I am strongly in favor of diverging type annotation syntax from Python syntax. Currently, type annotations are a very useful tool, but often clunky to use. Enhancements have been made, but design space is limited when working within existing Python syntax. Type annotations have a different set of rules, needs, and constraints than general-purpose Python code. This is similar to other domain specific languages like regular expressions. Ideally, Python itself would not check the syntax of annotations, except as needed for determining the end of an annotation.