Add regression test for rust-lang#111415

tests/rustdoc/nested-items-issue-111415.rs

@@ -0,0 +1,36 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/111415>.
+// This test ensures that only impl blocks are documented in bodies.
+
+#![crate_name = "foo"]
+
+// @has 'foo/index.html'
+// Checking there are only three sections.
+// @count - '//*[@id="main-content"]/*[@class="small-section-header"]' 3
+// @has - '//*[@id="main-content"]/*[@class="small-section-header"]' 'Structs'
+// @has - '//*[@id="main-content"]/*[@class="small-section-header"]' 'Functions'
+// @has - '//*[@id="main-content"]/*[@class="small-section-header"]' 'Traits'
+// Checking that there are only three items.
+// @count - '//*[@id="main-content"]//*[@class="item-name"]' 3
+// @has - '//*[@id="main-content"]//a[@href="struct.Bar.html"]' 'Bar'
+// @has - '//*[@id="main-content"]//a[@href="fn.foo.html"]' 'foo'
+// @has - '//*[@id="main-content"]//a[@href="trait.Foo.html"]' 'Foo'
+
+// Now checking that the `foo` method is visible in `Bar` page.
+// @has 'foo/struct.Bar.html'
+// @has - '//*[@id="method.foo"]/*[@class="code-header"]' 'pub fn foo()'
+// @has - '//*[@id="method.bar"]/*[@class="code-header"]' 'fn bar()'
+pub struct Bar;
+
+pub trait Foo {
+    fn bar() {}
+}
+
+pub fn foo() {
+    pub mod inaccessible {}
+    pub fn inner() {}
+    pub const BAR: u32 = 0;
+    impl Bar {
+        pub fn foo() {}
+    }
+    impl Foo for Bar {}
+}