Auto merge of #86322 - trinity-1686a:rustdoc-fix-overflow-recursive-deref, r=jyn514

fix rustdoc stack overflow on mutually recursive Deref

fix #85095
fix #85037

src/test/rustdoc/recursive-deref-sidebar.rs

@@ -0,0 +1,22 @@
+use std::ops::Deref;
+
+pub struct A {}
+impl A { pub fn foo_a(&self) {} }
+
+pub struct B {}
+impl B { pub fn foo_b(&self) {} }
+
+pub struct C {}
+impl C { pub fn foo_c(&self) {} }
+
+// @has recursive_deref_sidebar/struct.A.html '//div[@class="sidebar-links"]' 'foo_b'
+impl Deref for A {
+    type Target = B;
+    fn deref(&self) -> &B { todo!() }
+}
+
+// @!has recursive_deref_sidebar/struct.A.html '//div[@class="sidebar-links"]' 'foo_c'
+impl Deref for B {
+    type Target = C;
+    fn deref(&self) -> &C { todo!() }
+}

src/test/rustdoc/recursive-deref.rs

@@ -0,0 +1,22 @@
+use std::ops::Deref;
+
+pub struct A;
+pub struct B;
+
+// @has recursive_deref/struct.A.html '//code' 'impl Deref for A'
+impl Deref for A {
+    type Target = B;
+
+    fn deref(&self) -> &Self::Target {
+        panic!()
+    }
+}
+
+// @has recursive_deref/struct.B.html '//code' 'impl Deref for B'
+impl Deref for B {
+    type Target = A;
+
+    fn deref(&self) -> &Self::Target {
+        panic!()
+    }
+}