From 727baf0db196a6926e5ce755e73b5af5fd6ccf2a Mon Sep 17 00:00:00 2001
From: Joshua Nelson <jyn514@gmail.com>
Date: Tue, 30 Nov 2021 14:25:55 -0500
Subject: [PATCH] When documenting private items in a binary, ignore warnings
 about links to private items

Previously, rustdoc would warn about linking to items in a binary, even
though cargo unconditionally documents private items in a binary.
This changes cargo to silence the warning, since it's only relevant in
cases where the private items might not be documented.
---
 src/cargo/ops/cargo_compile.rs |  6 ++++++
 tests/testsuite/doc.rs         | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/src/cargo/ops/cargo_compile.rs b/src/cargo/ops/cargo_compile.rs
index 2a5d09f520b..4c5bee3b3fa 100644
--- a/src/cargo/ops/cargo_compile.rs
+++ b/src/cargo/ops/cargo_compile.rs
@@ -646,6 +646,12 @@ pub fn create_bcx<'a, 'cfg>(
             if rustdoc_document_private_items || unit.target.is_bin() {
                 let mut args = extra_args.take().unwrap_or_default();
                 args.push("--document-private-items".into());
+                if unit.target.is_bin() {
+                    // This warning only makes sense if it's possible to document private items
+                    // sometimes and ignore them at other times. But cargo consistently passes
+                    // `--document-private-items`, so the warning isn't useful.
+                    args.push("-Arustdoc::private-intra-doc-links".into());
+                }
                 extra_args = Some(args);
             }
 
diff --git a/tests/testsuite/doc.rs b/tests/testsuite/doc.rs
index dd6a3ec46ca..18882067bf9 100644
--- a/tests/testsuite/doc.rs
+++ b/tests/testsuite/doc.rs
@@ -2767,3 +2767,24 @@ fn doc_check_cfg_features() {
         )
         .run();
 }
+
+#[cargo_test]
+fn link_to_private_item() {
+    let main = r#"
+    //! [bar]
+    #[allow(dead_code)]
+    fn bar() {}
+    "#;
+    let p = project().file("src/lib.rs", main).build();
+    p.cargo("doc")
+        .with_stderr_contains("[..] documentation for `foo` links to private item `bar`")
+        .run();
+    // Check that binaries don't emit a private_intra_doc_links warning.
+    fs::rename(p.root().join("src/lib.rs"), p.root().join("src/main.rs")).unwrap();
+    p.cargo("doc")
+        .with_stderr(
+            "[DOCUMENTING] foo [..]\n\
+             [FINISHED] [..]",
+        )
+        .run();
+}