Add syntax error for empty type parameter list (#12030)

## Summary

(I'm pretty sure I added this in the parser re-write but must've got
lost in the rebase?)

This PR raises a syntax error if the type parameter list is empty.

As per the grammar, there should be at least one type parameter:
```
type_params: 
    | invalid_type_params
    | '[' type_param_seq ']' 

type_param_seq: ','.type_param+ [','] 
```

Verified via the builtin `ast` module as well:
```console    
$ python3.13 -m ast parser/_.py
Traceback (most recent call last):
  [..]
  File "parser/_.py", line 1
    def foo[]():
            ^
SyntaxError: Type parameter list cannot be empty
```

## Test Plan

Add inline test cases and update the snapshots.
This commit is contained in:
Dhruv Manilawala 2024-06-26 08:10:35 +05:30 committed by GitHub
parent 83fe44728b
commit 7cb2619ef5
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
4 changed files with 116 additions and 0 deletions

View file

@ -0,0 +1,3 @@
def foo[]():
pass
type ListOrSet[] = list | set