Merge #1040

1040: Do not propagate parse errors in match repetitions r=CohenArthur a=CohenArthur

Since parsing repetitions is very eager, the parser might accumulate
bogus errors by trying to match more repetitions than there are. We can
avoid this by clearing the parsing errors if parsing repetitions
returned a valid result. This should not be an issue for previous
matchers erroring out, as they would immediately return upon failure and
not reach inside other match functions.

We need to figure out the best way to emit parser errors, as we do not always want to emit them in `match_fragment`. I think for now the easiest is to just *not* emit parse errors and simply error out with "failed to match macro rule". We will need to think about adding a bunch of hints too in order to make using macros easier.

Fixes #958 

Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index 5880616..9a31fb6 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -649,7 +649,6 @@ private:
   bool done_end_of_file ();
 
   void add_error (Error error) { error_table.push_back (std::move (error)); }
-  void clear_errors () { error_table.clear (); }
 
 public:
   // Construct parser with specified "managed" token source.
@@ -668,6 +667,8 @@ public:
 
   // Returns whether any parsing errors have occurred.
   bool has_errors () const { return !error_table.empty (); }
+  // Remove all parsing errors from the table
+  void clear_errors () { error_table.clear (); }
 
   // Get a reference to the list of errors encountered
   std::vector<Error> &get_errors () { return error_table; }