Implement destructuring assignment for structs and slices
This is the second step towards implementing destructuring assignment (RFC: rust-lang/rfcs#2909, tracking issue: #71126). This PR is the second part of #71156, which was split up to allow for easier review.
Note that the first PR (#78748) is not merged yet, so it is included as the first commit in this one. I thought this would allow the review to start earlier because I have some time this weekend to respond to reviews. If ``@petrochenkov`` prefers to wait until the first PR is merged, I totally understand, of course.
This PR implements destructuring assignment for (tuple) structs and slices. In order to do this, the following *parser change* was necessary: struct expressions are not required to have a base expression, i.e. `Struct { a: 1, .. }` becomes legal (in order to act like a struct pattern).
Unfortunately, this PR slightly regresses the diagnostics implemented in #77283. However, it is only a missing help message in `src/test/ui/issues/issue-77218.rs`. Other instances of this diagnostic are not affected. Since I don't exactly understand how this help message works and how to fix it yet, I was hoping it's OK to regress this temporarily and fix it in a follow-up PR.
Thanks to ``@varkor`` who helped with the implementation, particularly around the struct rest changes.
r? ``@petrochenkov``
We skip the lint if the `loop {}` is in the `#[panic_handler]` as the
main recommendation we give is to panic, which obviously isn't
possible in a panic handler.
Signed-off-by: Joe Richey <joerichey@google.com>
Check when `from_utf8` is called from sliced byte array from string
---
*Please keep the line below*
changelog: Fix#5487: Add linter to check when `from_utf8` is called from sliced byte array from string.
Provide diagnostic suggestion in ExprUseVisitor Delegate
The [Delegate trait](981346fc07/compiler/rustc_typeck/src/expr_use_visitor.rs (L28-L38)) currently use `PlaceWithHirId` which is composed of Hir `Place` and the
corresponding expression id.
Even though this is an accurate way of expressing how a Place is used,
it can cause confusion during diagnostics.
Eg:
```
let arr : [String; 5];
let [a, ...] = arr;
^^^ E1 ^^^ = ^^E2^^
```
Here `arr` is moved because of the binding created E1. However, when we
point to E1 in diagnostics with the message `arr` was moved, it can be
confusing. Rather we would like to report E2 to the user.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/20
r? `@ghost`
Use const sym where possible
I ran a regex search and replace to use const `sym` values where possible. This should give some performance boost by avoiding string interning at runtime.
Con: It is not as consistent as always using `sym!`.
I also changed an internal lint to suggest using `sym::{}`, making an assumption that this will always work for diagnostic items.
changelog: none
Add lint: from_iter_instead_of_collect
Fixes#5679
This implements lint for `::from_iter()` from #5679 not the general issue (`std::ops::Add::add`, etc.).
This lint checks if expression is function call with `from_iter` name and if it's implementation of the `std::iter::FromIterator` trait.
changelog: Introduce from_iter_instead_of_collect lint
single_char_insert_str: lint using insert_str() on single-char literals and suggest insert()
Fixes#6026
changelog: add single_char_insert_str lint which lints using string.insert_str() with single char literals and suggests string.insert() with a char
The [Delegate
trait](981346fc07/compiler/rustc_typeck/src/expr_use_visitor.rs (L28-L38))
currently use `PlaceWithHirId` which is composed of Hir `Place` and the
corresponding expression id.
Even though this is an accurate way of expressing how a Place is used,
it can cause confusion during diagnostics.
Eg:
```
let arr : [String; 5];
let [a, ...] = arr;
^^^ E1 ^^^ = ^^E2^^
```
Here `arr` is moved because of the binding created E1. However, when we
point to E1 in diagnostics with the message `arr` was moved, it can be
confusing. Rather we would like to report E2 to the user.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/20
Hex bin digit grouping
This revives and updates an old pr (#3391) for the current API.
Closes#2538.
---
*Please keep the line below*
changelog: Add [`unusual_byte_groupings`] lint.
Split out statement attributes changes from #78306
This is the same as PR https://github.com/rust-lang/rust/pull/78306, but `unused_doc_comments` is modified to explicitly ignore statement items (which preserves the current behavior).
This shouldn't have any user-visible effects, so it can be landed without lang team discussion.
---------
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
```rust
trait Foo {
#[allow(unused_attributes)] #[inline] fn first();
#[inline] #[allow(unused_attributes)] fn second();
}
```
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
Add lint for holding RefCell Ref across an await
Fixes#6008
This introduces the lint await_holding_refcell_ref. For async functions, we iterate
over all types in generator_interior_types and look for `core::cell::Ref` or `core::cell::RefMut`. If we find one then we emit a lint.
