By using `token_descr`, as is done for many other errors, we can get
slightly better descriptions in error messages, e.g.
"macro expansion ignores token `let` and any following" becomes
"macro expansion ignores keyword `let` and any tokens following".
This will be more important once invisible delimiters start being
mentioned in error messages -- without this commit, that leads to error
messages such as "error at ``" because invisible delimiters are
pretty printed as an empty string.
Add suggestion for removing invalid path sep `::` in fn def
Add suggestion for removing invalid path separator `::` in function definition.
for example: `fn invalid_path_separator::<T>() {}`
fixes#130791
```
error: expected a pattern, found an expression
--> f889.rs:3:13
|
3 | let (x, y.drop()) = (1, 2); //~ ERROR
| ^^^^^^^^ not a pattern
|
= note: arbitrary expressions are not allowed in patterns: <https://doc.rust-lang.org/book/ch18-00-patterns.html>
error[E0532]: expected a pattern, found a function call
--> f889.rs:2:13
|
2 | let (x, drop(y)) = (1, 2); //~ ERROR
| ^^^^ not a tuple struct or tuple variant
|
= note: function calls are not allowed in patterns: <https://doc.rust-lang.org/book/ch18-00-patterns.html>
```
Fix#97200.
rustc_expand: remember module `#[path]`s during expansion
During invocation collection, if a module item parsed from a `#[path]` attribute needed a second pass after parsing, its path wouldn't get added to the file path stack, so cycle detection broke. This checks the `#[path]` in such cases, so that it gets added appropriately. I think it should work identically to the case for external modules that don't need a second pass, but I'm not 100% sure.
Fixes#97589
Implement a Method to Seal `DiagInner`'s Suggestions
This PR adds a method on `DiagInner` called `.seal_suggestions()` to prevent new suggestions from being added while preserving existing suggestions.
This is useful because currently there is no way to prevent new suggestions from being added to a diagnostic. `.disable_suggestions()` is the closest but it gets rid of all suggestions before and after the call.
Therefore, `.seal_suggestions()` can be used when, for example, misspelled keyword is detected and reported. In such cases, we may want to prevent other suggestions from being added to the diagnostic, as they would likely be meaningless once the misspelled keyword is identified. For context: https://github.com/rust-lang/rust/pull/129899#discussion_r1741307132
To store an additional state, the type of the `suggestions` field in `DiagInner` was changed into a three variant enum. While this change affects files across different crates, care was taken to preserve the existing code's semantics. This is validated by the fact that all UI tests pass without any modifications.
r? chenyukang
Suggest the correct pattern syntax on usage of unit variant pattern for a struct variant
Closes#126243
I add a suggestion on usage of unit variant pattern for a struct variant.
This PR detects misspelled keywords using two heuristics:
1. Lowercasing the unexpected identifier.
2. Using edit distance to find a keyword similar to the unexpected identifier.
However, it does not detect each and every misspelled keyword to
minimize false positives and ambiguities. More details about the
implementation can be found in the comments.
For codepoint boundary assertion triggered by a let stmt compound
assignment removal suggestion when encountering recovered multi-byte
compound ops.
Issue: <https://github.com/rust-lang/rust/issues/128845>
Add limit for unclosed delimiters in lexer diagnostic
Fixes#127868
The first commit shows the original diagnostic, and the second commit shows the changes.
Improve `extern "<abi>" unsafe fn()` error message
These errors were already reported in #87217, and fixed by #87235 but missed the case of an explicit ABI.
This PR does not cover multiple keywords like `extern "C" pub const unsafe fn()`, but I don't know what a good way to cover this would be. It also seems rarer than `extern "C" unsafe` which I saw happen a few times in workshops.
Replace ASCII control chars with Unicode Control Pictures
Replace ASCII control chars like `CR` with Unicode Control Pictures like `␍`:
```
error: bare CR not allowed in doc-comment
--> $DIR/lex-bare-cr-string-literal-doc-comment.rs:3:32
|
LL | /// doc comment with bare CR: '␍'
| ^
```
Centralize the checking of unicode char width for the purposes of CLI display in one place. Account for the new replacements. Remove unneeded tracking of "zero-width" unicode chars, as we calculate these in the `SourceMap` as needed now.
Reorder trait bound modifiers *after* `for<...>` binder in trait bounds
This PR suggests changing the grammar of trait bounds from:
```
[CONSTNESS] [ASYNCNESS] [?] [BINDER] [TRAIT_PATH]
const async ? for<'a> Sized
```
to
```
([BINDER] [CONSTNESS] [ASYNCNESS] | [?]) [TRAIT_PATH]
```
i.e., either
```
? Sized
```
or
```
for<'a> const async Sized
```
(but not both)
### Why?
I think it's strange that the binder applies "more tightly" than the `?` trait polarity. This becomes even weirder when considering that we (or at least, I) want to have `async` trait bounds expressed like:
```
where T: for<'a> async Fn(&'a ()) -> i32,
```
and not:
```
where T: async for<'a> Fn(&'a ()) -> i32,
```
### Fallout
No crates on crater use this syntax, presumably because it's literally useless. This will require modifying the reference grammar, though.
