rust/clippy_lints/src/exhaustive_items.rs

107 lines
3.4 KiB
Rust

use crate::utils::{indent_of, span_lint_and_then};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{Item, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
declare_clippy_lint! {
/// **What it does:** Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
///
/// **Why is this bad?** Exhaustive enums are typically fine, but a project which does
/// not wish to make a stability commitment around exported enums may wish to
/// disable them by default.
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```rust
/// enum Foo {
/// Bar,
/// Baz
/// }
/// ```
/// Use instead:
/// ```rust
/// #[non_exhaustive]
/// enum Foo {
/// Bar,
/// Baz
/// }
/// ```
pub EXHAUSTIVE_ENUMS,
restriction,
"detects exported enums that have not been marked #[non_exhaustive]"
}
declare_clippy_lint! {
/// **What it does:** Warns on any exported `structs`s that are not tagged `#[non_exhaustive]`
///
/// **Why is this bad?** Exhaustive structs are typically fine, but a project which does
/// not wish to make a stability commitment around exported structs may wish to
/// disable them by default.
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```rust
/// struct Foo {
/// bar: u8,
/// baz: String,
/// }
/// ```
/// Use instead:
/// ```rust
/// #[non_exhaustive]
/// struct Foo {
/// bar: u8,
/// baz: String,
/// }
/// ```
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<'_>) {
if_chain! {
if let ItemKind::Enum(..) | ItemKind::Struct(..) = item.kind;
if cx.access_levels.is_exported(item.hir_id);
if !item.attrs.iter().any(|a| a.has_name(sym::non_exhaustive));
then {
let (lint, msg) = if let ItemKind::Struct(ref v, ..) = item.kind {
if v.fields().iter().any(|f| !f.vis.node.is_pub()) {
// skip structs with private fields
return;
}
(EXHAUSTIVE_STRUCTS, "exported structs should not be exhaustive")
} else {
(EXHAUSTIVE_ENUMS, "exported enums should not be exhaustive")
};
let suggestion_span = item.span.shrink_to_lo();
let indent = " ".repeat(indent_of(cx, item.span).unwrap_or(0));
span_lint_and_then(
cx,
lint,
item.span,
msg,
|diag| {
let sugg = format!("#[non_exhaustive]\n{}", indent);
diag.span_suggestion(suggestion_span,
"try adding #[non_exhaustive]",
sugg,
Applicability::MaybeIncorrect);
}
);
}
}
}
}