Rollup merge of #110279 - GuillaumeGomez:compiler-macro-derive, r=notriddle

rustdoc: Correctly handle built-in compiler proc-macros as proc-macro and not macro

Part of https://github.com/rust-lang/rust/issues/110111.

There were actually one issue split in two parts:
 * Compiler built-in proc-macro were incorrectly considered as macros and not proc-macros.
 * Re-exports of compiler built-in proc-macros were considering them as macros.

Both issues can be fixed by looking at the `MacroKind` variant instead of just relying on information extracted later on.

r? ``@fmease``

src/librustdoc/clean/inline.rs

@@ -111,7 +111,7 @@ pub(crate) fn try_inline(
             clean::ConstantItem(build_const(cx, did))
         }
         Res::Def(DefKind::Macro(kind), did) => {
-            let mac = build_macro(cx, did, name, import_def_id);
+            let mac = build_macro(cx, did, name, import_def_id, kind);
 
             let type_kind = match kind {
                 MacroKind::Bang => ItemType::Macro,
@@ -651,9 +651,11 @@ fn build_macro(
     def_id: DefId,
     name: Symbol,
     import_def_id: Option<DefId>,
+    macro_kind: MacroKind,
 ) -> clean::ItemKind {
     match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.sess()) {
-        LoadedMacro::MacroDef(item_def, _) => {
+        LoadedMacro::MacroDef(item_def, _) => match macro_kind {
+            MacroKind::Bang => {
                 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
                     let vis = cx.tcx.visibility(import_def_id.unwrap_or(def_id));
                     clean::MacroItem(clean::Macro {
@@ -663,6 +665,10 @@ fn build_macro(
                     unreachable!()
                 }
             }
+            MacroKind::Derive | MacroKind::Attr => {
+                clean::ProcMacroItem(clean::ProcMacro { kind: macro_kind, helpers: Vec::new() })
+            }
+        },
         LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
             kind: ext.macro_kind(),
             helpers: ext.helper_attrs,

