Rollup merge of #51011 - QuietMisdreavus:duplicitous-macros, r=ollie27

 rustdoc: hide macro export statements from docs

As mentioned in https://github.com/rust-lang/rust/issues/50647, rustdoc now prints both the import statement and the macro itself when re-exporting macros. This is a stopgap solution to clean up the std docs and get something small backported into beta.

What this does: When rustdoc finds an export statement for a macro, instead of printing the export and bailing, now it will instead hide the export and bail. Until we can solve https://github.com/rust-lang/rust/issues/34843 or have a better way to find the attributes on an export statement when inlining macros, this will at least match the current behavior and clean up the re-export statements from the docs.

src/librustdoc/clean/inline.rs

@@ -97,6 +97,9 @@ pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name, visited: &mut FxHa
             record_extern_fqn(cx, did, clean::TypeKind::Const);
             clean::ConstantItem(build_const(cx, did))
         }
+        // Macros are eagerly inlined back in visit_ast, don't show their export statements
+        // FIXME(50647): the eager inline does not take doc(hidden)/doc(no_inline) into account
+        Def::Macro(..) => return Some(Vec::new()),
         _ => return None,
     };
     cx.renderinfo.borrow_mut().inlined.insert(did);

src/librustdoc/visit_ast.rs

@@ -219,6 +219,8 @@ pub fn visit_mod_contents(&mut self, span: Span, attrs: hir::HirVec<ast::Attribu
         if let Some(exports) = self.cx.tcx.module_exports(def_id) {
             for export in exports.iter().filter(|e| e.vis == Visibility::Public) {
                 if let Def::Macro(def_id, ..) = export.def {
+                    // FIXME(50647): this eager macro inlining does not take
+                    // doc(hidden)/doc(no_inline) into account
                     if def_id.krate == LOCAL_CRATE {
                         continue // These are `krate.exported_macros`, handled in `self.visit()`.
                     }
@@ -237,6 +239,7 @@ pub fn visit_mod_contents(&mut self, span: Span, attrs: hir::HirVec<ast::Attribu
                         unreachable!()
                     };
 
+                    debug!("inlining macro {}", def.ident.name);
                     om.macros.push(Macro {
                         def_id,
                         attrs: def.attrs.clone().into(),
@@ -561,6 +564,7 @@ pub fn visit_item(&mut self, item: &hir::Item,
 
     // convert each exported_macro into a doc item
     fn visit_local_macro(&self, def: &hir::MacroDef) -> Macro {
+        debug!("visit_local_macro: {}", def.name);
         let tts = def.body.trees().collect::<Vec<_>>();
         // Extract the spans of all matchers. They represent the "interface" of the macro.
         let matchers = tts.chunks(4).map(|arm| arm[0].span()).collect();

src/test/rustdoc/pub-use-extern-macros.rs

@@ -15,14 +15,15 @@
 extern crate macros;
 
 // @has pub_use_extern_macros/macro.bar.html
+// @!has pub_use_extern_macros/index.html '//code' 'pub use macros::bar;'
 pub use macros::bar;
 
 // @has pub_use_extern_macros/macro.baz.html
-// @!has pub_use_extern_macros/index.html 'pub use macros::baz;'
+// @!has pub_use_extern_macros/index.html '//code' '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;'
+// @!has pub_use_extern_macros/index.html '//code' 'pub use macros::quux;'
 #[doc(hidden)]
 pub use macros::quux;