Heavily cribs from: https://github.com/rust-lang/rust-clippy/pull/5439
changelog: introduce the await_holding_refcell_ref lint
Refactor trivially_copy_pass_by_ref and the new lint into pass_by_ref_or_value module
Update stderr of conf_unknown_key test
Rename lint to large_types_passed_by_value
Increase `pass_by_value_size_limit` default value to 256
Improve rules for `large_types_passed_by_value`
Improve tests for `large_types_passed_by_value`
Improve documentation for `large_types_passed_by_value`
Make minor corrections to pass_by_ref_or_value.rs suggested by clippy itself
Fix `large_types_passed_by_value` example and improve docs
pass_by_ref_or_value: Tweak check for mut annotation in params
large_types_passed_by_value: add tests for pub trait, trait impl and inline attributes
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
```rust
trait Foo {
#[allow(unused_attributes)] #[inline] fn first();
#[inline] #[allow(unused_attributes)] fn second();
}
```
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
Identical arguments on assert macro family
Lint when identical args are used on `assert_eq!`, `debug_assert_eq!`, `assert_ne!` and `debug_assert_ne!` macros.
Added to the lint `eq_op`.
Common functions added to `utils/higher.rs`
Fixes: #3574Fixes: #4694
changelog: Lint on identical args when calling `assert_eq!`, `debug_assert_eq!`, `assert_ne!` and `debug_assert_ne!` macros
BTreeMap: refactor Entry out of map.rs into its own file
btree/map.rs is approaching the 3000 line mark, splitting out the entry
code buys about 500 lines of headroom.
I've created this PR because the changes I've made in #77438 will push `map.rs` over the 3000 line limit and cause tidy to complain.
I picked `Entry` to factor out because it feels less tightly coupled to the rest of `BTreeMap` than the various iterator implementations.
Related: #60302
Expands `manual_memcpy` to lint ones with loop counters
Closes#1670
This PR expands `manual_memcpy` to lint ones with loop counters as described in https://github.com/rust-lang/rust-clippy/issues/1670#issuecomment-293280204
Although the current code is working, I have a couple of questions and concerns.
~~Firstly, I manually implemented `Clone` for `Sugg` because `AssocOp` lacks `Clone`. As `AssocOp` only holds an enum, which is `Copy`, as a value, it seems `AssocOp` can be `Clone`; but, I was not sure where to ask it. Should I make a PR to `rustc`?~~ The [PR]( https://github.com/rust-lang/rust/pull/73629) was made.
Secondly, manual copying with loop counters are likely to trigger `needless_range_loop` and `explicit_counter_loop` along with `manual_memcpy`; in fact, I explicitly allowed them in the tests. Is there any way to disable these two lints when a code triggers `manual_memcpy`?
And, another thing I'd like to note is that `Sugg` adds unnecessary parentheses when expressions with parentheses passed to its `hir` function, as seen here:
```
error: it looks like you're manually copying between slices
--> $DIR/manual_memcpy.rs:145:14
|
LL | for i in 3..(3 + src.len()) {
| ^^^^^^^^^^^^^^^^^^ help: try replacing the loop by: `dst[3..((3 + src.len()))].clone_from_slice(&src[..((3 + src.len()) - 3)])
```
However, using the `hir` function is needed to prevent the suggestion causing errors when users use bitwise operations; and also this have already existed, for example: `verbose_bit_mask`. Thus, I think this is fine.
changelog: Expands `manual_memcpy` to lint ones with loop counters
Revert: or_fun_call should lint calls to `const fn`s with no args
The changes in #5889 and #5984 were done under the incorrect assumption that a `const fn` with no args was guaranteed to be evaluated at compile time. A `const fn` is only guaranteed to be evaluated at compile time if it's inside a const context (the initializer of a `const` or a `static`).
See this [zulip conversation](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/Common.20misconception.3A.20.60const.20fn.60.20and.20its.20effect.20on.20codegen/near/208059113) for more details on this common misconception.
Given that none of the linted methods by `or_fun_call` can be called in const contexts, the lint should make no exceptions.
changelog: [`or_fun_call`] lints again calls to `const fn` with no args
Add `rc_buffer` lint for checking Rc<String> and friends
Fixes#2623
This is a bit different from the original PR attempting to implement this type of lint. Rather than linting against converting into the unwanted types, this PR lints against declaring the unwanted type in a struct or function definition.
