PEP 498:
"""
Because expressions may begin with a left brace ('{'), there is a problem when parsing such expressions. For example:
>>> f'{{k:v for k, v in [(1, 2), (3, 4)]}}'
'{k:v for k, v in [(1, 2), (3, 4)]}'
"""
For me, this example is crazy. You should not add a special case (ignore spaces) just to support a corner case.
This example can easily be rewritten using a temporary variable and it makes the code simpler.
items={k:v for k, v in [(1, 2), (3, 4)]; f'{items}'
Seriously, a dict-comprehension inside a f-string should be considered as an abuse of the feature. Don't you think so?
Victor