bpo-43017: Improve error message for unparenthesised tuples in comprehensions (GH24314)
diff --git a/Grammar/python.gram b/Grammar/python.gram
index 05ddce5..e72158b 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -507,7 +507,7 @@
list[expr_ty]:
| '[' a=[star_named_expressions] ']' { _Py_List(a, Load, EXTRA) }
listcomp[expr_ty]:
- | '[' a=named_expression ~ b=for_if_clauses ']' { _Py_ListComp(a, b, EXTRA) }
+ | '[' a=named_expression b=for_if_clauses ']' { _Py_ListComp(a, b, EXTRA) }
| invalid_comprehension
tuple[expr_ty]:
| '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' {
@@ -516,11 +516,11 @@
| '(' a=(yield_expr | named_expression) ')' { a }
| invalid_group
genexp[expr_ty]:
- | '(' a=named_expression ~ b=for_if_clauses ')' { _Py_GeneratorExp(a, b, EXTRA) }
+ | '(' a=named_expression b=for_if_clauses ')' { _Py_GeneratorExp(a, b, EXTRA) }
| invalid_comprehension
set[expr_ty]: '{' a=star_named_expressions '}' { _Py_Set(a, EXTRA) }
setcomp[expr_ty]:
- | '{' a=named_expression ~ b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
+ | '{' a=named_expression b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
| invalid_comprehension
dict[expr_ty]:
| '{' a=[double_starred_kvpairs] '}' {
@@ -692,6 +692,8 @@
invalid_comprehension:
| ('[' | '(' | '{') a=starred_expression for_if_clauses {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "iterable unpacking cannot be used in comprehension") }
+ | ('[' | '{') a=star_named_expression ',' [star_named_expressions] {
+ RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "did you forget parentheses around the comprehension target?") }
invalid_dict_comprehension:
| '{' a='**' bitwise_or for_if_clauses '}' {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "dict unpacking cannot be used in dict comprehension") }