1 //! lint on `use`ing all variants of an enum
3 use crate::utils::span_lint;
4 use rustc::hir::def::Def;
6 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
7 use rustc::{declare_tool_lint, lint_array};
8 use syntax::source_map::Span;
10 declare_clippy_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::*;
25 "use items that import all variants of an enum"
28 pub struct EnumGlobUse;
30 impl LintPass for EnumGlobUse {
31 fn get_lints(&self) -> LintArray {
32 lint_array!(ENUM_GLOB_USE)
35 fn name(&self) -> &'static str {
40 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EnumGlobUse {
41 fn check_mod(&mut self, cx: &LateContext<'a, 'tcx>, m: &'tcx Mod, _: Span, _: HirId) {
42 let map = cx.tcx.hir();
43 // only check top level `use` statements
44 for item in &m.item_ids {
45 self.lint_item(cx, map.expect_item(map.hir_to_node_id(item.id)));
51 fn lint_item(&self, cx: &LateContext<'_, '_>, item: &Item) {
52 if item.vis.node.is_pub() {
53 return; // re-exports are fine
55 if let ItemKind::Use(ref path, UseKind::Glob) = item.node {
56 if let Def::Enum(_) = path.def {
57 span_lint(cx, ENUM_GLOB_USE, item.span, "don't use glob imports for enum variants");