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Extend tests + improve description + general improvement

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This commit is contained in:
blyxyas 2023-03-11 21:30:34 +01:00
parent 2d572d4a9c
commit d65c9a5700
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5 changed files with 59 additions and 57 deletions
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84
clippy_lints/src/allow_attribute.rs
View File

@ -1,16 +1,27 @@
use ast::{AttrStyle, MetaItemKind};
use clippy_utils::{diagnostics::span_lint_and_sugg, source::snippet};
use ast::AttrStyle;
use clippy_utils::diagnostics::span_lint_and_sugg;
use rustc_ast as ast;
use rustc_errors::Applicability;
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{symbol::Ident, BytePos};
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// ### What it does
/// Detects uses of the `#[allow]` attribute and suggests to replace it with the new `#[expect]` attribute implemented by `#![feature(lint_reasons)]` ([RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
/// Detects uses of the `#[allow]` attribute and suggests replacing it with
/// the `#[expect]` (See [RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
///
/// The expect attribute is still unstable and requires the `lint_reasons`
/// on nightly. It can be enabled by adding `#![feature(lint_reasons)]` to
/// the crate root.
///
/// This lint only warns outer attributes (`#[allow]`), as inner attributes
/// (`#![allow]`) are usually used to enable or disable lints on a global scale.
///
/// ### Why is this bad?
/// Using `#[allow]` isn't bad, but `#[expect]` may be preferred as it lints if the code **doesn't** produce a warning.
///
/// `#[expect]` attributes suppress the lint emission, but emit a warning, if
/// the expectation is unfulfilled. This can be useful to be notified when the
/// lint is no longer triggered.
///
/// ### Example
/// ```rust,ignore
/// #[allow(unused_mut)]
@ -34,59 +45,34 @@ declare_clippy_lint! {
"`#[allow]` will not trigger if a warning isn't found. `#[expect]` triggers if there are no warnings."
}
pub struct AllowAttribute {
pub lint_reasons_active: bool,
}
impl_lint_pass!(AllowAttribute => [ALLOW_ATTRIBUTE]);
declare_lint_pass!(AllowAttribute => [ALLOW_ATTRIBUTE]);
impl LateLintPass<'_> for AllowAttribute {
// Separate each crate's features.
fn check_crate_post(&mut self, _: &LateContext<'_>) {
self.lint_reasons_active = false;
}
fn check_attribute(&mut self, cx: &LateContext<'_>, attr: &ast::Attribute) {
// Check inner attributes
if_chain! {
if let AttrStyle::Inner = attr.style;
if attr.ident()
.unwrap_or(Ident::with_dummy_span(sym!(empty))) // Will not trigger if doesn't have an ident.
.name == sym!(feature);
if let ast::AttrKind::Normal(normal) = &attr.kind;
if let Some(MetaItemKind::List(list)) = normal.item.meta_kind();
if let Some(symbol) = list.get(0);
if symbol.ident().unwrap().name == sym!(lint_reasons);
then {
self.lint_reasons_active = true;
}
}
// Check outer attributes
if_chain! {
if cx.tcx.features().lint_reasons;
if let AttrStyle::Outer = attr.style;
if attr.ident()
.unwrap_or(Ident::with_dummy_span(sym!(empty))) // Will not trigger if doesn't have an ident.
.name == sym!(allow);
if self.lint_reasons_active;
if let Some(ident) = attr.ident();
if ident.name == rustc_span::symbol::sym::allow;
then {
span_lint_and_sugg(
cx,
ALLOW_ATTRIBUTE,
attr.span,
ident.span,
"#[allow] attribute found",
"replace it with",
format!("#[expect{})]", snippet(
cx,
attr.ident().unwrap().span
.with_lo(
attr.ident().unwrap().span.hi() + BytePos(2) // Cut [(
)
.with_hi(
attr.meta().unwrap().span.hi() - BytePos(2) // Cut )]
)
, "...")), Applicability::MachineApplicable);
"replace it with", "expect".into()
// format!("expect{}", snippet(
// cx,
// ident.span
// .with_lo(
// ident.span.hi() + BytePos(2) // Cut *(
// )
// .with_hi(
// attr.meta().unwrap().span.hi() - BytePos(1) // Cut )
// )
// , "..."))
, Applicability::MachineApplicable);
}
}
}

6
clippy_lints/src/lib.rs
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@ -934,11 +934,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|_| Box::new(missing_assert_message::MissingAssertMessage));
store.register_early_pass(|| Box::new(redundant_async_block::RedundantAsyncBlock));
store.register_late_pass(|_| Box::new(let_with_type_underscore::UnderscoreTyped));
store.register_late_pass(|_| {
Box::new(allow_attribute::AllowAttribute {
lint_reasons_active: false,
})
});
store.register_late_pass(|_| Box::new(allow_attribute::AllowAttribute));
// add lints here, do not remove this comment, it's used in `new_lint`
}

7
tests/ui/allow_attribute.fixed
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@ -16,3 +16,10 @@ struct T2; // Should not lint
struct T3;
#[warn(clippy::needless_borrow)] // Should not lint
struct T4;
// `panic = "unwind"` should always be true
#[cfg_attr(panic = "unwind", expect(dead_code))]
struct CfgT;
fn ignore_inner_attr() {
#![allow(unused)] // Should not lint
}

7
tests/ui/allow_attribute.rs
View File

@ -16,3 +16,10 @@ struct T2; // Should not lint
struct T3;
#[warn(clippy::needless_borrow)] // Should not lint
struct T4;
// `panic = "unwind"` should always be true
#[cfg_attr(panic = "unwind", allow(dead_code))]
struct CfgT;
fn ignore_inner_attr() {
#![allow(unused)] // Should not lint
}

12
tests/ui/allow_attribute.stderr
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@ -1,10 +1,16 @@
error: #[allow] attribute found
--> $DIR/allow_attribute.rs:11:1
--> $DIR/allow_attribute.rs:11:3
|
LL | #[allow(dead_code)]
| ^^^^^^^^^^^^^^^^^^^ help: replace it with: `#[expect(dead_code)]`
| ^^^^^ help: replace it with: `expect`
|
= note: `-D clippy::allow-attribute` implied by `-D warnings`
error: aborting due to previous error
error: #[allow] attribute found
--> $DIR/allow_attribute.rs:20:30
|
LL | #[cfg_attr(panic = "unwind", allow(dead_code))]
| ^^^^^ help: replace it with: `expect`
error: aborting due to 2 previous errors