{"id":2223288,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2223288/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20260414231905.191063-22-arthur.cohen@embecosm.com/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.1/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260414231905.191063-22-arthur.cohen@embecosm.com>","date":"2026-04-14T23:18:43","name":"[COMMITTED,22/43] gccrs: Move builtin attribute checking to its own pass","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"b00d88da20ddfc835590484615275cbc48fdcf3c","submitter":{"id":83476,"url":"http://patchwork.ozlabs.org/api/1.1/people/83476/?format=json","name":"Arthur Cohen","email":"arthur.cohen@embecosm.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20260414231905.191063-22-arthur.cohen@embecosm.com/mbox/","series":[{"id":499900,"url":"http://patchwork.ozlabs.org/api/1.1/series/499900/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=499900","date":"2026-04-14T23:18:24","name":"[COMMITTED,01/43] gccrs: testsuite:Add a testcase for setup_associated_types","version":1,"mbox":"http://patchwork.ozlabs.org/series/499900/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2223288/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2223288/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=embecosm.com header.i=@embecosm.com header.a=rsa-sha256\n header.s=google header.b=MNcwOvrC;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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The error message\n\twill now be emitted from the builtin attribute checking pass.\n\t* rust-session-manager.cc (Session::compile_crate): Add builtin\n\tattribute checking step after expansion.\n\t* util/rust-attributes.cc (Attributes::is_known): Move down.\n\t(Attributes::extract_string_literal): Likewise.\n\t(Attributes::valid_outer_attribute): Add a function to retrieve outer/\n\tinner status for a given builtin attribute value.\n\t(AttributeChecker::visit): Move some checking to builtin attribute\n\tchecker.\n\t(identify_builtin): Rename function from here ...\n\t(lookup_builtin): ... to here.\n\t(check_doc_alias): Move to builtin attribute checker.\n\t(check_doc_attribute): Likewise.\n\t(check_deprecated_attribute): Likewise.\n\t(check_valid_attribute_for_item): Likewise.\n\t(AttributeChecker::check_inner_attribute): Likewise.\n\t(check_link_section_attribute): Likewise.\n\t(check_export_name_attribute): Likewise.\n\t(check_lint_attribute): Likewise.\n\t(check_no_mangle_function): Likewise.\n\t(is_proc_macro_type): Update function call name.\n\t* util/rust-attributes.h (identify_builtin): Update prototype.\n\t(lookup_builtin): Likewise.\n\t* checks/errors/rust-builtin-attribute-checker.cc: New file.\n\t* checks/errors/rust-builtin-attribute-checker.h: New file.\n\ngcc/testsuite/ChangeLog:\n\n\t* rust/compile/issue-4226.rs: Update text to match error message from\n\tattribute checking pass that was not triggered before.\n\nSigned-off-by: Pierre-Emmanuel Patry \n---\n gcc/rust/Make-lang.in | 1 +\n .../errors/rust-builtin-attribute-checker.cc | 602 ++++++++++++++++++\n .../errors/rust-builtin-attribute-checker.h | 58 ++\n gcc/rust/hir/rust-ast-lower-base.cc | 8 +-\n gcc/rust/rust-session-manager.cc | 3 +\n gcc/rust/util/rust-attributes.cc | 571 ++---------------\n gcc/rust/util/rust-attributes.h | 4 +-\n gcc/testsuite/rust/compile/issue-4226.rs | 4 +-\n 8 files changed, 725 insertions(+), 526 deletions(-)\n create mode 100644 gcc/rust/checks/errors/rust-builtin-attribute-checker.cc\n create mode 100644 gcc/rust/checks/errors/rust-builtin-attribute-checker.h","diff":"diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in\nindex 4c394d39c0b..fc11abf1f1c 100644\n--- a/gcc/rust/Make-lang.in\n+++ b/gcc/rust/Make-lang.in\n@@ -126,6 +126,7 @@ GRS_OBJS = \\\n rust/rust-hir.o \\\n rust/rust-hir-map.o \\\n rust/rust-attributes.o \\\n+ rust/rust-builtin-attribute-checker.o \\\n rust/rust-keyword-values.o \\\n rust/rust-abi.o \\\n rust/rust-token-converter.o \\\ndiff --git a/gcc/rust/checks/errors/rust-builtin-attribute-checker.cc b/gcc/rust/checks/errors/rust-builtin-attribute-checker.cc\nnew file mode 100644\nindex 00000000000..8cb251f7686\n--- /dev/null\n+++ b/gcc/rust/checks/errors/rust-builtin-attribute-checker.cc\n@@ -0,0 +1,602 @@\n+// Copyright (C) 2026 Free Software Foundation, Inc.\n+\n+// This file is part of GCC.\n+\n+// GCC is free software; you can redistribute it and/or modify it under\n+// the terms of the GNU General Public License as published by the Free\n+// Software Foundation; either version 3, or (at your option) any later\n+// version.\n+\n+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY\n+// WARRANTY; without even the implied warranty of MERCHANTABILITY or\n+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License\n+// for more details.\n+\n+// You should have received a copy of the GNU General Public License\n+// along with GCC; see the file COPYING3. If not see\n+// .\n+\n+#include \"rust-builtin-attribute-checker.h\"\n+#include \"optional.h\"\n+#include \"rust-attributes.h\"\n+#include \"rust-attribute-values.h\"\n+#include \"rust-session-manager.h\"\n+\n+namespace Rust {\n+namespace Analysis {\n+\n+using Attrs = Values::Attributes;\n+\n+void\n+check_inner_attribute (const AST::Attribute &attribute)\n+{\n+ auto result_opt = lookup_builtin (attribute);\n+ if (!result_opt.has_value ())\n+ return;\n+ auto result = result_opt.value ();\n+\n+ if (Attributes::valid_outer_attribute (result.name))\n+ rust_error_at (attribute.get_locus (),\n+\t\t \"attribute cannot be used at crate level\");\n+}\n+\n+/**\n+ * Check that the string given to #[doc(alias = ...)] or #[doc(alias(...))] is\n+ * valid.