Add regression test for rust-lang#46506

tests/rustdoc/issue-46506-pub-reexport-of-pub-reexport.rs

@@ -0,0 +1,24 @@
+// This is a regression test for <https://github.com/rust-lang/rust/issues/46506>.
+// This test ensures that if public re-exported is re-exported, it won't be inlined.
+
+#![crate_name = "foo"]
+
+// @has 'foo/associations/index.html'
+// @count - '//*[@id="main-content"]/*[@class="small-section-header"]' 1
+// @has - '//*[@id="main-content"]/*[@class="small-section-header"]' 'Traits'
+// @has - '//*[@id="main-content"]//a[@href="trait.GroupedBy.html"]' 'GroupedBy'
+// @has 'foo/associations/trait.GroupedBy.html'
+pub mod associations {
+    mod belongs_to {
+        pub trait GroupedBy {}
+    }
+    pub use self::belongs_to::GroupedBy;
+}
+
+// @has 'foo/prelude/index.html'
+// @count - '//*[@id="main-content"]/*[@class="small-section-header"]' 1
+// @has - '//*[@id="main-content"]/*[@class="small-section-header"]' 'Re-exports'
+// @has - '//*[@id="main-content"]//*[@id="reexport.GroupedBy"]' 'pub use associations::GroupedBy;'
+pub mod prelude {
+    pub use associations::GroupedBy;
+}