I'm in favour of the approach proposed in PEP 649.Movie trailer: "In a world where annotations are arbitrary non-Python syntax..."It seems to me we could always have annotations evaluate to Python expressions *and* support any arbitrary syntax (e.g. through Annotated[...] or similar mechanism). What would a relaxed inline syntax provide that a well-placed Annotated[type, ArbitraryNonPythonSyntax("...")] annotation wouldn't? .