rust/clippy_lints/src/exhaustive_items.rs

105 lines
3.3 KiB
Rust

use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::indent_of;
use rustc_errors::Applicability;
use rustc_hir::{Item, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::declare_lint_pass;
use rustc_span::sym;
declare_clippy_lint! {
/// ### What it does
/// Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
///
/// ### Why restrict this?
/// Making an `enum` exhaustive is a stability commitment: adding a variant is a breaking change.
/// A project may wish to ensure that there are no exhaustive enums or that every exhaustive
/// `enum` is explicitly `#[allow]`ed.
///
/// ### Example
/// ```no_run
/// enum Foo {
/// Bar,
/// Baz
/// }
/// ```
/// Use instead:
/// ```no_run
/// #[non_exhaustive]
/// enum Foo {
/// Bar,
/// Baz
/// }
/// ```
#[clippy::version = "1.51.0"]
pub EXHAUSTIVE_ENUMS,
restriction,
"detects exported enums that have not been marked #[non_exhaustive]"
}
declare_clippy_lint! {
/// ### What it does
/// Warns on any exported `struct`s that are not tagged `#[non_exhaustive]`
///
/// ### Why restrict this?
/// Making a `struct` exhaustive is a stability commitment: adding a field is a breaking change.
/// A project may wish to ensure that there are no exhaustive structs or that every exhaustive
/// `struct` is explicitly `#[allow]`ed.
///
/// ### Example
/// ```no_run
/// struct Foo {
/// bar: u8,
/// baz: String,
/// }
/// ```
/// Use instead:
/// ```no_run
/// #[non_exhaustive]
/// struct Foo {
/// bar: u8,
/// baz: String,
/// }
/// ```
#[clippy::version = "1.51.0"]
pub EXHAUSTIVE_STRUCTS,
restriction,
"detects exported structs that have not been marked #[non_exhaustive]"
}
declare_lint_pass!(ExhaustiveItems => [EXHAUSTIVE_ENUMS, EXHAUSTIVE_STRUCTS]);
impl LateLintPass<'_> for ExhaustiveItems {
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
let (lint, msg, fields) = match item.kind {
ItemKind::Enum(..) => (
EXHAUSTIVE_ENUMS,
"exported enums should not be exhaustive",
[].as_slice(),
),
ItemKind::Struct(v, ..) => (
EXHAUSTIVE_STRUCTS,
"exported structs should not be exhaustive",
v.fields(),
),
_ => return,
};
if cx.effective_visibilities.is_exported(item.owner_id.def_id)
&& let attrs = cx.tcx.hir().attrs(item.hir_id())
&& !attrs.iter().any(|a| a.has_name(sym::non_exhaustive))
&& fields.iter().all(|f| cx.tcx.visibility(f.def_id).is_public())
{
span_lint_and_then(cx, lint, item.span, msg, |diag| {
let suggestion_span = item.span.shrink_to_lo();
let indent = " ".repeat(indent_of(cx, item.span).unwrap_or(0));
let sugg = format!("#[non_exhaustive]\n{indent}");
diag.span_suggestion_verbose(
suggestion_span,
"try adding #[non_exhaustive]",
sugg,
Applicability::MaybeIncorrect,
);
});
}
}
}