Auto merge of #113374 - GuillaumeGomez:private-to-public-path, r=notriddle,fmease

[rustdoc] If re-export is private, get the next item until a public one is found or expose the private item directly

Fixes #81141.

If we have:

```rust
use Private as Something;

pub fn foo() -> Something {}
```

Then `Something` will be replaced by `Private`.

r? `@notriddle`

7 files changed, 212 insertions, 0 deletions

diff --git a/tests/rustdoc/auxiliary/jump-to-def-res-err-handling-aux.rs b/tests/rustdoc/auxiliary/jump-to-def-res-err-handling-aux.rs
new file mode 100644
index 00000000000..eacec957a2a
--- /dev/null
+++ b/tests/rustdoc/auxiliary/jump-to-def-res-err-handling-aux.rs
@@ -0,0 +1 @@
+pub struct Ident;
diff --git a/tests/rustdoc/issue-81141-private-reexport-in-public-api-2.rs b/tests/rustdoc/issue-81141-private-reexport-in-public-api-2.rs
new file mode 100644
index 00000000000..4e9d188bbf8
--- /dev/null
+++ b/tests/rustdoc/issue-81141-private-reexport-in-public-api-2.rs
@@ -0,0 +1,13 @@
+// edition:2015
+
+#![crate_name = "foo"]
+
+use external::Public as Private;
+
+pub mod external {
+    pub struct Public;
+
+    // @has 'foo/external/fn.make.html'
+    // @has - '//*[@class="rust item-decl"]/code' 'pub fn make() -> Public'
+    pub fn make() -> ::Private { super::Private }
+}
diff --git a/tests/rustdoc/issue-81141-private-reexport-in-public-api-generics.rs b/tests/rustdoc/issue-81141-private-reexport-in-public-api-generics.rs
new file mode 100644
index 00000000000..7e289508628
--- /dev/null
+++ b/tests/rustdoc/issue-81141-private-reexport-in-public-api-generics.rs
@@ -0,0 +1,13 @@
+#![crate_name = "foo"]
+
+use crate::bar::Foo as Alias;
+
+pub mod bar {
+    pub struct Foo<'a, T>(&'a T);
+}
+
+// @has "foo/fn.foo.html"
+// @has - '//*[@class="rust item-decl"]/code' "pub fn foo<'a, T>(f: Foo<'a, T>) -> Foo<'a, usize>"
+pub fn foo<'a, T>(f: Alias<'a, T>) -> Alias<'a, usize> {
+    Alias(&0)
+}
diff --git a/tests/rustdoc/issue-81141-private-reexport-in-public-api-hidden.rs b/tests/rustdoc/issue-81141-private-reexport-in-public-api-hidden.rs
new file mode 100644
index 00000000000..5053a328bad
--- /dev/null
+++ b/tests/rustdoc/issue-81141-private-reexport-in-public-api-hidden.rs
@@ -0,0 +1,16 @@
+// compile-flags: -Z unstable-options --document-hidden-items
+
+#![crate_name = "foo"]
+
+#[doc(hidden)]
+pub use crate::bar::Bar as Alias;
+
+mod bar {
+    pub struct Bar;
+}
+
+// @has 'foo/fn.bar.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar() -> Alias'
+pub fn bar() -> Alias {
+    Alias
+}
diff --git a/tests/rustdoc/issue-81141-private-reexport-in-public-api-private.rs b/tests/rustdoc/issue-81141-private-reexport-in-public-api-private.rs
new file mode 100644
index 00000000000..15749674a3d
--- /dev/null
+++ b/tests/rustdoc/issue-81141-private-reexport-in-public-api-private.rs
@@ -0,0 +1,32 @@
+// compile-flags: --document-private-items
+
+#![crate_name = "foo"]
+
+use crate::bar::Bar as Alias;
+pub(crate) use crate::bar::Bar as CrateAlias;
+
+mod bar {
+    pub struct Bar;
+    pub use self::Bar as Inner;
+}
+
+// It's a fully private re-export so it should not be displayed.
+// @has 'foo/fn.bar.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar() -> Bar'
+pub fn bar() -> Alias {
+    Alias
+}
+
+// It's public re-export inside a private module so it should be visible.
+// @has 'foo/fn.bar2.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar2() -> Inner'
+pub fn bar2() -> crate::bar::Inner {
+    Alias
+}
+
+// It's a non-public, so it doesn't appear in documentation so it should not be visible.
+// @has 'foo/fn.bar3.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar3() -> Bar'
+pub fn bar3() -> CrateAlias {
+    Alias
+}
diff --git a/tests/rustdoc/issue-81141-private-reexport-in-public-api.rs b/tests/rustdoc/issue-81141-private-reexport-in-public-api.rs
