Address flip1995's review comments

This commit is contained in:
nahuakang 2021-01-04 17:47:59 +01:00
parent 275988cb73
commit bc97f5d215
2 changed files with 16 additions and 6 deletions

View File

@ -8,12 +8,12 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// **What it does:** Checks for `enum`s with no variants.
///
/// As of this writing, the never type is still a
/// As of this writing, the `never_type` is still a
/// nightly-only experimental API. Therefore, this lint is only triggered
/// if the never type is enabled
/// if the `never_type` is enabled.
///
/// **Why is this bad?** If you want to introduce a type which
/// can't be instantiated, you should use `!` (the never type),
/// can't be instantiated, you should use `!` (the primitive type never),
/// or a wrapper around it, because `!` has more extensive
/// compiler support (type inference, etc...) and wrappers
/// around it are the conventional way to define an uninhabited type.
@ -44,13 +44,16 @@ declare_lint_pass!(EmptyEnum => [EMPTY_ENUM]);
impl<'tcx> LateLintPass<'tcx> for EmptyEnum {
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
// Only suggest the `never_type` if the feature is enabled
if !cx.tcx.features().never_type {
return;
}
let did = cx.tcx.hir().local_def_id(item.hir_id);
if let ItemKind::Enum(..) = item.kind {
let ty = cx.tcx.type_of(did);
let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
// Only suggest the never type if the feature is enabled
if adt.variants.is_empty() && cx.tcx.features().never_type {
if adt.variants.is_empty() {
span_lint_and_help(
cx,
EMPTY_ENUM,

View File

@ -0,0 +1,7 @@
#![allow(dead_code)]
#![warn(clippy::empty_enum)]
// `never_type` is not enabled; this test has no stderr file
enum Empty {}
fn main() {}