I don't know if such tools exist already, but it's conceptually similar to a linter, so perhaps you'll find something like this by investigating linters for lan

I don't know if such tools exist already, but it's conceptually similar to a linter, so perhaps you'll find something like this by investigating linters for languages with optional type annotations (such as Python). EDIT: Found one for you: http://mypy-lang.org/ http://mypy-lang.org/