### Alternatives
If this is not desirable, then we can alternatively keep parsing `for<'a>` after the `?` but deprecate it with either an FCW (or an immediate hard error), and begin parsing `for<'a>` *before* the `?`.
We are moving toward forbidding `missing_fragment_specifier` either in
edition 2024 or unconditionally. Make a first step toward this by
ensuring crates that rely on the old behavior are reported when used as
dependencies.
Tracking issue: <https://github.com/rust-lang/rust/issues/128143>
Tweak suggestions when using incorrect type of enum literal
More accurate suggestions when writing wrong style of enum variant literal:
```
error[E0533]: expected value, found struct variant `E::Empty3`
--> $DIR/empty-struct-braces-expr.rs:18:14
|
LL | let e3 = E::Empty3;
| ^^^^^^^^^ not a value
|
help: you might have meant to create a new value of the struct
|
LL | let e3 = E::Empty3 {};
| ++
```
```
error[E0533]: expected value, found struct variant `E::V`
--> $DIR/struct-literal-variant-in-if.rs:10:13
|
LL | if x == E::V { field } {}
| ^^^^ not a value
|
help: you might have meant to create a new value of the struct
|
LL | if x == (E::V { field }) {}
| + +
```
```
error[E0618]: expected function, found enum variant `Enum::Unit`
--> $DIR/suggestion-highlights.rs:15:5
|
LL | Unit,
| ---- enum variant `Enum::Unit` defined here
...
LL | Enum::Unit();
| ^^^^^^^^^^--
| |
| call expression requires function
|
help: `Enum::Unit` is a unit enum variant, and does not take parentheses to be constructed
|
LL - Enum::Unit();
LL + Enum::Unit;
|
```
```
error[E0599]: no variant or associated item named `tuple` found for enum `Enum` in the current scope
--> $DIR/suggestion-highlights.rs:36:11
|
LL | enum Enum {
| --------- variant or associated item `tuple` not found for this enum
...
LL | Enum::tuple;
| ^^^^^ variant or associated item not found in `Enum`
|
help: there is a variant with a similar name
|
LL | Enum::Tuple(/* i32 */);
| ~~~~~~~~~~~~~~~~;
|
```
Tweak "field not found" suggestion when giving struct literal for tuple struct type:
```
error[E0560]: struct `S` has no field named `x`
--> $DIR/nested-non-tuple-tuple-struct.rs:8:19
|
LL | pub struct S(f32, f32);
| - `S` defined here
...
LL | let _x = (S { x: 1.0, y: 2.0 }, S { x: 3.0, y: 4.0 });
| ^ field does not exist
|
help: `S` is a tuple struct, use the appropriate syntax
|
LL | let _x = (S(/* f32 */, /* f32 */), S { x: 3.0, y: 4.0 });
| ~~~~~~~~~~~~~~~~~~~~~~~
We already point these out quite aggressively, telling people not to use them, but would normally be rendered as nothing. Having them visible will make it easier for people to actually deal with them.
```
error: unicode codepoint changing visible direction of text present in literal
--> $DIR/unicode-control-codepoints.rs:26:22
|
LL | println!("{:?}", '�');
| ^-^
| ||
| |'\u{202e}'
| this literal contains an invisible unicode text flow control codepoint
|
= note: these kind of unicode codepoints change the way text flows on applications that support them, but can cause confusion because they change the order of characters on the screen
= help: if their presence wasn't intentional, you can remove them
help: if you want to keep them but make them visible in your source code, you can escape them
|
LL | println!("{:?}", '\u{202e}');
| ~~~~~~~~
```
vs the previous
```
error: unicode codepoint changing visible direction of text present in literal
--> $DIR/unicode-control-codepoints.rs:26:22
|
LL | println!("{:?}", '');
| ^-
| ||
| |'\u{202e}'
| this literal contains an invisible unicode text flow control codepoint
|
= note: these kind of unicode codepoints change the way text flows on applications that support them, but can cause confusion because they change the order of characters on the screen
= help: if their presence wasn't intentional, you can remove them
help: if you want to keep them but make them visible in your source code, you can escape them
|
LL | println!("{:?}", '\u{202e}');
| ~~~~~~~~
```
No longer track "zero-width" chars in `SourceMap`, read directly from the line when calculating the `display_col` of a `BytePos`. Move `char_width` to `rustc_span` and use it from the emitter.
