Improve feature collection and permit macro attribute input

gcc/rust/Make-lang.in

@@ -94,6 +94,7 @@ GRS_OBJS = \
     rust/rust-compile-resolve-path.o \
     rust/rust-macro-expand.o \
     rust/rust-cfg-strip.o \
+    rust/rust-early-cfg-strip.o \
     rust/rust-expand-visitor.o \
     rust/rust-ast-builder.o \
     rust/rust-derive.o \
@@ -229,6 +230,8 @@ GRS_OBJS = \
     rust/rust-builtins.o \
     rust/rust-feature.o \
     rust/rust-feature-gate.o \
+    rust/rust-feature-store.o \
+    rust/rust-feature-collector.o \
     rust/rust-ast-validation.o \
     rust/rust-dir-owner.o \
     rust/rust-unicode.o \

gcc/rust/ast/rust-ast-full-decls.h

@@ -34,7 +34,7 @@ class DelimTokenTree;
 class PathSegment;
 class SimplePathSegment;
 class SimplePath;
-struct Attribute;
+class Attribute;
 class MetaItemInner;
 class AttrInputMetaItemContainer;
 class MetaItem;

gcc/rust/ast/rust-ast-visitor.cc

@@ -194,6 +194,14 @@ DefaultASTVisitor::visit (AST::LiteralExpr &expr)
   visit_outer_attrs (expr);
 }
 
+void
+DefaultASTVisitor::visit (AST::Attribute &attribute)
+{
+  visit (attribute.get_path ());
+  if (attribute.has_attr_input ())
+    visit (attribute.get_attr_input ());
+}
+
 void
 DefaultASTVisitor::visit (AST::AttrInputLiteral &attr_input)
 {

gcc/rust/ast/rust-ast-visitor.h

@@ -39,6 +39,7 @@ class ASTVisitor
 
   // rust-ast.h
   // virtual void visit(AttrInput& attr_input) = 0;
+  virtual void visit (AST::Attribute &attribute) = 0;
   // virtual void visit(TokenTree& token_tree) = 0;
   // virtual void visit(MacroMatch& macro_match) = 0;
   virtual void visit (Token &tok) = 0;
@@ -444,7 +445,7 @@ class DefaultASTVisitor : public ASTVisitor
   virtual void visit (AST::StructPatternElements &spe);
   virtual void visit (AST::MaybeNamedParam &param);
 
-  void visit (AST::Attribute &attribute) {}
+  virtual void visit (AST::Attribute &attribute) override;
 
   template <typename T> void visit_outer_attrs (T &node)
   {

gcc/rust/ast/rust-ast.cc

@@ -253,6 +253,12 @@ Attribute::as_string () const
     return path_str + attr_input->as_string ();
 }
 
+void
+Attribute::accept_vis (ASTVisitor &vis)
+{
+  vis.visit (*this);
+}
+
 bool
 Attribute::is_derive () const
 {

gcc/rust/ast/rust-ast.h

@@ -565,9 +565,8 @@ struct Visibility
 
 // aka Attr
 // Attribute AST representation
-struct Attribute
+class Attribute : Visitable
 {
-private:
   SimplePath path;
 
   // bool has_attr_input;
@@ -577,6 +576,8 @@ struct Attribute
 
   bool inner_attribute;
 
+  NodeId node_id;
+
   // TODO: maybe a variable storing whether attr input is parsed or not
 
 public:
@@ -587,7 +588,8 @@ struct Attribute
   Attribute (SimplePath path, std::unique_ptr<AttrInput> input,
 	     location_t locus = UNDEF_LOCATION, bool inner_attribute = false)
     : path (std::move (path)), attr_input (std::move (input)), locus (locus),
-      inner_attribute (inner_attribute)
+      inner_attribute (inner_attribute),
+      node_id (Analysis::Mappings::get ().get_next_node_id ())
   {}
 
   bool is_derive () const;
@@ -685,11 +687,13 @@ struct Attribute
 
   bool is_inner_attribute () const { return inner_attribute; }
 
-  // no visitor pattern as not currently polymorphic
+  void accept_vis (ASTVisitor &vis) override;
 
   const SimplePath &get_path () const { return path; }
   SimplePath &get_path () { return path; }
 
+  NodeId get_node_id () { return node_id; }
+
   // Call to parse attribute body to meta item syntax.
   void parse_attr_to_meta_item ();
 

gcc/rust/checks/errors/feature/contrib/fetch

@@ -18,7 +18,7 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-RUST_VERSION="1.49.0"
+RUST_VERSION="1.50.0"
 
