mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-28 07:30:57 +00:00
75 lines
2.6 KiB
Rust
75 lines
2.6 KiB
Rust
use ast::{AttrStyle, Attribute};
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::is_from_proc_macro;
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use rustc_ast as ast;
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use rustc_errors::Applicability;
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use rustc_lint::{LateContext, LateLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for usage of the `#[allow]` attribute and suggests replacing it with
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/// the `#[expect]` (See [RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
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///
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/// The expect attribute is still unstable and requires the `lint_reasons`
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/// on nightly. It can be enabled by adding `#![feature(lint_reasons)]` to
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/// the crate root.
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///
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/// This lint only warns outer attributes (`#[allow]`), as inner attributes
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/// (`#![allow]`) are usually used to enable or disable lints on a global scale.
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///
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/// ### Why is this bad?
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/// `#[expect]` attributes suppress the lint emission, but emit a warning, if
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/// the expectation is unfulfilled. This can be useful to be notified when the
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/// lint is no longer triggered.
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///
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/// ### Example
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/// ```rust,ignore
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/// #[allow(unused_mut)]
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/// fn foo() -> usize {
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/// let mut a = Vec::new();
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/// a.len()
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/// }
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/// ```
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/// Use instead:
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/// ```rust,ignore
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/// #![feature(lint_reasons)]
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/// #[expect(unused_mut)]
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/// fn foo() -> usize {
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/// let mut a = Vec::new();
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/// a.len()
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/// }
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/// ```
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#[clippy::version = "1.70.0"]
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pub ALLOW_ATTRIBUTES,
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restriction,
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"`#[allow]` will not trigger if a warning isn't found. `#[expect]` triggers if there are no warnings."
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}
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declare_lint_pass!(AllowAttribute => [ALLOW_ATTRIBUTES]);
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impl LateLintPass<'_> for AllowAttribute {
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// Separate each crate's features.
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fn check_attribute<'cx>(&mut self, cx: &LateContext<'cx>, attr: &'cx Attribute) {
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if_chain! {
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if !in_external_macro(cx.sess(), attr.span);
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if cx.tcx.features().lint_reasons;
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if let AttrStyle::Outer = attr.style;
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if let Some(ident) = attr.ident();
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if ident.name == rustc_span::symbol::sym::allow;
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if !is_from_proc_macro(cx, &attr);
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then {
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span_lint_and_sugg(
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cx,
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ALLOW_ATTRIBUTES,
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ident.span,
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"#[allow] attribute found",
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"replace it with",
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"expect".into(),
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Applicability::MachineApplicable,
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);
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}
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}
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}
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}
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