Rollup merge of rust-lang#143849 - lolbinarycat:rustdoc-priv-normalize-143222, r=GuillaumeGomez

rustdoc: never link to unnamable items

fixes rust-lang#143222

Author: jhpratt

src/librustdoc/html/format.rs

@@ -368,6 +368,8 @@ pub(crate) enum HrefError {
     Private,
     // Not in external cache, href link should be in same page
     NotInExternalCache,
+    /// Refers to an unnamable item, such as one defined within a function or const block.
+    UnnamableItem,
 }
 
 /// This function is to get the external macro path because they are not in the cache used in
@@ -479,6 +481,26 @@ fn generate_item_def_id_path(
     Ok((url_parts, shortty, fqp))
 }
 
+/// Checks if the given defid refers to an item that is unnamable, such as one defined in a const block.
+fn is_unnamable(tcx: TyCtxt<'_>, did: DefId) -> bool {
+    let mut cur_did = did;
+    while let Some(parent) = tcx.opt_parent(cur_did) {
+        match tcx.def_kind(parent) {
+            // items defined in these can be linked to, as long as they are visible
+            DefKind::Mod | DefKind::ForeignMod => cur_did = parent,
+            // items in impls can be linked to,
+            // as long as we can link to the item the impl is on.
+            // since associated traits are not a thing,
+            // it should not be possible to refer to an impl item if
+            // the base type is not namable.
+            DefKind::Impl { .. } => return false,
+            // everything else does not have docs generated for it
+            _ => return true,
+        }
+    }
+    return false;
+}
+
 fn to_module_fqp(shortty: ItemType, fqp: &[Symbol]) -> &[Symbol] {
     if shortty == ItemType::Module { fqp } else { &fqp[..fqp.len() - 1] }
 }
@@ -552,6 +574,9 @@ pub(crate) fn href_with_root_path(
         }
         _ => original_did,
     };
+    if is_unnamable(cx.tcx(), did) {
+        return Err(HrefError::UnnamableItem);
+    }
     let cache = cx.cache();
     let relative_to = &cx.current;
 

tests/rustdoc/reexport/auxiliary/wrap-unnamable-type.rs

@@ -0,0 +1,12 @@
+pub trait Assoc {
+    type Ty;
+}
+
+pub struct Foo(<Foo as crate::Assoc>::Ty);
+
+const _X: () = {
+    impl crate::Assoc for Foo {
+        type Ty = Bar;
+    }
+    pub struct Bar;
+};

tests/rustdoc/reexport/wrapped-unnamble-type-143222.rs

@@ -0,0 +1,16 @@
+//@ compile-flags: -Z normalize-docs --document-private-items -Zunstable-options --show-type-layout
+//@ aux-build:wrap-unnamable-type.rs
+//@ build-aux-docs
+
+// regression test for https://github.com/rust-lang/rust/issues/143222
+// makes sure normalizing docs does not cause us to link to unnamable types
+// in cross-crate reexports.
+
+#![crate_name = "foo"]
+
+extern crate wrap_unnamable_type as helper;
+
+//@ has 'foo/struct.Foo.html'
+//@ !hasraw - 'struct.Bar.html'
+#[doc(inline)]
+pub use helper::Foo;