Reduce usage of rust-session-manager.h

gcc/rust/ChangeLog:

	* util/rust-edition.cc: New file.
	* util/rust-edition.h: New file.
	* Make-lang.in: Add rust-edition.o to the object list.

	* ast/rust-pattern.cc: Remove inclusion of
	rust-session-manager.h.
	* expand/rust-macro-expand.cc: Likewise.
	* expand/rust-macro-builtins-helpers.h: Likewise.

	* expand/rust-macro-builtins-include.cc: Include
	rust-session-manager.h.
	* expand/rust-macro-builtins-utility.cc: Likewise.

	* lex/rust-lex.cc: Include rust-edition.h instead of
	rust-session-manager.h.
	(Lexer::classify_keyword): Use get_rust_edition instead of
	Session and CompileOptions.

	* parse/rust-parse-impl.h: Include rust-edition.h instead of
	rust-session-manager.h.
	(Parser::parse_async_item): Use get_rust_edition instead of
	Session and CompileOptions.

	* checks/errors/rust-feature.h: Include rust-edition.h instead
	of rust-session-manager.h.
	(class Feature): Use Rust::Edition instead of
	Rust::CompileOptions::Edition.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

2 files changed, 81 insertions, 0 deletions

diff --git a/gcc/rust/util/rust-edition.cc b/gcc/rust/util/rust-edition.cc
new file mode 100644
index 0000000..4e44a91
--- /dev/null
+++ b/gcc/rust/util/rust-edition.cc
@@ -0,0 +1,40 @@
+// Copyright (C) 2025 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-edition.h"
+#include "rust-session-manager.h"
+
+namespace Rust {
+
+Edition
+get_rust_edition ()
+{
+  switch (Session::get_instance ().options.get_edition ())
+    {
+    case CompileOptions::Edition::E2015:
+      return Edition::E2015;
+    case CompileOptions::Edition::E2018:
+      return Edition::E2018;
+    case CompileOptions::Edition::E2021:
+      return Edition::E2021;
+    default:
+      rust_unreachable ();
+    }
+}
+
+} // namespace Rust
diff --git a/gcc/rust/util/rust-edition.h b/gcc/rust/util/rust-edition.h
new file mode 100644
index 0000000..d034ea0
--- /dev/null
+++ b/gcc/rust/util/rust-edition.h
@@ -0,0 +1,41 @@
+// Copyright (C) 2025 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_EDITION_H
+#define RUST_EDITION_H
+
+/*
+ * This header exists to avoid including rust-session-manager.h
+ * when we only need information on the selected rust edition
+ */
+
+namespace Rust {
+
+enum class Edition
+{
+  E2015,
+  E2018,
+  E2021
+};
+
+Edition
+get_rust_edition ();
+
+} // namespace Rust
+
+#endif // !RUST_EDITION_H