new file mode 100644
index 00000000000..bd54d02c6ec
--- /dev/null
+++ b/tests/rustdoc/issue-81141-private-reexport-in-public-api.rs
@@ -0,0 +1,124 @@
+// This test ensures that if a private re-export is present in a public API, it'll be
+// replaced by the first public item in the re-export chain or by the private item.
+
+#![crate_name = "foo"]
+
+use crate::bar::Bar as Alias;
+
+pub use crate::bar::Bar as Whatever;
+use crate::Whatever as Whatever2;
+use crate::Whatever2 as Whatever3;
+pub use crate::bar::Inner as Whatever4;
+
+mod bar {
+    pub struct Bar;
+    pub use self::Bar as Inner;
+}
+
+// @has 'foo/fn.bar.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar() -> Bar'
+pub fn bar() -> Alias {
+    Alias
+}
+
+// @has 'foo/fn.bar2.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar2() -> Whatever'
+pub fn bar2() -> Whatever3 {
+    Whatever
+}
+
+// @has 'foo/fn.bar3.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar3() -> Whatever4'
+pub fn bar3() -> Whatever4 {
+    Whatever
+}
+
+// @has 'foo/fn.bar4.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar4() -> Bar'
+pub fn bar4() -> crate::Alias {
+    Alias
+}
+
+// @has 'foo/fn.bar5.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar5() -> Whatever'
+pub fn bar5() -> crate::Whatever3 {
+    Whatever
+}
+
+// @has 'foo/fn.bar6.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar6() -> Whatever4'
+pub fn bar6() -> crate::Whatever4 {
+    Whatever
+}
+
+
+// @has 'foo/fn.bar7.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar7() -> Bar'
+pub fn bar7() -> self::Alias {
+    Alias
+}
+
+// @has 'foo/fn.bar8.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar8() -> Whatever'
+pub fn bar8() -> self::Whatever3 {
+    Whatever
+}
+
+// @has 'foo/fn.bar9.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar9() -> Whatever4'
+pub fn bar9() -> self::Whatever4 {
+    Whatever
+}
+
+mod nested {
+    pub(crate) use crate::Alias;
+    pub(crate) use crate::Whatever3;
+    pub(crate) use crate::Whatever4;
+    pub(crate) use crate::nested as nested2;
+}
+
+// @has 'foo/fn.bar10.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar10() -> Bar'
+pub fn bar10() -> nested::Alias {
+    Alias
+}
+
+// @has 'foo/fn.bar11.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar11() -> Whatever'
+pub fn bar11() -> nested::Whatever3 {
+    Whatever
+}
+
+// @has 'foo/fn.bar12.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar12() -> Whatever4'
+pub fn bar12() -> nested::Whatever4 {
+    Whatever
+}
+
+// @has 'foo/fn.bar13.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar13() -> Bar'
+pub fn bar13() -> nested::nested2::Alias {
+    Alias
+}
+
+// @has 'foo/fn.bar14.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar14() -> Whatever'
+pub fn bar14() -> nested::nested2::Whatever3 {
+    Whatever
+}
+
+// @has 'foo/fn.bar15.html'
+// @has - '//*[@class="rust item-decl"]/code' 'pub fn bar15() -> Whatever4'
+pub fn bar15() -> nested::nested2::Whatever4 {
+    Whatever
+}
+
+use external::Public as Private;
+
+pub mod external {
+    pub struct Public;
+
+    // @has 'foo/external/fn.make.html'
+    // @has - '//*[@class="rust item-decl"]/code' 'pub fn make() -> Public'
+    pub fn make() -> super::Private { super::Private }
+}
diff --git a/tests/rustdoc/private-use.rs b/tests/rustdoc/private-use.rs
new file mode 100644
index 00000000000..689ed73140d
--- /dev/null
+++ b/tests/rustdoc/private-use.rs
@@ -0,0 +1,13 @@
+// Regression test for <https://github.com/rust-lang/rust/pull/113374> to
+// ensure it doesn't panic.
+
+mod generics {
+    pub enum WherePredicate {
+        EqPredicate,
+    }
+}
+pub mod visit {
+    use *;
+    pub fn visit_where_predicate<V>(_visitor: &mut V, _i: &WherePredicate) {}
+}
+pub use generics::*;