Ignore typing errors in individual blocks

It is already possible to silence errors using # type: ignore on individual lines, and - since #626) also for a whole file.

Additionally it would be nice to ignore errors on individual blocks. Especially on a class/function level when abstracting away an untyped library. For example:

class MyAbstraction:

    def __init__(self, url: str) -> None:
        self.hostname = url.host  # <-- I want this to be caught by the type-checker

    def some_call(self) -> int:
        # type: ignore
        result = api.untyped_call()
        return result

    def another_large_call(self) -> int:
        # type: ignore
        result_1 = api.untyped_call_1()
        result_2 = api.untyped_call_2()
        result = result_1 + result_2
        return result

When running mypy in "strict" mode the code will be littered with messages like Call to an untyped function ... in a typed context. Currently the only options are:

• Add # type: ignore on each line causing errors by the external library
  • Disadvantage: Cumbersome (many type-comments needed)
  • Advantage: Only the problematic calls are silenced
• Add # type: ignore to the file
  • Disadvantage: Typing errors unrelated to the external library become invisible
  • Advantage: Only one line to add

The second option is best used if a module contains only calls to the external library. For new projects this is doable, but older/larger code-bases often need some refactoring for this. And this can be error-prone and seems risky to do only for type-hinting.

Having the option to disable errors on either a class-level or block-level would add a lot of flexibility.

issue にはファイル、テスト、エントリポイントが記載されていません。まず、strict mode で mypy が # type: ignore をどのように処理するかを追跡し、次にクラスレベルおよびブロックレベルの抑制の範囲と動作を定義してください。要求されたエラーを、関係のない型チェックエラーを隠すことなく選択的に抑制できれば完了です。