//! lint when there is an enum with no variants
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
use rustc::hir::*;
-use utils::span_lint_and_then;
+use crate::utils::span_lint_and_then;
/// **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,
+/// **Why is this bad?** Enum's with no variants should be replaced with `!`,
+/// the uninhabited type,
/// or a wrapper around it.
///
/// **Known problems:** None.
/// ```rust
/// enum Test {}
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub EMPTY_ENUM,
- Allow,
+ pedantic,
"enum with no variants"
}
-#[derive(Copy,Clone)]
+#[derive(Copy, Clone)]
pub struct EmptyEnum;
impl LintPass for 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 {
+ 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");