Strenghten checks for doc(auto_cfg(show/hide)) attributes

Author: GuillaumeGomez

compiler/rustc_passes/messages.ftl

@@ -178,6 +178,9 @@ passes_doc_auto_cfg_expects_hide_or_show =
 passes_doc_auto_cfg_hide_show_expects_list =
     `#![doc(auto_cfg({$attr_name}(...)))]` only expects a list of items
 
+passes_doc_auto_cfg_hide_show_unexpected_item =
+    `#![doc(auto_cfg({$attr_name}(...)))]` only accepts identifiers or key/values items
+
 passes_doc_auto_cfg_wrong_literal =
     `expected boolean for #[doc(auto_cfg = ...)]`
 

compiler/rustc_passes/src/check_attr.rs

@@ -1390,7 +1390,20 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             meta.span,
                             errors::DocAutoCfgExpectsHideOrShow,
                         );
-                    } else if item.meta_item_list().is_none() {
+                    } else if let Some(list) = item.meta_item_list() {
+                        for item in list {
+                            if item.meta_item_list().is_some() {
+                                self.tcx.emit_node_span_lint(
+                                    INVALID_DOC_ATTRIBUTES,
+                                    hir_id,
+                                    item.span(),
+                                    errors::DocAutoCfgHideShowUnexpectedItem {
+                                        attr_name: attr_name.as_str(),
+                                    },
+                                );
+                            }
+                        }
+                    } else {
                         self.tcx.emit_node_span_lint(
                             INVALID_DOC_ATTRIBUTES,
                             hir_id,

compiler/rustc_passes/src/errors.rs

@@ -375,6 +375,12 @@ pub(crate) struct DocAutoCfgHideShowExpectsList<'a> {
     pub attr_name: &'a str,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(passes_doc_auto_cfg_hide_show_unexpected_item)]
+pub(crate) struct DocAutoCfgHideShowUnexpectedItem<'a> {
+    pub attr_name: &'a str,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(passes_doc_test_unknown_any)]
 pub(crate) struct DocTestUnknownAny {

library/alloc/src/lib.rs

@@ -78,7 +78,6 @@
 #![cfg_attr(
     not(bootstrap),
     doc(auto_cfg(hide(
-        test,
         no_global_oom_handling,
         no_rc,
         no_sync,

library/std/src/lib.rs

@@ -243,13 +243,7 @@
         not(no_global_oom_handling)
     ))
 )]
-#![cfg_attr(
-    not(bootstrap),
-    doc(auto_cfg(hide(
-        test,
-        no_global_oom_handling,
-    )))
-)]
+#![cfg_attr(not(bootstrap), doc(auto_cfg(hide(no_global_oom_handling))))]
 // Don't link to std. We are std.
 #![no_std]
 // Tell the compiler to link to either panic_abort or panic_unwind

tests/rustdoc-ui/lints/doc_cfg_hide.rs

@@ -1,2 +1,3 @@
 #![doc(auto_cfg(hide = "test"))] //~ ERROR
 #![doc(auto_cfg(hide))] //~ ERROR
+#![doc(auto_cfg(hide(not(windows))))] //~ ERROR

tests/rustdoc-ui/lints/doc_cfg_hide.stderr

@@ -12,5 +12,11 @@ error: `#![doc(auto_cfg(hide(...)))]` only expects a list of items
 LL | #![doc(auto_cfg(hide))]
    |        ^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: `#![doc(auto_cfg(hide(...)))]` only accepts identifiers or key/values items
+  --> $DIR/doc_cfg_hide.rs:3:22
+   |
+LL | #![doc(auto_cfg(hide(not(windows))))]
+   |                      ^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors