//! lint when there is an enum with no variants
-use rustc::lint::*;
+use crate::utils::span_lint_and_then;
use rustc::hir::*;
-use utils::span_lint_and_then;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
-/// **What it does:** Checks for `enum`s with no variants.
-///
-/// **Why is this bad?** Enum's with no variants should be replaced with `!`,
-/// the uninhabited type,
-/// or a wrapper around it.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// enum Test {}
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for `enum`s with no variants.
+ ///
+ /// **Why is this bad?** Enum's with no variants should be replaced with `!`,
+ /// the uninhabited type,
+ /// or a wrapper around it.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// enum Test {}
+ /// ```
pub EMPTY_ENUM,
pedantic,
"enum with no variants"
fn get_lints(&self) -> LintArray {
lint_array!(EMPTY_ENUM)
}
+
+ fn name(&self) -> &'static str {
+ "EmptyEnum"
+ }
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EmptyEnum {
- fn check_item(&mut self, cx: &LateContext, item: &Item) {
- let did = cx.tcx.hir.local_def_id(item.id);
- if let ItemEnum(..) = item.node {
+ fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &Item) {
+ let did = cx.tcx.hir().local_def_id_from_hir_id(item.hir_id);
+ if let ItemKind::Enum(..) = item.node {
let ty = cx.tcx.type_of(did);
- let adt = ty.ty_adt_def()
- .expect("already checked whether this is an enum");
+ let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
if adt.variants.is_empty() {
span_lint_and_then(cx, EMPTY_ENUM, item.span, "enum with no variants", |db| {
- db.span_help(item.span, "consider using the uninhabited type `!` or a wrapper around it");
+ db.span_help(
+ item.span,
+ "consider using the uninhabited type `!` or a wrapper around it",
+ );
});
}
}