and
removes the "outlives" constraints.
Improve diagnostics for usage of qualified paths within tuple struct exprs/pats
For patterns the old diagnostic was just incorrect, but I also added machine applicable suggestions.
For context, this special cases errors for `<T as Trait>::Assoc(..)` patterns and expressions (latter is just a call). Tuple struct patterns and expressions both live in the value namespace, so they are not forwarded through associated *types*.
r? ``@jdonszelmann``
cc ``@petrochenkov`` in https://github.com/rust-lang/rust/pull/80080#issuecomment-800630582 you were wondering why it doesn't work for types, that's why — tuple patterns are resolved in the value namespace.
Suggest use "{}", self.x instead of {self.x} when resolve x as field of `self`
Fixes#141136
Changes can be seen in the second commit: 9de7fff0d8
r? compiler
To accurately reflect that RPITIT assoc items don't have a name. This
avoids the use of `kw::Empty` to mean "no name", which is error prone.
Helps with #137978.
`hir::AssocItem` currently has a boolean `fn_has_self_parameter` field,
which is misplaced, because it's only relevant for associated fns, not
for associated consts or types. This commit moves it (and renames it) to
the `AssocKind::Fn` variant, where it belongs.
This requires introducing a new C-style enum, `AssocTag`, which is like
`AssocKind` but without the fields. This is because `AssocKind` values
are passed to various functions like `find_by_ident_and_kind` to
indicate what kind of associated item should be searched for, and having
to specify `has_self` isn't relevant there.
New methods:
- Predicates `AssocItem::is_fn` and `AssocItem::is_method`.
- `AssocItem::as_tag` which converts `AssocItem::kind` to `AssocTag`.
Removed `find_by_name_and_kinds`, which is unused.
`AssocItem::descr` can now distinguish between methods and associated
functions, which slightly improves some error messages.
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.
`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`.
Improve suggest construct with literal syntax instead of calling
Closing #138931
When constructing a structure through a format similar to calling a constructor, we can use verbose suggestions to hint at using literal syntax for clearer advice. The case of multiple fields is also considered here, provided that the field has the same number of arguments as CallExpr.
r? compiler
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).
Parameter patterns are lowered to an `Ident` by
`lower_fn_params_to_names`, which is used when lowering bare function
types, trait methods, and foreign functions. Currently, there are two
exceptional cases where the lowered param can become an empty `Ident`.
- If the incoming pattern is an empty `Ident`. This occurs if the
parameter is anonymous, e.g. in a bare function type.
- If the incoming pattern is neither an ident nor an underscore. Any
such parameter will have triggered a compile error (hence the
`span_delayed_bug`), but lowering still occurs.
This commit replaces these empty `Ident` results with `None`, which
eliminates a number of `kw::Empty` uses, and makes it impossible to fail
to check for these exceptional cases.
Note: the `FIXME` comment in `is_unwrap_or_empty_symbol` is removed. It
actually should have been removed in #138482, the precursor to this PR.
That PR changed the lowering of wild patterns to `_` symbols instead of
empty symbols, which made the mentioned underscore check load-bearing.
Provide more context on resolve error caused from incorrect RTN
When encountering a resolve E0575 error for an associated method (when a type was expected), see if it could have been an intended return type notation bound.
```
error[E0575]: expected associated type, found associated function `Trait::method`
--> $DIR/bad-inputs-and-output.rs:31:36
|
LL | fn foo_qualified<T: Trait>() where <T as Trait>::method(i32): Send {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^ not a associated type
|
help: you might have meant to use the return type notation syntax
|
LL - fn foo_qualified<T: Trait>() where <T as Trait>::method(i32): Send {}
LL + fn foo_qualified<T: Trait>() where T::method(..): Send {}
|
```
Built on top of #137824, only second commit is relevant for review.
r? ````````@compiler-errors````````
Try to point of macro expansion from resolver and method errors if it involves macro var
In the case that a macro caller passes an identifier into a macro generating a path or method expression, point out that identifier in the context of the *macro* so it's a bit more clear how the macro is involved in causing the error.
r? ``````````@estebank`````````` or reassign
When encountering a resolve E0575 error for an associated method (when a type was expected), see if it could have been an intended return type notation bound.
```
error[E0575]: expected associated type, found associated function `Trait::method`
--> $DIR/bad-inputs-and-output.rs:31:36
|
LL | fn foo_qualified<T: Trait>() where <T as Trait>::method(i32): Send {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^ not a associated type
|
help: you might have meant to use the return type notation syntax
|
LL - fn foo_qualified<T: Trait>() where <T as Trait>::method(i32): Send {}
LL + fn foo_qualified<T: Trait>() where T::method(..): Send {}
|
```
Suggest replacing `.` with `::` when encountering "expected value, found enum":
- in a method-call expression and the method has the same name as a tuple variant
- in a field-access expression and the field has the same name as a unit or tuple variant
When `Foo.field` or `Foo.method()` exprs are encountered, suggest `Foo::field` or `Foo::method()` when Foo is a type alias, not just
a struct, trait, or module.
Also rename test for this suggestion from issue-22692.rs to something more meaningful.
Re-export more `rustc_span::symbol` things from `rustc_span`.
`rustc_span::symbol` defines some things that are re-exported from `rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some closely related things such as `Ident` and `kw`. So you can do `use rustc_span::{Symbol, sym}` but you have to do `use rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`, and changes many `rustc_span::symbol::` qualifiers to `rustc_span::`. This is a 300+ net line of code reduction, mostly because many files with two `use rustc_span` items can be reduced to one.
r? `@jieyouxu`
`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.
