Fix unreachable_pub suggestion for enum with fields

compiler/rustc_lint/src/builtin.rs

@@ -40,7 +40,7 @@ use rustc_feature::{deprecated_attributes, AttributeGate, BuiltinAttribute, Gate
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalDefIdSet, CRATE_DEF_ID};
-use rustc_hir::{ForeignItemKind, GenericParamKind, HirId, PatKind, PredicateOrigin};
+use rustc_hir::{ForeignItemKind, GenericParamKind, HirId, Node, PatKind, PredicateOrigin};
 use rustc_index::vec::Idx;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::layout::{LayoutError, LayoutOf};
@@ -1430,7 +1430,11 @@ impl<'tcx> LateLintPass<'tcx> for UnreachablePub {
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) {
-        let def_id = cx.tcx.hir().local_def_id(field.hir_id);
+        let map = cx.tcx.hir();
+        let def_id = map.local_def_id(field.hir_id);
+        if matches!(map.get(map.get_parent_node(field.hir_id)), Node::Variant(_)) {
+            return;
+        }
         self.perform_lint(cx, "field", def_id, field.vis_span, false);
     }
 

src/test/ui/lint/issue-103317.rs

@@ -0,0 +1,13 @@
+// check-pass
+
+#[warn(unreachable_pub)]
+#[allow(unused)]
+mod inner {
+    pub enum T {
+        //~^ WARN unreachable `pub` item
+        A(u8),
+        X { a: f32, b: () },
+    }
+}
+
+fn main() {}

src/test/ui/lint/issue-103317.stderr

@@ -0,0 +1,17 @@
+warning: unreachable `pub` item
+  --> $DIR/issue-103317.rs:6:5
+   |
+LL |     pub enum T {
+   |     ---^^^^^^^
+   |     |
+   |     help: consider restricting its visibility: `pub(crate)`
+   |
+   = help: or consider exporting it for use by other crates
+note: the lint level is defined here
+  --> $DIR/issue-103317.rs:3:8
+   |
+LL | #[warn(unreachable_pub)]
+   |        ^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+