\n+ *\n+ * This means no whitespace characters other than spaces and no quoting\n+ * characters.\n+ */\n+static void\n+check_doc_alias (const std::string &alias_input, const location_t locus)\n+{\n+ // FIXME: The locus here is for the whole attribute. Can we get the locus\n+ // of the alias input instead?\n+ for (auto c : alias_input)\n+ if ((ISSPACE (c) && c != ' ') || c == '\\'' || c == '\\\"')\n+ {\n+\tauto to_print = std::string (1, c);\n+\tswitch (c)\n+\t {\n+\t case '\\n':\n+\t to_print = \"\\\\n\";\n+\t break;\n+\t case '\\t':\n+\t to_print = \"\\\\t\";\n+\t break;\n+\t default:\n+\t break;\n+\t }\n+\trust_error_at (locus,\n+\t\t \"invalid character used in %<#[doc(alias)]%> input: %qs\",\n+\t\t to_print.c_str ());\n+ }\n+\n+ if (alias_input.empty ())\n+ return;\n+\n+ if (alias_input.front () == ' ' || alias_input.back () == ' ')\n+ rust_error_at (locus,\n+\t\t \"%<#[doc(alias)]%> input cannot start or end with a space\");\n+}\n+\n+static void\n+check_doc_attribute (const AST::Attribute &attribute)\n+{\n+ if (!attribute.has_attr_input ())\n+ {\n+ rust_error_at (\n+\tattribute.get_locus (),\n+\t\"valid forms for the attribute are \"\n+\t\"%<#[doc(hidden|inline|...)]%> and %<#[doc = \\\" string \\\"]%>\");\n+ return;\n+ }\n+\n+ switch (attribute.get_attr_input ().get_attr_input_type ())\n+ {\n+ case AST::AttrInput::LITERAL:\n+ case AST::AttrInput::META_ITEM:\n+ case AST::AttrInput::EXPR:\n+ break;\n+ // FIXME: Handle them as well\n+\n+ case AST::AttrInput::TOKEN_TREE:\n+ {\n+\t// FIXME: This doesn't check for #[doc(alias(...))]\n+\tconst auto &option = static_cast (\n+\t attribute.get_attr_input ());\n+\tauto *meta_item = option.parse_to_meta_item ();\n+\n+\tfor (auto &item : meta_item->get_items ())\n+\t {\n+\t if (item->is_key_value_pair ())\n+\t {\n+\t\tauto name_value\n+\t\t = static_cast (item.get ())\n+\t\t ->get_name_value_pair ();\n+\n+\t\t// FIXME: Check for other stuff than #[doc(alias = ...)]\n+\t\tif (name_value.first.as_string () == \"alias\")\n+\t\t check_doc_alias (name_value.second, attribute.get_locus ());\n+\t }\n+\t }\n+\tbreak;\n+ }\n+ }\n+}\n+\n+static void\n+check_deprecated_attribute (const AST::Attribute &attribute)\n+{\n+ if (!attribute.has_attr_input ())\n+ return;\n+\n+ const auto &input = attribute.get_attr_input ();\n+\n+ if (input.get_attr_input_type () != AST::AttrInput::META_ITEM)\n+ return;\n+\n+ auto &meta = static_cast (input);\n+\n+ for (auto ¤t : meta.get_items ())\n+ {\n+ switch (current->get_kind ())\n+\t{\n+\tcase AST::MetaItemInner::Kind::MetaItem:\n+\t {\n+\t auto *meta_item = static_cast (current.get ());\n+\n+\t switch (meta_item->get_item_kind ())\n+\t {\n+\t case AST::MetaItem::ItemKind::NameValueStr:\n+\t\t{\n+\t\t auto *nv = static_cast (meta_item);\n+\n+\t\t const std::string key = nv->get_name ().as_string ();\n+\n+\t\t if (key != \"since\" && key != \"note\")\n+\t\t {\n+\t\t rust_error_at (nv->get_locus (), \"unknown meta item %qs\",\n+\t\t\t\t key.c_str ());\n+\t\t rust_inform (nv->get_locus (),\n+\t\t\t\t \"expected one of %, %\");\n+\t\t }\n+\t\t}\n+\t\tbreak;\n+\n+\t case AST::MetaItem::ItemKind::Path:\n+\t\t{\n+\t\t // #[deprecated(a,a)]\n+\t\t auto *p = static_cast (meta_item);\n+\n+\t\t std::string ident = p->get_path ().as_string ();\n+\n+\t\t rust_error_at (p->get_locus (), \"unknown meta item %qs\",\n+\t\t\t\t ident.c_str ());\n+\t\t rust_inform (p->get_locus (),\n+\t\t\t \"expected one of %, %\");\n+\t\t}\n+\t\tbreak;\n+\n+\t case AST::MetaItem::ItemKind::Word:\n+\t\t{\n+\t\t // #[deprecated(\"a\")]\n+\t\t auto *w = static_cast (meta_item);\n+\n+\t\t rust_error_at (\n+\t\t w->get_locus (),\n+\t\t \"item in % must be a key/value pair\");\n+\t\t}\n+\t\tbreak;\n+\n+\t case AST::MetaItem::ItemKind::PathExpr:\n+\t\t{\n+\t\t // #[deprecated(since=a)]\n+\t\t auto *px = static_cast (meta_item);\n+\n+\t\t rust_error_at (\n+\t\t px->get_locus (),\n+\t\t \"expected unsuffixed literal or identifier, found %qs\",\n+\t\t px->get_expr ().as_string ().c_str ());\n+\t\t}\n+\t\tbreak;\n+\n+\t case AST::MetaItem::ItemKind::Seq:\n+\t case AST::MetaItem::ItemKind::ListPaths:\n+\t case AST::MetaItem::ItemKind::ListNameValueStr:\n+\t default:\n+\t\tgcc_unreachable ();\n+\t\tbreak;\n+\t }\n+\t }\n+\t break;\n+\n+\tcase AST::MetaItemInner::Kind::LitExpr:\n+\tdefault:\n+\t gcc_unreachable ();\n+\t break;\n+\t}\n+ }\n+}\n+\n+static void\n+check_link_section_attribute (const AST::Attribute &attribute)\n+{\n+ if (!attribute.has_attr_input ())\n+ {\n+ rust_error_at (attribute.get_locus (),\n+\t\t \"malformed % attribute input\");\n+ rust_inform (attribute.get_locus (),\n+\t\t \"must be of the form: %<#[link_section = \\\"name\\\"]%>\");\n+ }\n+}\n+\n+static void\n+check_export_name_attribute (const AST::Attribute &attribute)\n+{\n+ if (!attribute.has_attr_input ())\n+ {\n+ rust_error_at (attribute.get_locus (),\n+\t\t \"malformed % attribute input\");\n+ rust_inform (attribute.get_locus (),\n+\t\t \"must be of the form: %<#[export_name = \\\"name\\\"]%>\");\n+ return;\n+ }\n+\n+ auto &attr_input = attribute.get_attr_input ();\n+ if (attr_input.get_attr_input_type ()\n+ == AST::AttrInput::AttrInputType::LITERAL)\n+ {\n+ auto &literal_expr\n+\t= static_cast (attr_input).get_literal ();\n+ auto lit_type = literal_expr.get_lit_type ();\n+ switch (lit_type)\n+\t{\n+\tcase AST::Literal::LitType::STRING:\n+\tcase AST::Literal::LitType::RAW_STRING:\n+\tcase AST::Literal::LitType::BYTE_STRING:\n+\t return;\n+\tdefault:\n+\t break;\n+\t}\n+ }\n+\n+ rust_error_at (attribute.get_locus (), \"attribute must be a string literal\");\n+}\n+\n+static void\n+check_no_mangle_function (const AST::Attribute &attribute,\n+\t\t\t const AST::Function &fun)\n+{\n+ if (attribute.has_attr_input ())\n+ {\n+ rust_error_at (attribute.get_locus (), ErrorCode::E0754,\n+\t\t \"malformed % attribute input\");\n+ rust_inform (attribute.get_locus (),\n+\t\t \"must be of the form: %<#[no_mangle]%>\");\n+ }\n+ if (!is_ascii_only (fun.get_function_name ().as_string ()))\n+ rust_error_at (fun.get_function_name ().get_locus (),\n+\t\t \"the %<#[no_mangle]%> attribute requires ASCII identifier\");\n+}\n+\n+static void\n+check_lint_attribute (const AST::Attribute &attribute, const char *name)\n+{\n+ if (!attribute.has_attr_input ())\n+ {\n+ rust_error_at (attribute.get_locus (), \"malformed %qs attribute input\",\n+\t\t name);\n+ rust_inform (attribute.get_locus (),\n+\t\t \"must be of the form: %<#[%s(lint1, lint2, ...)]%>\", name);\n+ }\n+}\n+\n+/**\n+ * Emit an error when an attribute is attached\n+ * to an incompatable item type. e.g.:\n+ *\n+ * #[cold]\n+ * struct A(u8, u8);\n+ *\n+ * Note that \"#[derive]\" is handled\n+ * explicitly in rust-derive.cc\n+ */\n+static void\n+check_valid_attribute_for_item (const AST::Attribute &attr,\n+\t\t\t\tconst AST::Item &item)\n+{\n+ if (item.get_item_kind () != AST::Item::Kind::Function\n+ && (attr.get_path () == Values::Attributes::TARGET_FEATURE\n+\t || attr.get_path () == Values::Attributes::COLD\n+\t || attr.get_path () == Values::Attributes::INLINE))\n+ {\n+ rust_error_at (attr.get_locus (),\n+\t\t \"the %<#[%s]%> attribute may only be applied to functions\",\n+\t\t attr.get_path ().as_string ().c_str ());\n+ }\n+ else if (attr.get_path () == Values::Attributes::REPR\n+\t && item.get_item_kind () != AST::Item::Kind::Enum\n+\t && item.get_item_kind () != AST::Item::Kind::Union\n+\t && item.get_item_kind () != AST::Item::Kind::Struct)\n+ {\n+ rust_error_at (attr.get_locus (),\n+\t\t \"the %<#[%s]%> attribute may only be applied \"\n+\t\t \"to structs, enums and unions\",\n+\t\t attr.get_path ().as_string ().c_str ());\n+ }\n+}\n+\n+BuiltinAttributeChecker::BuiltinAttributeChecker () {}\n+\n+void\n+BuiltinAttributeChecker::go (AST::Crate &crate)\n+{\n+ visit (crate);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Crate &crate)\n+{\n+ for (auto &attr : crate.get_inner_attrs ())\n+ {\n+ check_inner_attribute (attr);\n+ }\n+\n+ AST::DefaultASTVisitor::visit (crate);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Attribute &attribute)\n+{\n+ if (auto builtin = lookup_builtin (attribute))\n+ {\n+ auto result = builtin.value ();\n+ // TODO: Add checks here for each builtin attribute\n+ // TODO: Have an enum of builtins as well, switching on strings is\n+ // annoying and costly\n+ if (result.name == Attrs::DOC)\n+\tcheck_doc_attribute (attribute);\n+ else if (result.name == Attrs::DEPRECATED)\n+\tcheck_deprecated_attribute (attribute);\n+ }\n+\n+ AST::DefaultASTVisitor::visit (attribute);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Module &module)\n+{\n+ for (auto &attr : module.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, module);\n+\n+ AST::DefaultASTVisitor::visit (module);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::ExternCrate &crate)\n+{\n+ for (auto &attr : crate.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, crate);\n+\n+ AST::DefaultASTVisitor::visit (crate);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::UseDeclaration &declaration)\n+{\n+ for (auto &attr : declaration.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, declaration);\n+\n+ AST::DefaultASTVisitor::visit (declaration);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Function &function)\n+{\n+ auto check_crate_type = [] (const char *name, AST::Attribute &attribute) {\n+ if (!Session::get_instance ().options.is_proc_macro ())\n+ rust_error_at (attribute.get_locus (),\n+\t\t \"the %<#[%s]%> attribute is only usable with crates of \"\n+\t\t \"the % crate type\",\n+\t\t name);\n+ };\n+\n+ BuiltinAttrDefinition result;\n+ for (auto &attribute : function.get_outer_attrs ())\n+ {\n+ check_valid_attribute_for_item (attribute, function);\n+\n+ auto result = lookup_builtin (attribute);\n+ if (!result)\n+\treturn;\n+\n+ auto name = result->name.c_str ();\n+\n+ if (result->name == Attrs::PROC_MACRO_DERIVE)\n+\t{\n+\t if (!attribute.has_attr_input ())\n+\t {\n+\t rust_error_at (attribute.get_locus (),\n+\t\t\t \"malformed %qs attribute input\", name);\n+\t rust_inform (\n+\t\tattribute.get_locus (),\n+\t\t\"must be of the form: %<#[proc_macro_derive(TraitName, \"\n+\t\t\"/*opt*/ attributes(name1, name2, ...))]%>\");\n+\t }\n+\t check_crate_type (name, attribute);\n+\t}\n+ else if (result->name == Attrs::PROC_MACRO\n+\t || result->name == Attrs::PROC_MACRO_ATTRIBUTE)\n+\t{\n+\t check_crate_type (name, attribute);\n+\t}\n+ else if (result->name == Attrs::TARGET_FEATURE)\n+\t{\n+\t if (!attribute.has_attr_input ())\n+\t {\n+\t rust_error_at (attribute.get_locus (),\n+\t\t\t \"malformed % attribute input\");\n+\t rust_inform (attribute.get_locus (),\n+\t\t\t \"must be of the form: %<#[target_feature(enable = \"\n+\t\t\t \"\\\"name\\\")]%>\");\n+\t }\n+\t else if (!function.get_qualifiers ().is_unsafe ())\n+\t {\n+\t rust_error_at (\n+\t\tattribute.get_locus (),\n+\t\t\"the %<#[target_feature]%> attribute can only be applied \"\n+\t\t\"to % functions\");\n+\t }\n+\t}\n+ else if (result->name == Attrs::NO_MANGLE)\n+\t{\n+\t if (attribute.has_attr_input ())\n+\t {\n+\t rust_error_at (attribute.get_locus (),\n+\t\t\t \"malformed % attribute input\");\n+\t rust_inform (attribute.get_locus (),\n+\t\t\t \"must be of the form: %<#[no_mangle]%>\");\n+\t }\n+\t else\n+\t check_no_mangle_function (attribute, function);\n+\t}\n+ else if (result->name == Attrs::EXPORT_NAME)\n+\t{\n+\t check_export_name_attribute (attribute);\n+\t}\n+ else if (result->name == Attrs::ALLOW || result->name == \"deny\"\n+\t || result->name == \"warn\" || result->name == \"forbid\")\n+\t{\n+\t check_lint_attribute (attribute, name);\n+\t}\n+ else if (result->name == Attrs::LINK_NAME)\n+\t{\n+\t if (!attribute.has_attr_input ())\n+\t {\n+\t rust_error_at (attribute.get_locus (),\n+\t\t\t \"malformed % attribute input\");\n+\t rust_inform (attribute.get_locus (),\n+\t\t\t \"must be of the form: %<#[link_name = \\\"name\\\"]%>\");\n+\t }\n+\t}\n+ else if (result->name == Attrs::LINK_SECTION)\n+\t{\n+\t check_link_section_attribute (attribute);\n+\t}\n+ }\n+\n+ AST::DefaultASTVisitor::visit (function);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::TypeAlias &alias)\n+{\n+ for (auto &attr : alias.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, alias);\n+\n+ AST::DefaultASTVisitor::visit (alias);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::StructStruct &struct_item)\n+{\n+ for (auto &attr : struct_item.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, struct_item);\n+\n+ AST::DefaultASTVisitor::visit (struct_item);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::TupleStruct &tuple_struct)\n+{\n+ for (auto &attr : tuple_struct.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, tuple_struct);\n+\n+ AST::DefaultASTVisitor::visit (tuple_struct);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Enum &enumeration)\n+{\n+ for (auto &attr : enumeration.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, enumeration);\n+\n+ AST::DefaultASTVisitor::visit (enumeration);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Union &u)\n+{\n+ for (auto &attr : u.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, u);\n+\n+ AST::DefaultASTVisitor::visit (u);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::ConstantItem &item)\n+{\n+ for (auto &attr : item.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, item);\n+\n+ AST::DefaultASTVisitor::visit (item);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::StaticItem &item)\n+{\n+ for (auto &attr : item.get_outer_attrs ())\n+ {\n+ check_valid_attribute_for_item (attr, item);\n+\n+ if (auto result = lookup_builtin (attr))\n+\t{\n+\t if (result->name == Attrs::LINK_SECTION)\n+\t check_link_section_attribute (attr);\n+\t else if (result->name == Attrs::EXPORT_NAME)\n+\t check_export_name_attribute (attr);\n+\t}\n+ }\n+\n+ AST::DefaultASTVisitor::visit (item);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::Trait &trait)\n+{\n+ for (auto &attr : trait.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, trait);\n+\n+ AST::DefaultASTVisitor::visit (trait);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::InherentImpl &impl)\n+{\n+ for (auto &attr : impl.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, impl);\n+\n+ AST::DefaultASTVisitor::visit (impl);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::TraitImpl &impl)\n+{\n+ for (auto &attr : impl.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, impl);\n+\n+ AST::DefaultASTVisitor::visit (impl);\n+}\n+\n+void\n+BuiltinAttributeChecker::visit (AST::ExternBlock &block)\n+{\n+ for (auto &attr : block.get_outer_attrs ())\n+ check_valid_attribute_for_item (attr, block);\n+\n+ AST::DefaultASTVisitor::visit (block);\n+}\n+\n+} // namespace Analysis\n+} // namespace Rust\ndiff --git a/gcc/rust/checks/errors/rust-builtin-attribute-checker.h b/gcc/rust/checks/errors/rust-builtin-attribute-checker.h\nnew file mode 100644\nindex 00000000000..6717de8abf6\n--- /dev/null\n+++ b/gcc/rust/checks/errors/rust-builtin-attribute-checker.h\n@@ -0,0 +1,58 @@\n+// Copyright (C) 2026 Free Software Foundation, Inc.\n+\n+// This file is part of GCC.\n+\n+// GCC is free software; you can redistribute it and/or modify it under\n+// the terms of the GNU General Public License as published by the Free\n+// Software Foundation; either version 3, or (at your option) any later\n+// version.\n+\n+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY\n+// WARRANTY; without even the implied warranty of MERCHANTABILITY or\n+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License\n+// for more details.\n+\n+// You should have received a copy of the GNU General Public License\n+// along with GCC; see the file COPYING3. If not see\n+// .\n+\n+#ifndef RUST_BUILTIN_ATTRIBUTE_CHECKER_H\n+#define RUST_BUILTIN_ATTRIBUTE_CHECKER_H\n+\n+#include \"rust-ast-visitor.h\"\n+\n+namespace Rust {\n+namespace Analysis {\n+\n+class BuiltinAttributeChecker : public AST::DefaultASTVisitor\n+{\n+ using AST::DefaultASTVisitor::visit;\n+\n+public:\n+ BuiltinAttributeChecker ();\n+ void go (AST::Crate &crate);\n+ void visit (AST::Crate &crate) override;\n+ void visit (AST::Attribute &attribute) override;\n+\n+ // Items\n+ void visit (AST::Module &module) override;\n+ void visit (AST::ExternCrate &crate) override;\n+ void visit (AST::UseDeclaration &use_decl) override;\n+ void visit (AST::Function &function) override;\n+ void visit (AST::TypeAlias &type_alias) override;\n+ void visit (AST::StructStruct &struct_item) override;\n+ void visit (AST::TupleStruct &tuple_struct) override;\n+ void visit (AST::Enum &enum_item) override;\n+ void visit (AST::Union &union_item) override;\n+ void visit (AST::ConstantItem &const_item) override;\n+ void visit (AST::StaticItem &static_item) override;\n+ void visit (AST::Trait &trait) override;\n+ void visit (AST::InherentImpl &impl) override;\n+ void visit (AST::TraitImpl &impl) override;\n+ void visit (AST::ExternBlock &block) override;\n+};\n+\n+} // namespace Analysis\n+} // namespace Rust\n+\n+#endif /* ! RUST_BUILTIN_ATTRIBUTE_CHECKER_H */\ndiff --git a/gcc/rust/hir/rust-ast-lower-base.cc b/gcc/rust/hir/rust-ast-lower-base.cc\nindex 8b2fa5a2f50..6fc4463a934 100644\n--- a/gcc/rust/hir/rust-ast-lower-base.cc\n+++ b/gcc/rust/hir/rust-ast-lower-base.cc\n@@ -832,13 +832,7 @@ void\n ASTLoweringBase::handle_doc_item_attribute (const ItemWrapper &,\n \t\t\t\t\t const AST::Attribute &attr)\n {\n- if (!attr.has_attr_input ())\n- {\n- rust_error_at (attr.get_locus (),\n-\t\t \"attribute must be of the form %qs or %qs\",\n-\t\t \"#[doc(hidden|inline|...)]\", \"#[doc = string]\");\n- return;\n- }\n+ rust_assert (attr.has_attr_input ());\n \n auto simple_doc_comment = attr.get_attr_input ().get_attr_input_type ()\n \t\t\t == AST::AttrInput::AttrInputType::LITERAL;\ndiff --git a/gcc/rust/rust-session-manager.cc b/gcc/rust/rust-session-manager.cc\nindex 12e076d1df0..364ca081142 100644\n--- a/gcc/rust/rust-session-manager.cc\n+++ b/gcc/rust/rust-session-manager.cc\n@@ -60,6 +60,7 @@\n #include \"rust-borrow-checker.h\"\n #include \"rust-ast-validation.h\"\n #include \"rust-tyty-variance-analysis.h\"\n+#include \"rust-builtin-attribute-checker.h\"\n \n #include \"input.h\"\n #include \"selftest.h\"\n@@ -735,6 +736,8 @@ Session::compile_crate (const char *filename)\n \n expansion (parsed_crate, name_resolution_ctx);\n \n+ Analysis::BuiltinAttributeChecker ().go (parsed_crate);\n+\n AST::CollectLangItems ().go (parsed_crate);\n \n rust_debug (\"\\033[0;31mSUCCESSFULLY FINISHED EXPANSION \\033[0m\");\ndiff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc\nindex 3b6587ffdaa..f03fa90d9c0 100644\n--- a/gcc/rust/util/rust-attributes.cc\n+++ b/gcc/rust/util/rust-attributes.cc\n@@ -29,40 +29,6 @@\n namespace Rust {\n namespace Analysis {\n \n-bool\n-Attributes::is_known (const std::string &attribute_path)\n-{\n- const auto &lookup\n- = BuiltinAttributeMappings::get ()->lookup_builtin (attribute_path);\n-\n- return !lookup.is_error ();\n-}\n-\n-tl::optional\n-Attributes::extract_string_literal (const AST::Attribute &attr)\n-{\n- if (!attr.has_attr_input ())\n- return tl::nullopt;\n-\n- auto &attr_input = attr.get_attr_input ();\n-\n- if (attr_input.get_attr_input_type ()\n- != AST::AttrInput::AttrInputType::LITERAL)\n- return tl::nullopt;\n-\n- auto &literal_expr\n- = static_cast (attr_input).get_literal ();\n-\n- auto lit_type = literal_expr.get_lit_type ();\n-\n- // TODO: bring escape sequence handling out of lexing?\n- if (lit_type != AST::Literal::LitType::STRING\n- && lit_type != AST::Literal::LitType::RAW_STRING)\n- return tl::nullopt;\n-\n- return literal_expr.as_string ();\n-}\n-\n using Attrs = Values::Attributes;\n \n // https://doc.rust-lang.org/stable/nightly-rustc/src/rustc_feature/builtin_attrs.rs.html#248\n@@ -151,6 +117,45 @@ static const std::set __outer_attributes\n Attrs::LINK_NAME,\n Attrs::LINK_SECTION};\n \n+bool\n+Attributes::is_known (const std::string &attribute_path)\n+{\n+ const auto &lookup\n+ = BuiltinAttributeMappings::get ()->lookup_builtin (attribute_path);\n+\n+ return !lookup.is_error ();\n+}\n+\n+bool\n+Attributes::valid_outer_attribute (const std::string &attribute_path)\n+{\n+ return __outer_attributes.find (attribute_path) != __outer_attributes.cend ();\n+}\n+\n+tl::optional\n+Attributes::extract_string_literal (const AST::Attribute &attr)\n+{\n+ if (!attr.has_attr_input ())\n+ return tl::nullopt;\n+\n+ auto &attr_input = attr.get_attr_input ();\n+\n+ if (attr_input.get_attr_input_type ()\n+ != AST::AttrInput::AttrInputType::LITERAL)\n+ return tl::nullopt;\n+\n+ auto &literal_expr\n+ = static_cast (attr_input).get_literal ();\n+\n+ auto lit_type = literal_expr.get_lit_type ();\n+\n+ // TODO: bring escape sequence handling out of lexing?\n+ if (lit_type != AST::Literal::LitType::STRING\n+ && lit_type != AST::Literal::LitType::RAW_STRING)\n+ return tl::nullopt;\n+\n+ return literal_expr.as_string ();\n+}\n BuiltinAttributeMappings *\n BuiltinAttributeMappings::get ()\n {\n@@ -189,20 +194,8 @@ AttributeChecker::go (AST::Crate &crate)\n visit (crate);\n }\n \n-void\n-AttributeChecker::visit (AST::Crate &crate)\n-{\n- for (auto &attr : crate.get_inner_attrs ())\n- {\n- check_inner_attribute (attr);\n- }\n-\n- for (auto &item : crate.items)\n- item->accept_vis (*this);\n-}\n-\n tl::optional\n-identify_builtin (const AST::Attribute &attribute)\n+lookup_builtin (const AST::Attribute &attribute)\n {\n auto &segments = attribute.get_path ().get_segments ();\n \n@@ -216,224 +209,10 @@ identify_builtin (const AST::Attribute &attribute)\n segments.at (0).get_segment_name ());\n }\n \n-/**\n- * Check that the string given to #[doc(alias = ...)] or #[doc(alias(...))] is\n- * valid.\n- *\n- * This means no whitespace characters other than spaces and no quoting\n- * characters.\n- */\n-static void\n-check_doc_alias (const std::string &alias_input, const location_t locus)\n-{\n- // FIXME: The locus here is for the whole attribute. Can we get the locus\n- // of the alias input instead?