Report self parameter parsing error kind

Self parameter parsing errors may come from different situations, which
should not be handled in the same way. It is now possible to
differentiate a missing self parameter from a self pointer or a parsing
error.

gcc/rust/ChangeLog:

	* parse/rust-parse-impl.h (Parser::parse_function): Early return on
	unrecoverable errors.
	(Parser::parse_trait_item): Likewise.
	(Parser::parse_self_param): Update return type.
	* parse/rust-parse.h (enum ParseSelfError): Add enumeration to describe
	different self parameter parsing errors.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index 08e6ce0..e873d52 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -22,6 +22,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "rust-ast-full.h"
 #include "rust-diagnostics.h"
 
+#include "expected.h"
+
 namespace Rust {
 /* HACK: used to resolve the expression-or-statement problem at the end of a
  * block by allowing either to be returned (technically). Tagged union would
@@ -93,6 +95,12 @@ struct ParseRestrictions
   bool allow_close_after_expr_stmt = false;
 };
 
+enum ParseSelfError
+{
+  SELF_PTR,
+  PARSING,
+  NOT_SELF,
+};
 // Parser implementation for gccrs.
 // TODO: if updated to C++20, ManagedTokenSource would be useful as a concept
 template <typename ManagedTokenSource> class Parser
@@ -335,7 +343,9 @@ private:
   parse_trait_type (AST::AttrVec outer_attrs, AST::Visibility);
   std::unique_ptr<AST::TraitItemConst>
   parse_trait_const (AST::AttrVec outer_attrs);
-  std::unique_ptr<AST::Param> parse_self_param ();
+
+  tl::expected<std::unique_ptr<AST::Param>, ParseSelfError> parse_self_param ();
+
   std::unique_ptr<AST::Impl> parse_impl (AST::Visibility vis,
 					 AST::AttrVec outer_attrs);
   std::unique_ptr<AST::InherentImplItem>