src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs

   1 use clippy_utils::diagnostics::span_lint_and_then;
   2 use rustc_errors::Applicability;
   3 use rustc_hir::def::{DefKind, Res};
   4 use rustc_hir::{Item, ItemKind};
   5 use rustc_lint::{LateContext, LateLintPass};
   6 use rustc_middle::ty;
   7 use rustc_session::{declare_tool_lint, impl_lint_pass};
   8 use rustc_span::def_id::CRATE_DEF_ID;
   9 use rustc_span::hygiene::MacroKind;
  10
  11 declare_clippy_lint! {
  12     /// ### What it does
  13     /// Checks for items declared `pub(crate)` that are not crate visible because they
  14     /// are inside a private module.
  15     ///
  16     /// ### Why is this bad?
  17     /// Writing `pub(crate)` is misleading when it's redundant due to the parent
  18     /// module's visibility.
  19     ///
  20     /// ### Example
  21     /// ```rust
  22     /// mod internal {
  23     ///     pub(crate) fn internal_fn() { }
  24     /// }
  25     /// ```
  26     /// This function is not visible outside the module and it can be declared with `pub` or
  27     /// private visibility
  28     /// ```rust
  29     /// mod internal {
  30     ///     pub fn internal_fn() { }
  31     /// }
  32     /// ```
  33     #[clippy::version = "1.44.0"]
  34     pub REDUNDANT_PUB_CRATE,
  35     nursery,
  36     "Using `pub(crate)` visibility on items that are not crate visible due to the visibility of the module that contains them."
  37 }
  38
  39 #[derive(Default)]
  40 pub struct RedundantPubCrate {
  41     is_exported: Vec<bool>,
  42 }
  43
  44 impl_lint_pass!(RedundantPubCrate => [REDUNDANT_PUB_CRATE]);
  45
  46 impl<'tcx> LateLintPass<'tcx> for RedundantPubCrate {
  47     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
  48         if_chain! {
  49             if cx.tcx.visibility(item.owner_id.def_id) == ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id());
  50             if !cx.effective_visibilities.is_exported(item.owner_id.def_id) && self.is_exported.last() == Some(&false);
  51             if is_not_macro_export(item);
  52             then {
  53                 let span = item.span.with_hi(item.ident.span.hi());
  54                 let descr = cx.tcx.def_kind(item.owner_id).descr(item.owner_id.to_def_id());
  55                 span_lint_and_then(
  56                     cx,
  57                     REDUNDANT_PUB_CRATE,
  58                     span,
  59                     &format!("pub(crate) {descr} inside private module"),
  60                     |diag| {
  61                         diag.span_suggestion(
  62                             item.vis_span,
  63                             "consider using",
  64                             "pub".to_string(),
  65                             Applicability::MachineApplicable,
  66                         );
  67                     },
  68                 );
  69             }
  70         }
  71
  72         if let ItemKind::Mod { .. } = item.kind {
  73             self.is_exported
  74                 .push(cx.effective_visibilities.is_exported(item.owner_id.def_id));
  75         }
  76     }
  77
  78     fn check_item_post(&mut self, _cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
  79         if let ItemKind::Mod { .. } = item.kind {
  80             self.is_exported.pop().expect("unbalanced check_item/check_item_post");
  81         }
  82     }
  83 }
  84
  85 fn is_not_macro_export<'tcx>(item: &'tcx Item<'tcx>) -> bool {
  86     if let ItemKind::Use(path, _) = item.kind {
  87         if path
  88             .res
  89             .iter()
  90             .all(|res| matches!(res, Res::Def(DefKind::Macro(MacroKind::Bang), _)))
  91         {
  92             return false;
  93         }
  94     } else if let ItemKind::Macro(..) = item.kind {
  95         return false;
  96     }
  97
  98     true
  99 }