1 //! lint on `use`ing all variants of an enum
4 use rustc::hir::def::Def;
5 use rustc::hir::map::Node::NodeItem;
6 use rustc::lint::{LateLintPass, LintPass, LateContext, LintArray, LintContext};
7 use syntax::ast::NodeId;
8 use syntax::codemap::Span;
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::*;
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 LateLintPass for EnumGlobUse {
38 fn check_mod(&mut self, cx: &LateContext, m: &Mod, _: Span, _: NodeId) {
39 // only check top level `use` statements
40 for item in &m.item_ids {
41 self.lint_item(cx, cx.krate.item(item.id));
47 fn lint_item(&self, cx: &LateContext, item: &Item) {
48 if item.vis == Visibility::Public {
49 return; // re-exports are fine
51 if let ItemUse(ref item_use) = item.node {
52 if let ViewPath_::ViewPathGlob(_) = item_use.node {
53 if let Some(def) = cx.tcx.def_map.borrow().get(&item.id) {
54 if let Some(node_id) = cx.tcx.map.as_local_node_id(def.full_def().def_id()) {
55 if let Some(NodeItem(it)) = cx.tcx.map.find(node_id) {
56 if let ItemEnum(..) = it.node {
57 span_lint(cx, ENUM_GLOB_USE, item.span, "don't use glob imports for enum variants");
61 let child = cx.sess().cstore.item_children(def.full_def().def_id());
62 if let Some(child) = child.first() {
63 if let Some(Def::Variant(..)) = cx.tcx.sess.cstore.describe_def(child.def_id) {
64 span_lint(cx, ENUM_GLOB_USE, item.span, "don't use glob imports for enum variants");