This change allows the following to properly align in terminals (depending on the font, the replaced control codepoints are rendered as 1 or 2 width, on my terminal they are rendered as 1, on VSCode text they are rendered as 2):
```
error: this file contains an unclosed delimiter
--> $DIR/issue-68629.rs:5:17
|
LL | ␜␟ts␀![{i
| -- unclosed delimiter
| |
| unclosed delimiter
LL | ␀␀ fn rݻoa>rݻm
| ^
```
```
error[E0533]: expected value, found struct variant `E::Empty3`
--> $DIR/empty-struct-braces-expr.rs:18:14
|
LL | let e3 = E::Empty3;
| ^^^^^^^^^ not a value
|
help: you might have meant to create a new value of the struct
|
LL | let e3 = E::Empty3 {};
| ++
```
```
error[E0533]: expected value, found struct variant `E::V`
--> $DIR/struct-literal-variant-in-if.rs:10:13
|
LL | if x == E::V { field } {}
| ^^^^ not a value
|
help: you might have meant to create a new value of the struct
|
LL | if x == (E::V { field }) {}
| + +
```
```
error[E0618]: expected function, found enum variant `Enum::Unit`
--> $DIR/suggestion-highlights.rs:15:5
|
LL | Unit,
| ---- enum variant `Enum::Unit` defined here
...
LL | Enum::Unit();
| ^^^^^^^^^^--
| |
| call expression requires function
|
help: `Enum::Unit` is a unit enum variant, and does not take parentheses to be constructed
|
LL - Enum::Unit();
LL + Enum::Unit;
|
```
```
error[E0599]: no variant or associated item named `tuple` found for enum `Enum` in the current scope
--> $DIR/suggestion-highlights.rs:36:11
|
LL | enum Enum {
| --------- variant or associated item `tuple` not found for this enum
...
LL | Enum::tuple;
| ^^^^^ variant or associated item not found in `Enum`
|
help: there is a variant with a similar name
|
LL | Enum::Tuple(/* i32 */);
| ~~~~~~~~~~~~~~~~;
|
```
The second suggestion shown here would previously incorrectly assume that the span corresponding to `⩵` was 2 bytes wide composed by 2 1 byte wide chars, so a span pointing at `==` could point only at one of the `=` to remove it. Instead, we now replace the whole thing (as we should have the whole time):
```
error: unknown start of token: \u{2a75}
--> $DIR/unicode-double-equals-recovery.rs:1:16
|
LL | const A: usize ⩵ 2;
| ^
|
help: Unicode character '⩵' (Two Consecutive Equals Signs) looks like '==' (Double Equals Sign), but it is not
|
LL | const A: usize == 2;
| ~~
error: unexpected `==`
--> $DIR/unicode-double-equals-recovery.rs:1:16
|
LL | const A: usize ⩵ 2;
| ^
|
help: try using `=` instead
|
LL | const A: usize = 2;
| ~
```
Make parse error suggestions verbose and fix spans
Go over all structured parser suggestions and make them verbose style.
When suggesting to add or remove delimiters, turn them into multiple suggestion parts.
Go over all structured parser suggestions and make them verbose style.
When suggesting to add or remove delimiters, turn them into multiple suggestion parts.
Support tail calls in mir via `TerminatorKind::TailCall`
This is one of the interesting bits in tail call implementation — MIR support.
This adds a new `TerminatorKind` which represents a tail call:
```rust
TailCall {
func: Operand<'tcx>,
args: Vec<Operand<'tcx>>,
fn_span: Span,
},
```
*Structurally* this is very similar to a normal `Call` but is missing a few fields:
- `destination` — tail calls don't write to destination, instead they pass caller's destination to the callee (such that eventual `return` will write to the caller of the function that used tail call)
- `target` — similarly to `destination` tail calls pass the caller's return address to the callee, so there is nothing to do
- `unwind` — I _think_ this is applicable too, although it's a bit confusing
- `call_source` — `become` forbids operators and is not created as a lowering of something else; tail calls always come from HIR (at least for now)
It might be helpful to read the interpreter implementation to understand what `TailCall` means exactly, although I've tried documenting it too.
-----
There are a few `FIXME`-questions still left, ideally we'd be able to answer them during review ':)
-----
r? `@oli-obk`
cc `@scottmcm` `@DrMeepster` `@JakobDegen`
Improve dead code analysis
Fixes#120770
1. check impl items later if self ty is private although the trait method is public, cause we must use the ty firstly if it's private
2. mark the adt live if it appears in pattern, like generic argument, this implies the use of the adt
3. based on the above, we can handle the case that private adts impl Default, so that we don't need adding rustc_trivial_field_reads on Default, and the logic in should_ignore_item
r? ``@pnkfelix``
Remove use of const traits (and `feature(effects)`) from stdlib
The current uses are already unsound because they are using non-const impls in const contexts. We can reintroduce them by reverting the commit in this PR, after #120639 lands.
