New upstream version 1.52.1+dfsg1

[rustc.git] / src / tools / clippy / clippy_lints / src / redundant_pub_crate.rs

diff --git a/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
new file mode 100644 (file)
index 0000000..c876bae
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
@@ -0,0 +1,77 @@
+use crate::utils::span_lint_and_then;
+use rustc_errors::Applicability;
+use rustc_hir::{Item, ItemKind, VisibilityKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for items declared `pub(crate)` that are not crate visible because they
+    /// are inside a private module.
+    ///
+    /// **Why is this bad?** Writing `pub(crate)` is misleading when it's redundant due to the parent
+    /// module's visibility.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// mod internal {
+    ///     pub(crate) fn internal_fn() { }
+    /// }
+    /// ```
+    /// This function is not visible outside the module and it can be declared with `pub` or
+    /// private visibility
+    /// ```rust
+    /// mod internal {
+    ///     pub fn internal_fn() { }
+    /// }
+    /// ```
+    pub REDUNDANT_PUB_CRATE,
+    nursery,
+    "Using `pub(crate)` visibility on items that are not crate visible due to the visibility of the module that contains them."
+}
+
+#[derive(Default)]
+pub struct RedundantPubCrate {
+    is_exported: Vec<bool>,
+}
+
+impl_lint_pass!(RedundantPubCrate => [REDUNDANT_PUB_CRATE]);
+
+impl<'tcx> LateLintPass<'tcx> for RedundantPubCrate {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
+        if let VisibilityKind::Crate { .. } = item.vis.node {
+            if !cx.access_levels.is_exported(item.hir_id()) {
+                if let Some(false) = self.is_exported.last() {
+                    let span = item.span.with_hi(item.ident.span.hi());
+                    let descr = cx.tcx.def_kind(item.def_id).descr(item.def_id.to_def_id());
+                    span_lint_and_then(
+                        cx,
+                        REDUNDANT_PUB_CRATE,
+                        span,
+                        &format!("pub(crate) {} inside private module", descr),
+                        |diag| {
+                            diag.span_suggestion(
+                                item.vis.span,
+                                "consider using",
+                                "pub".to_string(),
+                                Applicability::MachineApplicable,
+                            );
+                        },
+                    )
+                }
+            }
+        }
+
+        if let ItemKind::Mod { .. } = item.kind {
+            self.is_exported.push(cx.access_levels.is_exported(item.hir_id()));
+        }
+    }
+
+    fn check_item_post(&mut self, _cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
+        if let ItemKind::Mod { .. } = item.kind {
+            self.is_exported.pop().expect("unbalanced check_item/check_item_post");
+        }
+    }
+}