From 2f71ce665178b08b5bea3a3e8401c75e67d57e51 Mon Sep 17 00:00:00 2001
From: y21 <30553356+y21@users.noreply.github.com>
Date: Sun, 20 Oct 2024 22:14:02 +0200
Subject: [PATCH 1/2] don't lint unnamed constants in
 `missing_docs_in_private_items`

---
 clippy_lints/src/missing_doc.rs | 9 +++++++--
 tests/ui/missing_doc.rs         | 3 +++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/missing_doc.rs b/clippy_lints/src/missing_doc.rs
index ce508d85d634..cff27681c95c 100644
--- a/clippy_lints/src/missing_doc.rs
+++ b/clippy_lints/src/missing_doc.rs
@@ -17,6 +17,7 @@ use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::ty::Visibility;
 use rustc_session::impl_lint_pass;
 use rustc_span::def_id::CRATE_DEF_ID;
+use rustc_span::symbol::kw;
 use rustc_span::{Span, sym};
 
 declare_clippy_lint! {
@@ -184,8 +185,12 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
                     }
                 }
             },
-            hir::ItemKind::Const(..)
-            | hir::ItemKind::Enum(..)
+            hir::ItemKind::Const(..) => {
+                if it.ident.name == kw::Underscore {
+                    note_prev_span_then_ret!(self.prev_span, it.span);
+                }
+            },
+            hir::ItemKind::Enum(..)
             | hir::ItemKind::Macro(..)
             | hir::ItemKind::Mod(..)
             | hir::ItemKind::Static(..)
diff --git a/tests/ui/missing_doc.rs b/tests/ui/missing_doc.rs
index 9c936d7fa23e..a8fcbefcc0e5 100644
--- a/tests/ui/missing_doc.rs
+++ b/tests/ui/missing_doc.rs
@@ -116,6 +116,9 @@ with_span!(span pub fn foo_pm() {});
 with_span!(span pub static FOO_PM: u32 = 0;);
 with_span!(span pub const FOO2_PM: u32 = 0;);
 
+// Don't lint unnamed constants
+const _: () = ();
+
 // issue #12197
 // Undocumented field originated inside of spanned proc-macro attribute
 /// Some dox for struct.

From b3bf128e545213b8e101b9584acc84de9ece22d8 Mon Sep 17 00:00:00 2001
From: y21 <30553356+y21@users.noreply.github.com>
Date: Sun, 20 Oct 2024 23:42:28 +0200
Subject: [PATCH 2/2] don't lint nested items that don't have generated
 documentation in `missing_docs_in_private_items`

---
 clippy_lints/src/missing_doc.rs | 16 ++++++++++++++++
 tests/ui/missing_doc.rs         |  5 +++++
 tests/ui/missing_doc.stderr     | 11 ++++++++++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/clippy_lints/src/missing_doc.rs b/clippy_lints/src/missing_doc.rs
index cff27681c95c..1300c7d10628 100644
--- a/clippy_lints/src/missing_doc.rs
+++ b/clippy_lints/src/missing_doc.rs
@@ -12,6 +12,7 @@ use clippy_utils::is_from_proc_macro;
 use clippy_utils::source::SpanRangeExt;
 use rustc_ast::ast::{self, MetaItem, MetaItemKind};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::ty::Visibility;
@@ -111,6 +112,21 @@ impl MissingDoc {
             return;
         }
 
+        if let Some(parent_def_id) = cx.tcx.opt_parent(def_id.to_def_id())
+            && let DefKind::AnonConst
+            | DefKind::AssocConst
+            | DefKind::AssocFn
+            | DefKind::Closure
+            | DefKind::Const
+            | DefKind::Fn
+            | DefKind::InlineConst
+            | DefKind::Static { .. }
+            | DefKind::SyntheticCoroutineBody = cx.tcx.def_kind(parent_def_id)
+        {
+            // Nested item has no generated documentation, so it doesn't need to be documented.
+            return;
+        }
+
         let has_doc = attrs
             .iter()
             .any(|a| a.doc_str().is_some() || Self::has_include(a.meta()))
diff --git a/tests/ui/missing_doc.rs b/tests/ui/missing_doc.rs
index a8fcbefcc0e5..31bc4309582e 100644
--- a/tests/ui/missing_doc.rs
+++ b/tests/ui/missing_doc.rs
@@ -119,6 +119,11 @@ with_span!(span pub const FOO2_PM: u32 = 0;);
 // Don't lint unnamed constants
 const _: () = ();
 
+fn issue13298() {
+    // Rustdoc doesn't generate documentation for items within other items like fns or consts
+    const MSG: &str = "Hello, world!";
+}
+
 // issue #12197
 // Undocumented field originated inside of spanned proc-macro attribute
 /// Some dox for struct.
diff --git a/tests/ui/missing_doc.stderr b/tests/ui/missing_doc.stderr
index ef0f96a5b713..133c76ac9d43 100644
--- a/tests/ui/missing_doc.stderr
+++ b/tests/ui/missing_doc.stderr
@@ -88,5 +88,14 @@ error: missing documentation for a function
 LL |         fn also_undocumented2() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 13 previous errors
+error: missing documentation for a function
+  --> tests/ui/missing_doc.rs:122:1
+   |
+LL | / fn issue13298() {
+LL | |     // Rustdoc doesn't generate documentation for items within other items like fns or consts
+LL | |     const MSG: &str = "Hello, world!";
+LL | | }
+   | |_^
+
+error: aborting due to 14 previous errors