Auto merge of rust-lang#76571 - lzutao:rustdoc-private-traits, r=jyn514

Ignore rustc_private items from std docs

By ignoring rustc_private items for non local impl block,
this may fix rust-lang#74672 and fix rust-lang#75588 .

This might suppress rust-lang#76529 if it is simple enough for backport.

Author: bors

src/librustdoc/clean/inline.rs

@@ -337,18 +337,13 @@ pub fn build_impl(
     // reachable in rustdoc generated documentation
     if !did.is_local() {
         if let Some(traitref) = associated_trait {
-            if !cx.renderinfo.borrow().access_levels.is_public(traitref.def_id) {
+            let did = traitref.def_id;
+            if !cx.renderinfo.borrow().access_levels.is_public(did) {
                 return;
             }
-        }
 
-        // Skip foreign unstable traits from lists of trait implementations and
-        // such. This helps prevent dependencies of the standard library, for
-        // example, from getting documented as "traits `u32` implements" which
-        // isn't really too helpful.
-        if let Some(trait_did) = associated_trait {
-            if let Some(stab) = cx.tcx.lookup_stability(trait_did.def_id) {
-                if stab.level.is_unstable() {
+            if let Some(stab) = tcx.lookup_stability(did) {
+                if stab.level.is_unstable() && stab.feature == sym::rustc_private {
                     return;
                 }
             }
@@ -372,6 +367,12 @@ pub fn build_impl(
             if !cx.renderinfo.borrow().access_levels.is_public(did) {
                 return;
             }
+
+            if let Some(stab) = tcx.lookup_stability(did) {
+                if stab.level.is_unstable() && stab.feature == sym::rustc_private {
+                    return;
+                }
+            }
         }
     }
 

src/test/rustdoc/auxiliary/real_gimli.rs

@@ -0,0 +1,13 @@
+// aux-build:realcore.rs
+
+#![crate_name = "real_gimli"]
+#![feature(staged_api, extremely_unstable)]
+#![unstable(feature = "rustc_private", issue = "none")]
+
+extern crate realcore;
+
+#[unstable(feature = "rustc_private", issue = "none")]
+pub struct EndianSlice;
+
+#[unstable(feature = "rustc_private", issue = "none")]
+impl realcore::Deref for EndianSlice {}

src/test/rustdoc/auxiliary/realcore.rs

@@ -0,0 +1,15 @@
+#![crate_name = "realcore"]
+#![feature(staged_api)]
+#![unstable(feature = "extremely_unstable", issue = "none")]
+
+#[unstable(feature = "extremely_unstable_foo", issue = "none")]
+pub struct Foo {}
+
+#[unstable(feature = "extremely_unstable_foo", issue = "none")]
+pub trait Join {}
+
+#[unstable(feature = "extremely_unstable_foo", issue = "none")]
+impl Join for Foo {}
+
+#[stable(feature = "faked_deref", since = "1.47.0")]
+pub trait Deref {}

src/test/rustdoc/issue-75588.rs

@@ -0,0 +1,18 @@
+// ignore-tidy-linelength
+// aux-build:realcore.rs
+// aux-build:real_gimli.rs
+
+// Ensure unstably exported traits have their Implementors sections.
+
+#![crate_name = "foo"]
+#![feature(extremely_unstable_foo)]
+
+extern crate realcore;
+extern crate real_gimli;
+
+// issue #74672
+// @!has foo/trait.Deref.html '//*[@id="impl-Deref-for-EndianSlice"]//code' 'impl Deref for EndianSlice'
+pub use realcore::Deref;
+
+// @has foo/trait.Join.html '//*[@id="impl-Join-for-Foo"]//code' 'impl Join for Foo'
+pub use realcore::Join;

src/tools/linkchecker/main.rs

@@ -142,6 +142,16 @@ fn is_exception(file: &Path, link: &str) -> bool {
     if let Some(entry) = LINKCHECK_EXCEPTIONS.iter().find(|&(f, _)| file.ends_with(f)) {
         entry.1.contains(&link)
     } else {
+        // FIXME(#63351): Concat trait in alloc/slice reexported in primitive page
+        //
+        // NOTE: This cannot be added to `LINKCHECK_EXCEPTIONS` because the resolved path
+        // calculated in `check` function is outside `build/<triple>/doc` dir.
+        // So the `strip_prefix` method just returns the old absolute broken path.
+        if file.ends_with("std/primitive.slice.html") {
+            if link.ends_with("primitive.slice.html") {
+                return true;
+            }
+        }
         false
     }
 }