Fix SyntaxError messages for invalid assignment targets #127
Conversation
| | '(' a=star_target ')' { _PyPegen_set_expr_context(p, a, Store) } | ||
| | '(' a=[star_targets_seq] ')' { _Py_Tuple(a, Store, EXTRA) } | ||
| | '[' a=[star_targets_seq] ']' { _Py_List(a, Store, EXTRA) } | ||
| star_target_end: ')' | ']' | ',' | '=' | 'in' |
There was a problem hiding this comment.
I presume in is here because of for <target> in <expr>, but this would mean that you'd get a different error for
a in b = 42
than you'd get for
a < b = 42
There was a problem hiding this comment.
Actually not, because when parsing the invalid target the whole expression gets parsed, which means that cannot assign to comparison is displayed for both.
You're right. What I said above was me talking about 1 in a = 42 for some reason, which would actually display the correct error message, since 1 is not a valid assignment target.
Another problem with this is that it isn't really usable in for-statements, because the in always gets parsed as the comparison operator in, which means that even something like for f() in a: pass displays the cannot assign to comparison error.
|
Yeah, this is really awful. Not sure what to do yet. |
|
I guess this can be closed, since python#20076 is now merged. |
Just wanted to show you what it takes to provide correct error messages for invalid targets without generating too much noise on the upstream repo or the bpo issue.
IMHO this is very ugly, but it might be the only way to do it, until we've found a better solution and since we did a similar thing for
del_targets.Thoughts?