bpo-43914: Correctly highlight SyntaxError exceptions for invalid generator expression in function calls (GH-28576)

3 files changed, 18 insertions, 6 deletions

diff --git a/Parser/parser.c b/Parser/parser.c
index 3cea370..beb2176 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -17880,15 +17880,15 @@ invalid_arguments_rule(Parser *p)
         }
         D(fprintf(stderr, "%*c> invalid_arguments[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "args for_if_clauses"));
         expr_ty a;
-        asdl_comprehension_seq* for_if_clauses_var;
+        asdl_comprehension_seq* b;
         if (
             (a = args_rule(p))  // args
             &&
-            (for_if_clauses_var = for_if_clauses_rule(p))  // for_if_clauses
+            (b = for_if_clauses_rule(p))  // for_if_clauses
         )
         {
             D(fprintf(stderr, "%*c+ invalid_arguments[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "args for_if_clauses"));
-            _res = _PyPegen_nonparen_genexp_in_call ( p , a );
+            _res = _PyPegen_nonparen_genexp_in_call ( p , a , b );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 D(p->level--);
diff --git a/Parser/pegen.c b/Parser/pegen.c
index c77c534..7e2d37c 100644
--- a/Parser/pegen.c
+++ b/Parser/pegen.c
@@ -2551,8 +2551,17 @@ void *_PyPegen_arguments_parsing_error(Parser *p, expr_ty e) {
     return RAISE_SYNTAX_ERROR(msg);
 }
 
+
+static inline expr_ty
+_PyPegen_get_last_comprehension_item(comprehension_ty comprehension) {
+    if (comprehension->ifs == NULL || asdl_seq_LEN(comprehension->ifs) == 0) {
+        return comprehension->iter;
+    }
+    return PyPegen_last_item(comprehension->ifs, expr_ty);
+}
+
 void *
-_PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args)
+_PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args, asdl_comprehension_seq *comprehensions)
 {
     /* The rule that calls this function is 'args for_if_clauses'.
        For the input f(L, x for x in y), L and x are in args and
@@ -2566,8 +2575,11 @@ _PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args)
         return NULL;
     }
 
-    return RAISE_SYNTAX_ERROR_STARTING_FROM(
+    comprehension_ty last_comprehension = PyPegen_last_item(comprehensions, comprehension_ty);
+
+    return RAISE_SYNTAX_ERROR_KNOWN_RANGE(
         (expr_ty) asdl_seq_GET(args->v.Call.args, len - 1),
+        _PyPegen_get_last_comprehension_item(last_comprehension),
         "Generator expression must be parenthesized"
     );
 }
diff --git a/Parser/pegen.h b/Parser/pegen.h
index 57d1177..8721d7e 100644
--- a/Parser/pegen.h
+++ b/Parser/pegen.h
@@ -327,7 +327,7 @@ _RAISE_SYNTAX_ERROR_INVALID_TARGET(Parser *p, TARGETS_TYPE type, void *e)
 }
 
 void *_PyPegen_arguments_parsing_error(Parser *, expr_ty);
-void *_PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args);
+void *_PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args, asdl_comprehension_seq *comprehensions);
 
 
 // Generated function in parse.c - function definition in python.gram