Also, make `effects` an incomplete feature.
cc `@rust-lang/project-const-traits`
r? `@compiler-errors`
Fix `...` in multline code-skips in suggestions
When we have long code skips, we write `...` in the line number gutter.
For suggestions, we were "centering" the `...` with the line, but that was inconsistent with what we do in every other case *and* off-center.
Add a tidy rule to check that fluent messages and attrs don't end in `.`
This adds a new dependency on `fluent-parse` to `tidy` -- we already rely on it in rustc so I feel like it's not that big of a deal.
This PR also adjusts many error messages that currently end in `.`; not all of them since I added an `ALLOWLIST`, excluded `rustc_codegen_*` ftl files, and `.teach_note` attributes.
r? ``@estebank`` ``@oli-obk``
Improve conflict marker recovery
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closes#113826
r? ```@estebank``` since you reviewed #115413
cc: ```@rben01``` since you opened up the issue in the first place
When we have long code skips, we write `...` in the line number gutter.
For suggestions, we were "centering" the `...` with the line, but that was consistent with what we do in every other case.
Fix duplicated attributes on nonterminal expressions
This PR fixes a long-standing bug (#86055) whereby expression attributes can be duplicated when expanded through declarative macros.
First, consider how items are parsed in declarative macros:
```
Items:
- parse_nonterminal
- parse_item(ForceCollect::Yes)
- parse_item_
- attrs = parse_outer_attributes
- parse_item_common(attrs)
- maybe_whole!
- collect_tokens_trailing_token
```
The important thing is that the parsing of outer attributes is outside token collection, so the item's tokens don't include the attributes. This is how it's supposed to be.
Now consider how expression are parsed in declarative macros:
```
Exprs:
- parse_nonterminal
- parse_expr_force_collect
- collect_tokens_no_attrs
- collect_tokens_trailing_token
- parse_expr
- parse_expr_res(None)
- parse_expr_assoc_with
- parse_expr_prefix
- parse_or_use_outer_attributes
- parse_expr_dot_or_call
```
The important thing is that the parsing of outer attributes is inside token collection, so the the expr's tokens do include the attributes, i.e. in `AttributesData::tokens`.
This PR fixes the bug by rearranging expression parsing to that outer attribute parsing happens outside of token collection. This requires a number of small refactorings because expression parsing is somewhat complicated. While doing so the PR makes the code a bit cleaner and simpler, by eliminating `parse_or_use_outer_attributes` and `Option<AttrWrapper>` arguments (in favour of the simpler `parse_outer_attributes` and `AttrWrapper` arguments), and simplifying `LhsExpr`.
r? `@petrochenkov`
Spruce up the diagnostics of some early lints
Implement the various "*(note to myself) in a follow-up PR we should turn parts of this message into a subdiagnostic (help msg or even struct sugg)*" drive-by comments I left in #124417 during my review.
For context, before #124417, only a few early lints touched/decorated/customized their diagnostic because the former API made it a bit awkward. Likely because of that, things that should've been subdiagnostics were just crammed into the primary message. This PR rectifies this.
Detect pub structs never constructed and unused associated constants
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Lints never constructed public structs.
If we don't provide public methods to construct public structs with private fields, and don't construct them in the local crate. They would be never constructed. So that we can detect such public structs.
---
Update:
Also lints unused associated constants in traits.
Silence follow-up errors directly based on error types and regions
During type_of, we used to just return an error type if there were any errors encountered. This is problematic, because it means a struct declared as `struct Foo<'static>` will end up not finding any inherent or trait impls because those impl blocks' `Self` type will be `{type error}` instead of `Foo<'re_error>`. Now it's the latter, silencing nonsensical follow-up errors about `Foo` not having any methods.
Unfortunately that now allows for new follow-up errors, because borrowck treats `'re_error` as `'static`, causing nonsensical errors about non-error lifetimes not outliving `'static`. So what I also did was to just strip all outlives bounds that borrowck found, thus never letting it check them. There are probably more nuanced ways to do this, but I worried there would be other nonsensical errors if some outlives bounds were missing. Also from the test changes, it looked like an improvement everywhere.
Reject `CVarArgs` in `parse_ty_for_where_clause`
Fixes#125847. This regressed in #77035 where the `parse_ty` inside `parse_ty_where_predicate` was replaced with the at the time new `parse_ty_for_where_clause` which incorrectly stated it would permit CVarArgs (maybe a copy/paste error).
r? parser
