Parse error for unicode character name literals in f-strings

[zsol]

>>> print(f"\N{greek capital letter delta}t")
Δt

but with libcst:

❯ libcst print - 
print(f"\N{greek capital letter delta}t")
Traceback (most recent call last):
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/_parser/base_parser.py", line 152, in _add_token
    plan = stack[-1].dfa.transitions[transition]
KeyError: TokenType(NAME)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/instagram/virtualenv/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/opt/instagram/virtualenv/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/tool.py", line 832, in <module>
    main(os.environ.get("LIBCST_TOOL_COMMAND_NAME", "libcst.tool"), sys.argv[1:])
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/tool.py", line 827, in main
    return lookup.get(args.action or None, _invalid_command)(proc_name, command_args)
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/tool.py", line 277, in _print_tree_impl
    else PartialParserConfig()
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/_parser/entrypoints.py", line 76, in parse_module
    detect_default_newline=True,
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/_parser/entrypoints.py", line 51, in _parse
    result = parser.parse()
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/_parser/base_parser.py", line 111, in parse
    self._add_token(token)
  File "/opt/instagram/virtualenv/lib/python3.7/site-packages/fbcode/libcst/_parser/base_parser.py", line 191, in _add_token
    raw_column=token.start_pos[1],
libcst._exceptions.ParserSyntaxError: Syntax Error @ 1:18.
Incomplete input. Encountered 'capital', but expected '!', ':', or '}'.

print(f"\N{greek capital letter delta}t")
                 ^

[zsol]

See also davidhalter/parso#154

[jimmylai]

This issues is fixed by davidhalter/parso#160 and will be available in the next release.