src/librustdoc/clean/mod.rs

@@ -909,6 +909,38 @@ fn clean_ty_generics<'tcx>(
     }
 }
 
+fn clean_proc_macro<'tcx>(
+    item: &hir::Item<'tcx>,
+    name: &mut Symbol,
+    kind: MacroKind,
+    cx: &mut DocContext<'tcx>,
+) -> ItemKind {
+    let attrs = cx.tcx.hir().attrs(item.hir_id());
+    if kind == MacroKind::Derive &&
+        let Some(derive_name) = attrs
+            .lists(sym::proc_macro_derive)
+            .find_map(|mi| mi.ident())
+    {
+        *name = derive_name.name;
+    }
+
+    let mut helpers = Vec::new();
+    for mi in attrs.lists(sym::proc_macro_derive) {
+        if !mi.has_name(sym::attributes) {
+            continue;
+        }
+
+        if let Some(list) = mi.meta_item_list() {
+            for inner_mi in list {
+                if let Some(ident) = inner_mi.ident() {
+                    helpers.push(ident.name);
+                }
+            }
+        }
+    }
+    ProcMacroItem(ProcMacro { kind, helpers })
+}
+
 fn clean_fn_or_proc_macro<'tcx>(
     item: &hir::Item<'tcx>,
     sig: &hir::FnSig<'tcx>,
@@ -930,31 +962,7 @@ fn clean_fn_or_proc_macro<'tcx>(
         }
     });
     match macro_kind {
-        Some(kind) => {
-            if kind == MacroKind::Derive {
-                *name = attrs
-                    .lists(sym::proc_macro_derive)
-                    .find_map(|mi| mi.ident())
-                    .expect("proc-macro derives require a name")
-                    .name;
-            }
-
-            let mut helpers = Vec::new();
-            for mi in attrs.lists(sym::proc_macro_derive) {
-                if !mi.has_name(sym::attributes) {
-                    continue;
-                }
-
-                if let Some(list) = mi.meta_item_list() {
-                    for inner_mi in list {
-                        if let Some(ident) = inner_mi.ident() {
-                            helpers.push(ident.name);
-                        }
-                    }
-                }
-            }
-            ProcMacroItem(ProcMacro { kind, helpers })
-        }
+        Some(kind) => clean_proc_macro(item, name, kind, cx),
         None => {
             let mut func = clean_function(cx, sig, generics, FunctionArgs::Body(body_id));
             clean_fn_decl_legacy_const_generics(&mut func, attrs);
@@ -2247,16 +2255,17 @@ fn clean_maybe_renamed_item<'tcx>(
                 fields: variant_data.fields().iter().map(|x| clean_field(x, cx)).collect(),
             }),
             ItemKind::Impl(impl_) => return clean_impl(impl_, item.owner_id.def_id, cx),
-            // proc macros can have a name set by attributes
-            ItemKind::Fn(ref sig, generics, body_id) => {
-                clean_fn_or_proc_macro(item, sig, generics, body_id, &mut name, cx)
-            }
-            ItemKind::Macro(ref macro_def, _) => {
+            ItemKind::Macro(ref macro_def, MacroKind::Bang) => {
                 let ty_vis = cx.tcx.visibility(def_id);
                 MacroItem(Macro {
                     source: display_macro_source(cx, name, macro_def, def_id, ty_vis),
                 })
             }
+            ItemKind::Macro(_, macro_kind) => clean_proc_macro(item, &mut name, macro_kind, cx),
+            // proc macros can have a name set by attributes
+            ItemKind::Fn(ref sig, generics, body_id) => {
+                clean_fn_or_proc_macro(item, sig, generics, body_id, &mut name, cx)
+            }
             ItemKind::Trait(_, _, generics, bounds, item_ids) => {
                 let items = item_ids
                     .iter()

tests/rustdoc/compiler-derive-proc-macro.rs

@@ -0,0 +1,15 @@
+// This test ensures that compiler builtin proc-macros are considered as such.
+
+#![crate_name = "foo"]
+
+// @has 'foo/index.html'
+// Each compiler builtin proc-macro has a trait equivalent so we should have
+// a trait section as well.
+// @count - '//*[@id="main-content"]//*[@class="small-section-header"]' 2
+// @has - '//*[@id="main-content"]//*[@class="small-section-header"]' 'Traits'
+// @has - '//*[@id="main-content"]//*[@class="small-section-header"]' 'Derive Macros'
+
+// Now checking the correct file is generated as well.
+// @has 'foo/derive.Clone.html'
+// @!has 'foo/macro.Clone.html'
+pub use std::clone::Clone;

tests/rustdoc/macro_pub_in_module.rs

@@ -7,8 +7,8 @@
 #![crate_name = "krate"]
 #![no_core]
 
- // @has external_crate/some_module/macro.external_macro.html
-  // @!has external_crate/macro.external_macro.html
+// @has external_crate/some_module/macro.external_macro.html
+// @!has external_crate/macro.external_macro.html
 extern crate external_crate;
 
 pub mod inner {
@@ -16,13 +16,17 @@ pub mod inner {
     // @!has krate/macro.raw_const.html
     pub macro raw_const() {}
 
-    // @has krate/inner/macro.test.html
+    // @has krate/inner/attr.test.html
     // @!has krate/macro.test.html
+    // @!has krate/inner/macro.test.html
+    // @!has krate/attr.test.html
     #[rustc_builtin_macro]
     pub macro test($item:item) {}
 
-    // @has krate/inner/macro.Clone.html
+    // @has krate/inner/derive.Clone.html
+    // @!has krate/inner/macro.Clone.html
     // @!has krate/macro.Clone.html
+    // @!has krate/derive.Clone.html
     #[rustc_builtin_macro]
     pub macro Clone($item:item) {}