Per discussion during the typing summit at PyCon, it would be a good idea to allow extra information to be included in `# type: ignore` comments, in order to allow behavior such as suppressing individual errors (for example, with syntax like `# type: ignore[E1000]`, to suppress error 1000).

My proposal, then, is to generalize the definition of type: ignore comments to be `# type: ignore followed by a non-alphanumeric character. Then `# type: ignore[E1000]` and `# type: ignore E1000` would be valid type ignore comments while `# type: ignoreE1000` would not be.

Now that ast.parse can parse type_comments, this needs to make it into 3.8, basically, if we want to do this and be able to use the ast type_comment feature.

Ideally, the text of the type ignore would be actually included in the produced AST. As a bare minimum first step, we need to recognize type ignores with extra information and report them (and, critically, not detect them as regular type comments and produce errors when they appear in unexpected places).

I'll put up a PR to do the second part shortly.

I like the idea of separate smaller PRs, the first one looks good.

New changeset d8320ecb86da8df7c13d8bf8582507f736aa2924 by Ivan Levkivskyi (Michael J. Sullivan) in branch 'master':
bpo-36878: Allow extra text after `# type: ignore` comments (GH-13238)
https://github.com/python/cpython/commit/d8320ecb86da8df7c13d8bf8582507f736aa2924

How many more PRs do you plan? Or is this it?

New changeset 933e1509ec6efa8e6ab8c8c7ce02059ce2b6d9b9 by Ivan Levkivskyi (Michael J. Sullivan) in branch 'master':
bpo-36878: Track extra text added to 'type: ignore' in the AST (GH-13479)
https://github.com/python/cpython/commit/933e1509ec6efa8e6ab8c8c7ce02059ce2b6d9b9

I think there will be one more PR to disallow non-ASCII characters immediately after a `# type: ignore`, but otherwise I think this is done

New changeset d8a82e2897b735e2b7e9e086f1d709365a2ad72c by Miss Islington (bot) (Michael J. Sullivan) in branch 'master':
bpo-36878: Only allow text after `# type: ignore` if first character ASCII (GH-13504)
https://github.com/python/cpython/commit/d8a82e2897b735e2b7e9e086f1d709365a2ad72c

Thanks!

I think this is done!