From d50a4753b8cffdb17e2d83282d95b61e266521fb Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Tue, 2 Nov 2021 14:36:54 +0100
Subject: [PATCH] Split doc_cfg and doc_auto_cfg features

---
 compiler/rustc_feature/src/active.rs          | 3 +++
 compiler/rustc_span/src/symbol.rs             | 1 +
 src/librustdoc/clean/types.rs                 | 9 ++++++---
 src/test/rustdoc/doc-auto-cfg.rs              | 8 ++++++++
 src/test/rustdoc/doc-cfg-hide.rs              | 2 +-
 src/test/rustdoc/doc-cfg-implicit.rs          | 2 +-
 src/test/rustdoc/feature-gate-doc_auto_cfg.rs | 8 ++++++++
 7 files changed, 28 insertions(+), 5 deletions(-)
 create mode 100644 src/test/rustdoc/doc-auto-cfg.rs
 create mode 100644 src/test/rustdoc/feature-gate-doc_auto_cfg.rs

diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 2bbfb561ba5..42af8e1faad 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -688,6 +688,9 @@ pub fn set(&self, features: &mut Features, span: Span) {
     /// not changed from prior instances of the same struct (RFC #2528)
     (incomplete, type_changing_struct_update, "1.58.0", Some(86555), None),
 
+    /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
+    (active, doc_auto_cfg, "1.58.0", Some(43781), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 1b431589632..5f71e955e2a 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -549,6 +549,7 @@
         div_assign,
         doc,
         doc_alias,
+        doc_auto_cfg,
         doc_cfg,
         doc_cfg_hide,
         doc_keyword,
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 88fffaecb93..56ae43855de 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -789,6 +789,7 @@ fn other_attrs(&self) -> Vec<ast::Attribute> {
     fn cfg(&self, tcx: TyCtxt<'_>, hidden_cfg: &FxHashSet<Cfg>) -> Option<Arc<Cfg>> {
         let sess = tcx.sess;
         let doc_cfg_active = tcx.features().doc_cfg;
+        let doc_auto_cfg_active = tcx.features().doc_auto_cfg;
 
         fn single<T: IntoIterator>(it: T) -> Option<T::Item> {
             let mut iter = it.into_iter();
@@ -799,24 +800,26 @@ fn single<T: IntoIterator>(it: T) -> Option<T::Item> {
             Some(item)
         }
 
-        let mut cfg = if doc_cfg_active {
+        let mut cfg = if doc_cfg_active || doc_auto_cfg_active {
             let mut doc_cfg = self
                 .iter()
                 .filter(|attr| attr.has_name(sym::doc))
                 .flat_map(|attr| attr.meta_item_list().unwrap_or_else(Vec::new))
                 .filter(|attr| attr.has_name(sym::cfg))
                 .peekable();
-            if doc_cfg.peek().is_some() {
+            if doc_cfg.peek().is_some() && doc_cfg_active {
                 doc_cfg
                     .filter_map(|attr| Cfg::parse(attr.meta_item()?).ok())
                     .fold(Cfg::True, |cfg, new_cfg| cfg & new_cfg)
-            } else {
+            } else if doc_auto_cfg_active {
                 self.iter()
                     .filter(|attr| attr.has_name(sym::cfg))
                     .filter_map(|attr| single(attr.meta_item_list()?))
                     .filter_map(|attr| Cfg::parse(attr.meta_item()?).ok())
                     .filter(|cfg| !hidden_cfg.contains(cfg))
                     .fold(Cfg::True, |cfg, new_cfg| cfg & new_cfg)
+            } else {
+                Cfg::True
             }
         } else {
             Cfg::True
diff --git a/src/test/rustdoc/doc-auto-cfg.rs b/src/test/rustdoc/doc-auto-cfg.rs
new file mode 100644
index 00000000000..fcdd8354569
--- /dev/null
+++ b/src/test/rustdoc/doc-auto-cfg.rs
@@ -0,0 +1,8 @@
+#![feature(doc_auto_cfg)]
+
+#![crate_name = "foo"]
+
+// @has foo/fn.foo.html
+// @has - '//*[@class="item-info"]/*[@class="stab portability"]' 'non-test'
+#[cfg(not(test))]
+pub fn foo() {}
diff --git a/src/test/rustdoc/doc-cfg-hide.rs b/src/test/rustdoc/doc-cfg-hide.rs
index b9d0d323137..424fa6d6a91 100644
--- a/src/test/rustdoc/doc-cfg-hide.rs
+++ b/src/test/rustdoc/doc-cfg-hide.rs
@@ -1,5 +1,5 @@
 #![crate_name = "oud"]
-#![feature(doc_cfg, doc_cfg_hide)]
+#![feature(doc_auto_cfg, doc_cfg, doc_cfg_hide)]
 
 #![doc(cfg_hide(feature = "solecism"))]
 
diff --git a/src/test/rustdoc/doc-cfg-implicit.rs b/src/test/rustdoc/doc-cfg-implicit.rs
index 36c2025785d..5d17a4ede6a 100644
--- a/src/test/rustdoc/doc-cfg-implicit.rs
+++ b/src/test/rustdoc/doc-cfg-implicit.rs
@@ -1,5 +1,5 @@
 #![crate_name = "funambulism"]
-#![feature(doc_cfg)]
+#![feature(doc_auto_cfg, doc_cfg)]
 
 // @has 'funambulism/struct.Disorbed.html'
 // @count   - '//*[@class="stab portability"]' 1
diff --git a/src/test/rustdoc/feature-gate-doc_auto_cfg.rs b/src/test/rustdoc/feature-gate-doc_auto_cfg.rs
new file mode 100644
index 00000000000..da76381e480
--- /dev/null
+++ b/src/test/rustdoc/feature-gate-doc_auto_cfg.rs
@@ -0,0 +1,8 @@
+#![feature(doc_cfg)]
+
+#![crate_name = "foo"]
+
+// @has foo/fn.foo.html
+// @count - '//*[@class="item-info"]/*[@class="stab portability"]' 0
+#[cfg(not(test))]
+pub fn foo() {}