| //! lint on `use`ing all variants of an enum |
| |
| use crate::utils::span_lint; |
| use rustc::hir::def::{DefKind, Res}; |
| use rustc::hir::*; |
| use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; |
| use rustc::{declare_lint_pass, declare_tool_lint}; |
| use syntax::source_map::Span; |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for `use Enum::*`. |
| /// |
| /// **Why is this bad?** It is usually better style to use the prefixed name of |
| /// an enumeration variant, rather than importing variants. |
| /// |
| /// **Known problems:** Old-style enumerations that prefix the variants are |
| /// still around. |
| /// |
| /// **Example:** |
| /// ```rust |
| /// use std::cmp::Ordering::*; |
| /// ``` |
| pub ENUM_GLOB_USE, |
| pedantic, |
| "use items that import all variants of an enum" |
| } |
| |
| declare_lint_pass!(EnumGlobUse => [ENUM_GLOB_USE]); |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EnumGlobUse { |
| fn check_mod(&mut self, cx: &LateContext<'a, 'tcx>, m: &'tcx Mod, _: Span, _: HirId) { |
| let map = cx.tcx.hir(); |
| // only check top level `use` statements |
| for item in &m.item_ids { |
| self.lint_item(cx, map.expect_item(item.id)); |
| } |
| } |
| } |
| |
| impl EnumGlobUse { |
| fn lint_item(self, cx: &LateContext<'_, '_>, item: &Item) { |
| if item.vis.node.is_pub() { |
| return; // re-exports are fine |
| } |
| if let ItemKind::Use(ref path, UseKind::Glob) = item.node { |
| if let Res::Def(DefKind::Enum, _) = path.res { |
| span_lint(cx, ENUM_GLOB_USE, item.span, "don't use glob imports for enum variants"); |
| } |
| } |
| } |
| } |