Huh? I remember learning the rule that you can't nest quotes inside fstrings if they are the same kind (unlike in bash) - e.g

  f"{mydict["foo"]}"

  f"{mydict['foo']}"

  f'{mydict["foo"]}'

The reason being the same like for the rstring weirdness: The lexer comes first and identifies the string literal, then for fstrings, the python parser is invoked again for each {...} expression to parse it.

This is unlike other nested expressions, which are already split up by the lexer and then parsed in one go.

Did that change at some point?

I feel like 90% of new Python features in the last 10 years just increased language complexity without any benefit.