bpo-40334: Produce better error messages for non-parenthesized genexps (GH-20153)
The error message, generated for a non-parenthesized generator expression
in function calls, was still the generic `invalid syntax`, when the generator expression wasn't appearing as the first argument in the call. With this patch, even on input like `f(a, b, c for c in d, e)`, the correct error message gets produced.
(cherry picked from commit ae145833025b0156ee2a28219e3370f3b27b2a36)
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
diff --git a/Grammar/python.gram b/Grammar/python.gram
index a771abf..19d9bb3 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -627,6 +627,9 @@
| 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") }
+ | a=args for_if_clauses { _PyPegen_nonparen_genexp_in_call(p, a) }
+ | args ',' a=expression for_if_clauses {
+ RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "Generator expression must be parenthesized") }
| a=args ',' args { _PyPegen_arguments_parsing_error(p, a) }
invalid_kwarg:
| a=expression '=' {