[3.9] bpo-42123: Run the parser two times and only enable invalid rules on the second run (GH-22111) (GH-23011)

* Implement running the parser a second time for the errors messages

The first parser run is only responsible for detecting whether
there is a `SyntaxError` or not. If there isn't the AST gets returned.
Otherwise, the parser is run a second time with all the `invalid_*`
rules enabled so that all the customized error messages get produced.

(cherry picked from commit bca701403253379409dece03053dbd739c0bd059)

1 files changed, 2 insertions, 2 deletions

diff --git a/Grammar/python.gram b/Grammar/python.gram
index 6c36b6a..b709d3d 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -535,7 +535,7 @@ yield_expr[expr_ty]:
 
 arguments[expr_ty] (memo):
     | a=args [','] &')' { a }
-    | incorrect_arguments
+    | invalid_arguments
 args[expr_ty]:
     | a=','.(starred_expression | named_expression !'=')+ b=[',' k=kwargs {k}] { _PyPegen_collect_call_seqs(p, a, b, EXTRA) }
     | a=kwargs { _Py_Call(_PyPegen_dummy_name(p),
@@ -620,7 +620,7 @@ t_atom[expr_ty]:
 
 
 # From here on, there are rules for invalid syntax with specialised error messages
-incorrect_arguments:
+invalid_arguments:
     | args ',' '*' { RAISE_SYNTAX_ERROR("iterable argument unpacking follows keyword argument unpacking") }
     | a=expression for_if_clauses ',' [args | expression for_if_clauses] {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "Generator expression must be parenthesized") }