rustdoc: don't mark Box<T> as Iterator, Read, etc

src/librustdoc/html/render/mod.rs

@@ -1276,6 +1276,15 @@ fn notable_traits_decl(decl: &clean::FnDecl, cx: &Context<'_>) -> String {
 
  if let Some((did, ty)) = decl.output.as_return().and_then(|t| Some((t.def_id(cx.cache())?, t)))
  {
+ // Box has pass-through impls for Read, Write, Iterator, and Future when the
+ // boxed type implements one of those. We don't want to treat every Box return
+ // as being notably an Iterator (etc), though, so we exempt it. Pin has the same
+ // issue, with a pass-through impl for Future.
+ if Some(did) == cx.tcx().lang_items().owned_box()
+ || Some(did) == cx.tcx().lang_items().pin_type()
+ {
+ return "".to_string();
+ }
  if let Some(impls) = cx.cache().impls.get(&did) {
  for i in impls {
  let impl_ = i.inner_impl();

src/test/rustdoc/doc-notable_trait_box_is_not_an_iterator.rs

@@ -0,0 +1,38 @@
+#![feature(doc_notable_trait)]
+#![feature(lang_items)]
+#![feature(no_core)]
+#![no_core]
+#[lang = "owned_box"]
+pub struct Box<T>;
+
+impl<T> Box<T> {
+ pub fn new(x: T) -> Box<T> {
+ Box
+ }
+}
+
+#[doc(notable_trait)]
+pub trait FakeIterator {}
+
+impl<I: FakeIterator> FakeIterator for Box<I> {}
+
+#[lang = "pin"]
+pub struct Pin<T>;
+
+impl<T> Pin<T> {
+ pub fn new(x: T) -> Pin<T> {
+ Pin
+ }
+}
+
+impl<I: FakeIterator> FakeIterator for Pin<I> {}
+
+// @!has doc_notable_trait_box_is_not_an_iterator/fn.foo.html '//*' 'Notable'
+pub fn foo<T>(x: T) -> Box<T> {
+ Box::new(x)
+}
+
+// @!has doc_notable_trait_box_is_not_an_iterator/fn.bar.html '//*' 'Notable'
+pub fn bar<T>(x: T) -> Pin<T> {
+ Pin::new(x)
+}