Add regression test for reexported macros docs

tests/rustdoc/reexport-macro.rs

@@ -0,0 +1,23 @@
+// Ensure that macros are correctly reexported and that they get both the comment from the
+// `pub use` and from the macro.
+
+#![crate_name = "foo"]
+
+// @has 'foo/macro.foo.html'
+// @!has - '//*[@class="toggle top-doc"]/*[@class="docblock"]' 'x y'
+// @has - '//*[@class="toggle top-doc"]/*[@class="docblock"]' 'y'
+#[macro_use]
+mod my_module {
+    /// y
+    #[macro_export]
+    macro_rules! foo {
+        () => ();
+    }
+}
+
+// @has 'foo/another_mod/macro.bar.html'
+// @has - '//*[@class="toggle top-doc"]/*[@class="docblock"]' 'x y'
+pub mod another_mod {
+    /// x
+    pub use crate::foo as bar;
+}