1 //! lint on `use`ing all variants of an enum
4 use rustc::hir::def::Def;
5 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
6 use rustc::{declare_lint, lint_array};
7 use syntax::ast::NodeId;
8 use syntax::codemap::Span;
9 use crate::utils::span_lint;
11 /// **What it does:** Checks for `use Enum::*`.
13 /// **Why is this bad?** It is usually better style to use the prefixed name of
14 /// an enumeration variant, rather than importing variants.
16 /// **Known problems:** Old-style enumerations that prefix the variants are
21 /// use std::cmp::Ordering::*;
23 declare_clippy_lint! {
26 "use items that import all variants of an enum"
29 pub struct EnumGlobUse;
31 impl LintPass for EnumGlobUse {
32 fn get_lints(&self) -> LintArray {
33 lint_array!(ENUM_GLOB_USE)
37 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EnumGlobUse {
38 fn check_mod(&mut self, cx: &LateContext<'a, 'tcx>, m: &'tcx Mod, _: Span, _: NodeId) {
39 // only check top level `use` statements
40 for item in &m.item_ids {
41 self.lint_item(cx, cx.tcx.hir.expect_item(item.id));
47 fn lint_item(&self, cx: &LateContext, item: &Item) {
48 if item.vis.node.is_pub() {
49 return; // re-exports are fine
51 if let ItemKind::Use(ref path, UseKind::Glob) = item.node {
52 if let Def::Enum(_) = path.def {
57 "don't use glob imports for enum variants",