Rollup merge of #40814 - abonander:issue_39436, r=jseyfried

Rustdoc: memoize `pub use`-reexported macros so they don't appear twice in docs

Closes #39436

Preserves existing behavior for `#[macro_reexport]`. `pub use`'d macros are shown as reexports unless inlined, and also correctly obey `#[doc(hidden)]`.

r? @jseyfried

cc @SergioBenitez

3 files changed, 81 insertions, 2 deletions

diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index 27933076978..c89ec5bbe15 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -21,7 +21,7 @@ use syntax_pos::Span;
 
 use rustc::hir::map as hir_map;
 use rustc::hir::def::Def;
-use rustc::hir::def_id::LOCAL_CRATE;
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::middle::cstore::LoadedMacro;
 use rustc::middle::privacy::AccessLevel;
 use rustc::util::nodemap::FxHashSet;
@@ -48,6 +48,7 @@ pub struct RustdocVisitor<'a, 'tcx: 'a> {
     inlining: bool,
     /// Is the current module and all of its parents public?
     inside_public_path: bool,
+    reexported_macros: FxHashSet<DefId>,
 }
 
 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
@@ -62,6 +63,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             view_item_stack: stack,
             inlining: false,
             inside_public_path: true,
+            reexported_macros: FxHashSet(),
         }
     }
 
@@ -201,9 +203,10 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         if let Some(exports) = self.cx.tcx.export_map.get(&id) {
             for export in exports {
                 if let Def::Macro(def_id, ..) = export.def {
-                    if def_id.krate == LOCAL_CRATE {
+                    if def_id.krate == LOCAL_CRATE || self.reexported_macros.contains(&def_id) {
                         continue // These are `krate.exported_macros`, handled in `self.visit()`.
                     }
+
                     let imported_from = self.cx.sess().cstore.original_crate_name(def_id.krate);
                     let def = match self.cx.sess().cstore.load_macro(def_id, self.cx.sess()) {
                         LoadedMacro::MacroDef(macro_def) => macro_def,
@@ -217,6 +220,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                     } else {
                         unreachable!()
                     };
+
                     om.macros.push(Macro {
                         def_id: def_id,
                         attrs: def.attrs.clone().into(),
@@ -263,6 +267,8 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             false
         }
 
+        debug!("maybe_inline_local def: {:?}", def);
+
         let tcx = self.cx.tcx;
         if def == Def::Err {
             return false;
@@ -274,6 +280,17 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         let is_no_inline = use_attrs.lists("doc").has_word("no_inline") ||
                            use_attrs.lists("doc").has_word("hidden");
 
+        // Memoize the non-inlined `pub use`'d macros so we don't push an extra
+        // declaration in `visit_mod_contents()`
+        if !def_did.is_local() {
+            if let Def::Macro(did, _) = def {
+                if please_inline { return true }
+                debug!("memoizing non-inlined macro export: {:?}", def);
+                self.reexported_macros.insert(did);
+                return false;
+            }
+        }
+
         // For cross-crate impl inlining we need to know whether items are
         // reachable in documentation - a previously nonreachable item can be
         // made reachable by cross-crate inlining which we're checking here.
@@ -294,6 +311,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 },
                 _ => {},
             }
+
             return false
         }
 
diff --git a/src/test/rustdoc/auxiliary/pub-use-extern-macros.rs b/src/test/rustdoc/auxiliary/pub-use-extern-macros.rs
new file mode 100644
index 00000000000..70d174a149d
--- /dev/null
+++ b/src/test/rustdoc/auxiliary/pub-use-extern-macros.rs
@@ -0,0 +1,30 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+#![crate_name="macros"]
+
+#[macro_export]
+macro_rules! foo {
+    () => {};
+}
+
+#[macro_export]
+macro_rules! bar {
+    () => {};
+}
+
+#[macro_export]
+macro_rules! baz {
+    () => {};
+}
+
+#[macro_export]
+macro_rules! quux {
+    () => {};
+}
diff --git a/src/test/rustdoc/pub-use-extern-macros.rs b/src/test/rustdoc/pub-use-extern-macros.rs
new file mode 100644
index 00000000000..3f8f6f9544e
--- /dev/null
+++ b/src/test/rustdoc/pub-use-extern-macros.rs
@@ -0,0 +1,31 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:pub-use-extern-macros.rs
+
+#![feature(use_extern_macros, macro_reexport)]
+
+// @has pub_use_extern_macros/macro.foo.html
+// @!has pub_use_extern_macros/index.html 'pub use macros::foo;'
+#[macro_reexport(foo)] extern crate macros;
+
+// @has pub_use_extern_macros/index.html 'pub use macros::bar;'
+// @!has pub_use_extern_macros/macro.bar.html
+pub use macros::bar;
+
+// @has pub_use_extern_macros/macro.baz.html
+// @!has pub_use_extern_macros/index.html 'pub use macros::baz;'
+#[doc(inline)]
+pub use macros::baz;
+
+// @!has pub_use_extern_macros/macro.quux.html
+// @!has pub_use_extern_macros/index.html 'pub use macros::quux;'
+#[doc(hidden)]
+pub use macros::quux;