I'm reasonably happy with what I have here, although I used the fully qualified type names for the Path and OsString suggestions, and I'm not sure if I should have just used the short versions instead, even if they might not have been declared via use.
Also, I don't know if "buffer type" is the best way to put it or not. Alternatively I could call it a "growable type" or "growable buffer type", but I was thinking of PathBuf when I started making the lint.
changelog: Add `rc_buffer` lint
option_if_let_else - distinguish pure from impure else expressions
Addresses partially #5821.
changelog: improve the lint `option_if_let_else`. Suggest `map_or` or `map_or_else` based on the else expression purity.
Add a new lint, `manual-strip`, that suggests using the `str::strip_prefix`
and `str::strip_suffix` methods introduced in Rust 1.45 when the same
functionality is performed 'manually'.
Closes#5734
Attach tokens to all AST types used in `Nonterminal`
We perform token capturing when we have outer attributes (for nonterminals that support attributes - e.g. `Stmt`), or when we parse a `Nonterminal` for a `macro_rules!` argument. The full list of `Nonterminals` affected by this PR is:
* `NtBlock`
* `NtStmt`
* `NtTy`
* `NtMeta`
* `NtPath`
* `NtVis`
* `NtLiteral`
Of these nonterminals, only `NtStmt` and `NtLiteral` (which is actually just an `Expr`), support outer attributes - the rest only ever have token capturing perform when they match a `macro_rules!` argument.
This makes progress towards solving https://github.com/rust-lang/rust/issues/43081 - we now collect tokens for everything that might need them. However, we still need to handle `#[cfg]`, inner attributes, and misc pretty-printing issues (e.g. #75734)
I've separated the changes into (mostly) independent commits, which could be split into individual PRs for each `Nonterminal` variant. The purpose of having them all in one PR is to do a single Crater run for all of them.
Most of the changes in this PR are trivial (adding `tokens: None` everywhere we construct the various AST structs). The significant changes are:
* `ast::Visibility` is changed from `type Visibility = Spanned<VisibilityKind>` to a `struct Visibility { kind, span, tokens }`.
* `maybe_collect_tokens` is made generic, and used for both `ast::Expr` and `ast::Stmt`.
* Some of the statement-parsing functions are refactored so that we can capture the trailing semicolon.
* `Nonterminal` and `Expr` both grew by 8 bytes, as some of the structs which are stored inline (rather than behind a `P`) now have an `Option<TokenStream>` field. Hopefully the performance impact of doing this is negligible.
make a bunch of lints texts adhere to rustc dev guide
According to the rustc-dev guide: "The text should be matter of fact and avoid capitalization and periods, unless multiple sentences are needed"
changelog: make some lint output adhere to the rustc-dev guide
By moving `{known,used}_attrs` from `SessionGlobals` to `Session`. This
means they are accessed via the `Session`, rather than via TLS. A few
`Attr` methods and `librustc_ast` functions are now methods of
`Session`.
All of this required passing a `Session` to lots of functions that didn't
already have one. Some of these functions also had arguments removed, because
those arguments could be accessed directly via the `Session` argument.
`contains_feature_attr()` was dead, and is removed.
Some functions were moved from `librustc_ast` elsewhere because they now need
to access `Session`, which isn't available in that crate.
- `entry_point_type()` --> `librustc_builtin_macros`
- `global_allocator_spans()` --> `librustc_metadata`
- `is_proc_macro_attr()` --> `Session`
try_err: Consider Try impl for Poll when generating suggestions
There are two different implementation of `Try` trait for `Poll` type:
`Poll<Result<T, E>>` and `Poll<Option<Result<T, E>>>`. Take them into
account when generating suggestions.
For example, for `Err(e)?` suggest either `return Poll::Ready(Err(e))` or
`return Poll::Ready(Some(Err(e)))` as appropriate.
Fixes#5855
changelog: try_err: Consider Try impl for Poll when generating suggestions
For consistency with `Attribute::has_name` which doesn't mark the attribute as used either.
Replace all uses of `check_name` with `has_name` outside of rustc
There are two different implementation of Try trait for Poll type;
Poll<Result<T, E>> and Poll<Option<Result<T, E>>>. Take them into
account when generating suggestions.
For example, for Err(e)? suggest either return Poll::Ready(Err(e)) or
return Poll::Ready(Some(Err(e))) as appropriate.