 [ $# = 1 ] || exit 1
 
@@ -27,4 +27,4 @@ RUST_VERSION="1.49.0"
 URL_PREFIX='https://raw.githubusercontent.com/rust-lang/rust/refs/tags'
 URL_TEMPLATE="$URL_PREFIX/$RUST_VERSION/compiler/rustc_feature/src"
 
-wget -O $1 "$URL_TEMPLATE"/{accepted,active,removed}.rs
+wget -O $1 "$URL_TEMPLATE/accepted.rs" "$URL_TEMPLATE/active.rs" "$URL_TEMPLATE/removed.rs"

gcc/rust/checks/errors/feature/rust-feature-collector.cc

@@ -0,0 +1,117 @@
+// Copyright (C) 2026 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-feature-collector.h"
+#include "rust-attribute-values.h"
+
+namespace Rust {
+namespace Features {
+
+FeatureCollector::FeatureCollector () : features (CrateFeatures{UNKNOWN_NODEID})
+{}
+
+CrateFeatures
+FeatureCollector::collect (AST::Crate &crate)
+{
+  features.valid_lang_features.clear ();
+  features.valid_lib_features.clear ();
+  features.crate_id = crate.get_node_id ();
+
+  visit (crate);
+
+  return features;
+}
+
+namespace {
+bool
+is_feature_attribute (const AST::Attribute &attribute)
+{
+  return Values::Attributes::FEATURE == attribute.get_path ().as_string ();
+}
+
+// check for empty feature, such as `#![feature], this is an error
+bool
+is_valid_feature_attribute (const AST::Attribute &attribute)
+{
+  return !attribute.empty_input ();
+}
+} // namespace
+
+void
+FeatureCollector::add_features_from_token_tree (
+  const AST::DelimTokenTree &delim_ttree)
+{
+  std::unique_ptr<AST::AttrInputMetaItemContainer> meta_item (
+    delim_ttree.parse_to_meta_item ());
+  add_features_from_meta_item_container (*meta_item);
+}
+
+void
+FeatureCollector::add_features_from_meta_item_container (
+  const AST::AttrInputMetaItemContainer &meta_item_container)
+{
+  for (const auto &item : meta_item_container.get_items ())
+    {
+      const auto &name_str = item->as_string ();
+
+      // TODO: detect duplicates
+      if (auto tname = Feature::as_name (name_str))
+	features.valid_lang_features.insert (*tname);
+      else
+	features.valid_lib_features.emplace (name_str, item->get_locus ());
+    }
+}
+
+void
+FeatureCollector::identify_feature (const AST::Attribute &attribute)
+{
+  if (is_feature_attribute (attribute))
+    {
+      if (!is_valid_feature_attribute (attribute))
+	{
+	  rust_error_at (attribute.get_locus (), ErrorCode::E0556,
+			 "malformed %<feature%> attribute input");
+	  return;
+	}
+      const auto &attr_input = attribute.get_attr_input ();
+      auto type = attr_input.get_attr_input_type ();
+      if (type == AST::AttrInput::AttrInputType::TOKEN_TREE)
+	{
+	  const auto &delim_ttree = static_cast<const AST::DelimTokenTree &> (
+	    attribute.get_attr_input ());
+	  add_features_from_token_tree (delim_ttree);
+	}
+      else if (type == AST::AttrInput::AttrInputType::META_ITEM)
+	{
+	  // We can find a meta item in #[cfg(toto),feature(xxxx)]
+	  const auto &meta_item_container
+	    = static_cast<const AST::AttrInputMetaItemContainer &> (attr_input);
+	  add_features_from_meta_item_container (meta_item_container);
+	}
+    }
+}
+
+void
+FeatureCollector::visit (AST::Crate &crate)
+{
+  for (const auto &attribute : crate.inner_attrs)
+    identify_feature (attribute);
+}
+
+} // namespace Features
+} // namespace Rust

gcc/rust/checks/errors/feature/rust-feature-collector.h

@@ -0,0 +1,62 @@
+// Copyright (C) 2026 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+#ifndef RUST_FEATURE_COLLECTOR_H
+#define RUST_FEATURE_COLLECTOR_H
+
+#include "rust-feature.h"
+#include "rust-ast-visitor.h"
+
+namespace Rust {
+namespace Features {
+
+/** Helper structure gathering all features enabled within a given crate
+ * using the #![feature(XXXXX)] syntax.
+ **/
+struct CrateFeatures
+{
+  // The node id identifying the crate those features belong to.
+  NodeId crate_id;
+  // Language features that have been declared within the crate.
+  std::set<Feature::Name> valid_lang_features;
+  // Library features that have been declared within the crate.
+  std::map<std::string, location_t> valid_lib_features;
+
+  CrateFeatures (NodeId crate_id) : crate_id (crate_id) {}
+};
+
+class FeatureCollector : public AST::DefaultASTVisitor
+{
+public:
+  FeatureCollector ();
+
+  CrateFeatures collect (AST::Crate &crate);
+
+private:
+  CrateFeatures features;
+
+  using AST::DefaultASTVisitor::visit;
+  void visit (AST::Crate &crate) override;
+  void identify_feature (const AST::Attribute &attribute);
+  void add_features_from_token_tree (const AST::DelimTokenTree &delim_ttree);
+  void add_features_from_meta_item_container (
+    const AST::AttrInputMetaItemContainer &meta_item_container);
+};
+} // namespace Features
+} // namespace Rust
+
+#endif /* ! RUST_FEATURE_COLLECTOR_H */