\n- for (auto c : alias_input)\n- if ((ISSPACE (c) && c != ' ') || c == '\\'' || c == '\\\"')\n- {\n-\tauto to_print = std::string (1, c);\n-\tswitch (c)\n-\t {\n-\t case '\\n':\n-\t to_print = \"\\\\n\";\n-\t break;\n-\t case '\\t':\n-\t to_print = \"\\\\t\";\n-\t break;\n-\t default:\n-\t break;\n-\t }\n-\trust_error_at (locus,\n-\t\t \"invalid character used in %<#[doc(alias)]%> input: %qs\",\n-\t\t to_print.c_str ());\n- }\n-\n- if (alias_input.empty ())\n- return;\n-\n- if (alias_input.front () == ' ' || alias_input.back () == ' ')\n- rust_error_at (locus,\n-\t\t \"%<#[doc(alias)]%> input cannot start or end with a space\");\n-}\n-\n-static void\n-check_doc_attribute (const AST::Attribute &attribute)\n-{\n- if (!attribute.has_attr_input ())\n- {\n- rust_error_at (\n-\tattribute.get_locus (),\n-\t\"valid forms for the attribute are \"\n-\t\"%<#[doc(hidden|inline|...)]%> and %<#[doc = \\\" string \\\"]%>\");\n- return;\n- }\n-\n- switch (attribute.get_attr_input ().get_attr_input_type ())\n- {\n- case AST::AttrInput::LITERAL:\n- case AST::AttrInput::META_ITEM:\n- case AST::AttrInput::EXPR:\n- break;\n- // FIXME: Handle them as well\n-\n- case AST::AttrInput::TOKEN_TREE:\n- {\n-\t// FIXME: This doesn't check for #[doc(alias(...))]\n-\tconst auto &option = static_cast (\n-\t attribute.get_attr_input ());\n-\tauto *meta_item = option.parse_to_meta_item ();\n-\n-\tfor (auto &item : meta_item->get_items ())\n-\t {\n-\t if (item->is_key_value_pair ())\n-\t {\n-\t\tauto name_value\n-\t\t = static_cast (item.get ())\n-\t\t ->get_name_value_pair ();\n-\n-\t\t// FIXME: Check for other stuff than #[doc(alias = ...)]\n-\t\tif (name_value.first.as_string () == \"alias\")\n-\t\t check_doc_alias (name_value.second, attribute.get_locus ());\n-\t }\n-\t }\n-\tbreak;\n- }\n- }\n-}\n-\n-static void\n-check_deprecated_attribute (const AST::Attribute &attribute)\n-{\n- if (!attribute.has_attr_input ())\n- return;\n-\n- const auto &input = attribute.get_attr_input ();\n-\n- if (input.get_attr_input_type () != AST::AttrInput::META_ITEM)\n- return;\n-\n- auto &meta = static_cast (input);\n-\n- for (auto ¤t : meta.get_items ())\n- {\n- switch (current->get_kind ())\n-\t{\n-\tcase AST::MetaItemInner::Kind::MetaItem:\n-\t {\n-\t auto *meta_item = static_cast (current.get ());\n-\n-\t switch (meta_item->get_item_kind ())\n-\t {\n-\t case AST::MetaItem::ItemKind::NameValueStr:\n-\t\t{\n-\t\t auto *nv = static_cast (meta_item);\n-\n-\t\t const std::string key = nv->get_name ().as_string ();\n-\n-\t\t if (key != \"since\" && key != \"note\")\n-\t\t {\n-\t\t rust_error_at (nv->get_locus (), \"unknown meta item %qs\",\n-\t\t\t\t key.c_str ());\n-\t\t rust_inform (nv->get_locus (),\n-\t\t\t\t \"expected one of %, %\");\n-\t\t }\n-\t\t}\n-\t\tbreak;\n-\n-\t case AST::MetaItem::ItemKind::Path:\n-\t\t{\n-\t\t // #[deprecated(a,a)]\n-\t\t auto *p = static_cast (meta_item);\n-\n-\t\t std::string ident = p->get_path ().as_string ();\n-\n-\t\t rust_error_at (p->get_locus (), \"unknown meta item %qs\",\n-\t\t\t\t ident.c_str ());\n-\t\t rust_inform (p->get_locus (),\n-\t\t\t \"expected one of %, %\");\n-\t\t}\n-\t\tbreak;\n-\n-\t case AST::MetaItem::ItemKind::Word:\n-\t\t{\n-\t\t // #[deprecated(\"a\")]\n-\t\t auto *w = static_cast (meta_item);\n-\n-\t\t rust_error_at (\n-\t\t w->get_locus (),\n-\t\t \"item in % must be a key/value pair\");\n-\t\t}\n-\t\tbreak;\n-\n-\t case AST::MetaItem::ItemKind::PathExpr:\n-\t\t{\n-\t\t // #[deprecated(since=a)]\n-\t\t auto *px = static_cast (meta_item);\n-\n-\t\t rust_error_at (\n-\t\t px->get_locus (),\n-\t\t \"expected unsuffixed literal or identifier, found %qs\",\n-\t\t px->get_expr ().as_string ().c_str ());\n-\t\t}\n-\t\tbreak;\n-\n-\t case AST::MetaItem::ItemKind::Seq:\n-\t case AST::MetaItem::ItemKind::ListPaths:\n-\t case AST::MetaItem::ItemKind::ListNameValueStr:\n-\t default:\n-\t\tgcc_unreachable ();\n-\t\tbreak;\n-\t }\n-\t }\n-\t break;\n-\n-\tcase AST::MetaItemInner::Kind::LitExpr:\n-\tdefault:\n-\t gcc_unreachable ();\n-\t break;\n-\t}\n- }\n-}\n-\n-/**\n- * Emit an error when an attribute is attached\n- * to an incompatable item type. e.g.:\n- *\n- * #[cold]\n- * struct A(u8, u8);\n- *\n- * Note that \"#[derive]\" is handled\n- * explicitly in rust-derive.cc\n- */\n-static void\n-check_valid_attribute_for_item (const AST::Attribute &attr,\n-\t\t\t\tconst AST::Item &item)\n-{\n- if (item.get_item_kind () != AST::Item::Kind::Function\n- && (attr.get_path () == Values::Attributes::TARGET_FEATURE\n-\t || attr.get_path () == Values::Attributes::COLD\n-\t || attr.get_path () == Values::Attributes::INLINE))\n- {\n- rust_error_at (attr.get_locus (),\n-\t\t \"the %<#[%s]%> attribute may only be applied to functions\",\n-\t\t attr.get_path ().as_string ().c_str ());\n- }\n- else if (attr.get_path () == Values::Attributes::REPR\n-\t && item.get_item_kind () != AST::Item::Kind::Enum\n-\t && item.get_item_kind () != AST::Item::Kind::Union\n-\t && item.get_item_kind () != AST::Item::Kind::Struct)\n- {\n- rust_error_at (attr.get_locus (),\n-\t\t \"the %<#[%s]%> attribute may only be applied \"\n-\t\t \"to structs, enums and unions\",\n-\t\t attr.get_path ().as_string ().c_str ());\n- }\n-}\n-\n static bool\n is_proc_macro_type (const AST::Attribute &attribute)\n {\n- auto result_opt = identify_builtin (attribute);\n+ auto result_opt = lookup_builtin (attribute);\n if (!result_opt.has_value ())\n return false;\n auto result = result_opt.value ();\n@@ -469,77 +248,6 @@ check_proc_macro_non_root (const AST::Attribute &attr, location_t loc)\n }\n }\n \n-void\n-AttributeChecker::check_inner_attribute (const AST::Attribute &attribute)\n-{\n- auto result_opt = identify_builtin (attribute);\n- if (!result_opt.has_value ())\n- return;\n- auto result = result_opt.value ();\n-\n- if (__outer_attributes.find (result.name) != __outer_attributes.end ())\n- rust_error_at (attribute.get_locus (),\n-\t\t \"attribute cannot be used at crate level\");\n-}\n-\n-static void\n-check_link_section_attribute (const AST::Attribute &attribute)\n-{\n- if (!attribute.has_attr_input ())\n- {\n- rust_error_at (attribute.get_locus (),\n-\t\t \"malformed % attribute input\");\n- rust_inform (attribute.get_locus (),\n-\t\t \"must be of the form: %<#[link_section = \\\"name\\\"]%>\");\n- }\n-}\n-\n-static void\n-check_export_name_attribute (const AST::Attribute &attribute)\n-{\n- if (!attribute.has_attr_input ())\n- {\n- rust_error_at (attribute.get_locus (),\n-\t\t \"malformed % attribute input\");\n- rust_inform (attribute.get_locus (),\n-\t\t \"must be of the form: %<#[export_name = \\\"name\\\"]%>\");\n- return;\n- }\n-\n- if (attribute.has_attr_input ())\n- {\n- auto &attr_input = attribute.get_attr_input ();\n- if (attr_input.get_attr_input_type ()\n-\t == AST::AttrInput::AttrInputType::LITERAL)\n-\t{\n-\t auto &literal_expr\n-\t = static_cast (attr_input).get_literal ();\n-\t auto lit_type = literal_expr.get_lit_type ();\n-\t switch (lit_type)\n-\t {\n-\t case AST::Literal::LitType::STRING:\n-\t case AST::Literal::LitType::RAW_STRING:\n-\t case AST::Literal::LitType::BYTE_STRING:\n-\t return;\n-\t default:\n-\t break;\n-\t }\n-\t}\n- }\n-}\n-\n-static void\n-check_lint_attribute (const AST::Attribute &attribute, const char *name)\n-{\n- if (!attribute.has_attr_input ())\n- {\n- rust_error_at (attribute.get_locus (), \"malformed %qs attribute input\",\n-\t\t name);\n- rust_inform (attribute.get_locus (),\n-\t\t \"must be of the form: %<#[%s(lint1, lint2, ...)]%>\", name);\n- }\n-}\n-\n void\n AttributeChecker::visit (AST::Attribute &attribute)\n {\n@@ -552,18 +260,6 @@ AttributeChecker::visit (AST::Attribute &attribute)\n \treturn; // Do not emit errors for attribute that'll get stripped.\n }\n \n- if (auto builtin = identify_builtin (attribute))\n- {\n- auto result = builtin.value ();\n- // TODO: Add checks here for each builtin attribute\n- // TODO: Have an enum of builtins as well, switching on strings is\n- // annoying and costly\n- if (result.name == Attrs::DOC)\n-\tcheck_doc_attribute (attribute);\n- else if (result.name == Attrs::DEPRECATED)\n-\tcheck_deprecated_attribute (attribute);\n- }\n-\n AST::DefaultASTVisitor::visit (attribute);\n }\n \n@@ -870,10 +566,7 @@ void\n AttributeChecker::visit (AST::Module &module)\n {\n for (auto &attr : module.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, module);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n \n for (auto &item : module.get_items ())\n for (auto &attr : item->get_outer_attrs ())\n@@ -886,10 +579,7 @@ void\n AttributeChecker::visit (AST::ExternCrate &crate)\n {\n for (auto &attr : crate.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, crate);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n@@ -908,124 +598,12 @@ void\n AttributeChecker::visit (AST::UseDeclaration &declaration)\n {\n for (auto &attr : declaration.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, declaration);\n- check_proc_macro_non_function (attr);\n- }\n-}\n-\n-static void\n-check_no_mangle_function (const AST::Attribute &attribute,\n-\t\t\t const AST::Function &fun)\n-{\n- if (attribute.has_attr_input ())\n- {\n- rust_error_at (attribute.get_locus (), ErrorCode::E0754,\n-\t\t \"malformed % attribute input\");\n- rust_inform (attribute.get_locus (),\n-\t\t \"must be of the form: %<#[no_mangle]%>\");\n- }\n- if (!is_ascii_only (fun.get_function_name ().as_string ()))\n- rust_error_at (fun.get_function_name ().get_locus (),\n-\t\t \"the %<#[no_mangle]%> attribute requires ASCII identifier\");\n+ check_proc_macro_non_function (attr);\n }\n \n void\n AttributeChecker::visit (AST::Function &fun)\n {\n- for (auto &attr : fun.get_outer_attrs ())\n- check_valid_attribute_for_item (attr, fun);\n-\n- auto check_crate_type = [] (const char *name, AST::Attribute &attribute) {\n- if (!Session::get_instance ().options.is_proc_macro ())\n- rust_error_at (attribute.get_locus (),\n-\t\t \"the %<#[%s]%> attribute is only usable with crates of \"\n-\t\t \"the % crate type\",\n-\t\t name);\n- };\n-\n- BuiltinAttrDefinition result;\n- for (auto &attribute : fun.get_outer_attrs ())\n- {\n- auto result = identify_builtin (attribute);\n- if (!result)\n-\treturn;\n-\n- auto name = result->name.c_str ();\n-\n- if (result->name == Attrs::PROC_MACRO_DERIVE)\n-\t{\n-\t if (!attribute.has_attr_input ())\n-\t {\n-\t rust_error_at (attribute.get_locus (),\n-\t\t\t \"malformed %qs attribute input\", name);\n-\t rust_inform (\n-\t\tattribute.get_locus (),\n-\t\t\"must be of the form: %<#[proc_macro_derive(TraitName, \"\n-\t\t\"/*opt*/ attributes(name1, name2, ...))]%>\");\n-\t }\n-\t check_crate_type (name, attribute);\n-\t}\n- else if (result->name == Attrs::PROC_MACRO\n-\t || result->name == Attrs::PROC_MACRO_ATTRIBUTE)\n-\t{\n-\t check_crate_type (name, attribute);\n-\t}\n- else if (result->name == Attrs::TARGET_FEATURE)\n-\t{\n-\t if (!attribute.has_attr_input ())\n-\t {\n-\t rust_error_at (attribute.get_locus (),\n-\t\t\t \"malformed % attribute input\");\n-\t rust_inform (attribute.get_locus (),\n-\t\t\t \"must be of the form: %<#[target_feature(enable = \"\n-\t\t\t \"\\\"name\\\")]%>\");\n-\t }\n-\t else if (!fun.get_qualifiers ().is_unsafe ())\n-\t {\n-\t rust_error_at (\n-\t\tattribute.get_locus (),\n-\t\t\"the %<#[target_feature]%> attribute can only be applied \"\n-\t\t\"to % functions\");\n-\t }\n-\t}\n- else if (result->name == Attrs::NO_MANGLE)\n-\t{\n-\t if (attribute.has_attr_input ())\n-\t {\n-\t rust_error_at (attribute.get_locus (),\n-\t\t\t \"malformed % attribute input\");\n-\t rust_inform (attribute.get_locus (),\n-\t\t\t \"must be of the form: %<#[no_mangle]%>\");\n-\t }\n-\t else\n-\t check_no_mangle_function (attribute, fun);\n-\t}\n- else if (result->name == Attrs::EXPORT_NAME)\n-\t{\n-\t check_export_name_attribute (attribute);\n-\t}\n- else if (result->name == Attrs::ALLOW || result->name == \"deny\"\n-\t || result->name == \"warn\" || result->name == \"forbid\")\n-\t{\n-\t check_lint_attribute (attribute, name);\n-\t}\n- else if (result->name == Attrs::LINK_NAME)\n-\t{\n-\t if (!attribute.has_attr_input ())\n-\t {\n-\t rust_error_at (attribute.get_locus (),\n-\t\t\t \"malformed % attribute input\");\n-\t rust_inform (attribute.get_locus (),\n-\t\t\t \"must be of the form: %<#[link_name = \\\"name\\\"]%>\");\n-\t }\n-\t}\n- else if (result->name == Attrs::LINK_SECTION)\n-\t{\n-\t check_link_section_attribute (attribute);\n-\t}\n- }\n-\n if (fun.has_body ())\n fun.get_definition ().value ()->accept_vis (*this);\n }\n@@ -1034,10 +612,7 @@ void\n AttributeChecker::visit (AST::TypeAlias &alias)\n {\n for (auto &attr : alias.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, alias);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n@@ -1045,7 +620,6 @@ AttributeChecker::visit (AST::StructStruct &struct_item)\n {\n for (auto &attr : struct_item.get_outer_attrs ())\n {\n- check_valid_attribute_for_item (attr, struct_item);\n check_proc_macro_non_function (attr);\n }\n \n@@ -1056,10 +630,7 @@ void\n AttributeChecker::visit (AST::TupleStruct &tuplestruct)\n {\n for (auto &attr : tuplestruct.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, tuplestruct);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n@@ -1082,48 +653,28 @@ void\n AttributeChecker::visit (AST::Enum &enumeration)\n {\n for (auto &attr : enumeration.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, enumeration);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n AttributeChecker::visit (AST::Union &u)\n {\n for (auto &attr : u.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, u);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n AttributeChecker::visit (AST::ConstantItem &item)\n {\n for (auto &attr : item.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, item);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n AttributeChecker::visit (AST::StaticItem &item)\n {\n for (auto &attr : item.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, item);\n- check_proc_macro_non_function (attr);\n-\n- if (auto result = identify_builtin (attr))\n-\t{\n-\t if (result->name == Attrs::LINK_SECTION)\n-\t check_link_section_attribute (attr);\n-\t else if (result->name == Attrs::EXPORT_NAME)\n-\t check_export_name_attribute (attr);\n-\t}\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n void\n@@ -1134,10 +685,8 @@ void\n AttributeChecker::visit (AST::Trait &trait)\n {\n for (auto &attr : trait.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, trait);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n+\n AST::DefaultASTVisitor::visit (trait);\n }\n \n@@ -1145,10 +694,7 @@ void\n AttributeChecker::visit (AST::InherentImpl &impl)\n {\n for (auto &attr : impl.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, impl);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n \n AST::DefaultASTVisitor::visit (impl);\n }\n@@ -1157,10 +703,8 @@ void\n AttributeChecker::visit (AST::TraitImpl &impl)\n {\n for (auto &attr : impl.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, impl);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n+\n AST::DefaultASTVisitor::visit (impl);\n }\n \n@@ -1176,10 +720,7 @@ void\n AttributeChecker::visit (AST::ExternBlock &block)\n {\n for (auto &attr : block.get_outer_attrs ())\n- {\n- check_valid_attribute_for_item (attr, block);\n- check_proc_macro_non_function (attr);\n- }\n+ check_proc_macro_non_function (attr);\n }\n \n // rust-macro.h\ndiff --git a/gcc/rust/util/rust-attributes.h b/gcc/rust/util/rust-attributes.h\nindex 4bac820120c..3e5aea815e8 100644\n--- a/gcc/rust/util/rust-attributes.h\n+++ b/gcc/rust/util/rust-attributes.h\n@@ -29,6 +29,7 @@ class Attributes\n {\n public:\n static bool is_known (const std::string &attribute_path);\n+ static bool valid_outer_attribute (const std::string &attribute_path);\n static tl::optional\n extract_string_literal (const AST::Attribute &attr);\n };\n@@ -109,7 +110,6 @@ private:\n \n // rust-ast.h\n void visit (AST::Attribute &attribute) override;\n- void visit (AST::Crate &crate) override;\n void visit (AST::Token &tok) override;\n void visit (AST::DelimTokenTree &delim_tok_tree) override;\n void visit (AST::IdentifierExpr &ident_expr) override;\n@@ -277,7 +277,7 @@ private:\n };\n \n tl::optional\n-identify_builtin (const AST::Attribute &attribute);\n+lookup_builtin (const AST::Attribute &attribute);\n \n } // namespace Analysis\n } // namespace Rust\ndiff --git a/gcc/testsuite/rust/compile/issue-4226.rs b/gcc/testsuite/rust/compile/issue-4226.rs\nindex ec49606cfac..e0763eca02d 100644\n--- a/gcc/testsuite/rust/compile/issue-4226.rs\n+++ b/gcc/testsuite/rust/compile/issue-4226.rs\n@@ -1,6 +1,6 @@\n #![feature(no_core)]\n #![no_core]\n \n+// { dg-error \"valid forms for the attribute are ...doc.hidden.inline....... and ...doc ... string ...\" \"\" { target *-*-* } .+1 }\n #[doc]\n-// { dg-error \"attribute must be of the form ...doc.hidden.inline....... or ...doc = string..\" \"\" { target *-*-* } .-1 }\n-pub fn a(){}\n+pub fn a() {}\n","prefixes":["COMMITTED","22/43"]}