ast: Add base nodes for FormatArgs

This commit adds a base for creating AST FormatArgs nodes after expanding
invocations of `format_args!()`. These nodes will then be expanded to
the proper runtime function calls (to core::fmt::rt) during the AST
lowering.

gcc/rust/ChangeLog:

	* ast/rust-builtin-ast-nodes.h: New file.
	* ast/rust-ast-full-decls.h (class FormatArgs): Declare new class.
	* ast/rust-ast-collector.cc: Handle FormatArgs nodes properly.
	* ast/rust-ast-collector.h: Likewise.
	* ast/rust-ast-full.h: Likewise.
	* ast/rust-ast-visitor.cc: Likewise.
	* ast/rust-ast-visitor.h: Likewise.
	* ast/rust-ast.cc: Likewise.
	* ast/rust-ast.h: Likewise.
	* expand/rust-derive.h: Likewise.
	* hir/rust-ast-lower-base.cc: Likewise.
	* hir/rust-ast-lower-base.h: Likewise.
	* hir/rust-ast-lower-expr.cc: Likewise.
	* hir/rust-ast-lower-expr.h: Likewise.
	* resolve/rust-ast-resolve-base.cc: Likewise.
	* resolve/rust-ast-resolve-base.h: Likewise.

1 files changed, 1 insertions, 0 deletions

diff --git a/gcc/rust/expand/rust-derive.h b/gcc/rust/expand/rust-derive.h
index 8fe29c0..f953c3d 100644
--- a/gcc/rust/expand/rust-derive.h
+++ b/gcc/rust/expand/rust-derive.h
@@ -221,6 +221,7 @@ private:
   virtual void visit (SelfParam &param) override final{};
   virtual void visit (FunctionParam &param) override final{};
   virtual void visit (VariadicParam &param) override final{};
+  virtual void visit (FormatArgs &param) override final{};
 };
 
 } // namespace AST