gcc/rust/checks/errors/feature/rust-feature-defs.h

@@ -223,8 +223,6 @@ FEATURE_ACTIVE ("fundamental", FUNDAMENTAL, "1.0.0", ISSUE_SOME (29635),
 FEATURE_ACTIVE ("unboxed_closures", UNBOXED_CLOSURES, "1.0.0",
 		ISSUE_SOME (29625), EDITION_NONE)
 FEATURE_ACTIVE ("linkage", LINKAGE, "1.0.0", ISSUE_SOME (29603), EDITION_NONE)
-FEATURE_ACTIVE ("optin_builtin_traits", OPTIN_BUILTIN_TRAITS, "1.0.0",
-		ISSUE_SOME (13231), EDITION_NONE)
 FEATURE_ACTIVE ("box_patterns", BOX_PATTERNS, "1.0.0", ISSUE_SOME (29641),
 		EDITION_NONE)
 FEATURE_ACTIVE ("prelude_import", PRELUDE_IMPORT, "1.2.0", ISSUE_NONE,
@@ -257,6 +255,8 @@ FEATURE_ACTIVE ("test_2018_feature", TEST_2018_FEATURE, "1.31.0", ISSUE_NONE,
 FEATURE_ACTIVE ("no_niche", NO_NICHE, "1.42.0", ISSUE_NONE, EDITION_NONE)
 FEATURE_ACTIVE ("rustc_allow_const_fn_unstable", RUSTC_ALLOW_CONST_FN_UNSTABLE,
 		"1.49.0", ISSUE_SOME (69399), EDITION_NONE)
+FEATURE_ACTIVE ("auto_traits", AUTO_TRAITS, "1.50.0", ISSUE_SOME (13231),
+		EDITION_NONE)
 FEATURE_ACTIVE ("arm_target_feature", ARM_TARGET_FEATURE, "1.27.0",
 		ISSUE_SOME (44839), EDITION_NONE)
 FEATURE_ACTIVE ("aarch64_target_feature", AARCH64_TARGET_FEATURE, "1.27.0",
@@ -519,6 +519,10 @@ FEATURE_ACTIVE ("destructuring_assignment", DESTRUCTURING_ASSIGNMENT, "1.49.0",
 		ISSUE_SOME (71126), EDITION_NONE)
 FEATURE_ACTIVE ("cfg_panic", CFG_PANIC, "1.49.0", ISSUE_SOME (77443),
 		EDITION_NONE)
+FEATURE_ACTIVE ("capture_disjoint_fields", CAPTURE_DISJOINT_FIELDS, "1.49.0",
+		ISSUE_SOME (53488), EDITION_NONE)
+FEATURE_ACTIVE ("extended_key_value_attributes", EXTENDED_KEY_VALUE_ATTRIBUTES,
+		"1.50.0", ISSUE_SOME (78835), EDITION_NONE)
 FEATURE_REMOVED ("import_shadowing", IMPORT_SHADOWING, "1.0.0", ISSUE_NONE,
 		 REASON_NONE)
 FEATURE_REMOVED ("managed_boxes", MANAGED_BOXES, "1.0.0", ISSUE_NONE,
@@ -550,6 +554,8 @@ FEATURE_REMOVED (
   "custom_attribute", CUSTOM_ATTRIBUTE, "1.0.0", ISSUE_SOME (29642),
   REASON_SOME (
     "removed in favor of `#![register_tool]` and `#![register_attr]`"))
+FEATURE_REMOVED ("optin_builtin_traits", OPTIN_BUILTIN_TRAITS, "1.0.0",
+		 ISSUE_SOME (13231), REASON_SOME ("renamed to `auto_traits`"))
 FEATURE_REMOVED ("pushpop_unsafe", PUSHPOP_UNSAFE, "1.2.0", ISSUE_NONE,
 		 REASON_NONE)
 FEATURE_REMOVED ("needs_allocator", NEEDS_ALLOCATOR, "1.4.0",