[gcc r13-5542] gccrs: transcriber: Do not infinite loop if the current parsed node is an error

[Arthur Cohen <cohenarthur@gcc.gnu.org>]

https://gcc.gnu.org/g:252216dd0c5956dfb931031fd1f8dfa59c922160

commit r13-5542-g252216dd0c5956dfb931031fd1f8dfa59c922160
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Mon Aug 29 16:23:51 2022 +0200

    gccrs: transcriber: Do not infinite loop if the current parsed node is an error
    
    gcc/rust/ChangeLog:
    
            * expand/rust-macro-expand.cc (parse_many): Return early from parsing
            loop if we encounter an error, and emit that error in the meantime.
    
    Co-authored-by: philberty <philip.herron@embecosm.com>

Diff:
---
 gcc/rust/expand/rust-macro-expand.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gcc/rust/expand/rust-macro-expand.cc b/gcc/rust/expand/rust-macro-expand.cc
index df258bd96ec..ed1b838c987 100644
--- a/gcc/rust/expand/rust-macro-expand.cc
+++ b/gcc/rust/expand/rust-macro-expand.cc
@@ -731,6 +731,14 @@ parse_many (Parser<MacroInvocLexer> &parser, TokenId &delimiter,
 	break;
 
       auto node = parse_fn ();
+      if (node.is_error ())
+	{
+	  for (auto err : parser.get_errors ())
+	    err.emit_error ();
+
+	  return AST::ASTFragment::create_error ();
+	}
+
       nodes.emplace_back (std::move (node));
     }