Mypy is the standard, but too slow to integrate into editors (more appropriate for CI). PyCharm built its own implementation for this reason, but of course it's proprietary. Pyre's trying to get typecheck integration into other editors.
Why do you think it's too slow? I have it integrated with Emacs' flymake and it works pretty well. It takes less than a second to run mypy and display its results (with red underline or whatever else you have configured). From my experience, Visual Studio with F# takes similar time to type-check and show errors.
Well, I am start to writing some Typescript with tslint configured on save, and it takes way more than 1 second for a small toy project.
Even just building this project with Typescript compiler takes more than 1 second. And I don't think it is that bad because at least the process is async.
Interesting. I write TypeScript in PyCharm and I get feedback as soon as I write (PyCharm performs save automatically). I don't know how they implemented it that it's so fast.
Well, PyCharm is already doing a lot of parsing for syntax highlighting and autocompletion and other goodies. They're checker implementation probably just takes the AST PyCharm already has available to it, which saves the round-trip of saving to a file and having an outside checker open and re-parse the file.
Ok, I don't know myself, because I stopped looking for the next editor years ago, so I'd like to ask: do you know how long it takes, on average, for IDEs and editors to highlight a type error?
