Mypy plugin for typed decorators

[sobolevn]

from returns.result import safe

@safe
def test() -> int:
    return 1

reveal_type(test)
reveal_type(test())

When running mypy it yields correct results:

» mypy test.py --show-traceback
test.py:7: error: Revealed type is 'def () -> returns.result.Result[builtins.int*, builtins.Exception]'
test.py:8: error: Revealed type is 'returns.result.Result[builtins.int*, builtins.Exception]'

I have not tested it yet, I will need to implement #47 first, but this is huge!
Since I am really annoyed by this issue. I had so many mistakes already in my project because of this limitation.

[proofit404]

I suggest to move it into returns.contrib.mypy.decorator_plugin.

This is a universal approach other projects has in their naming schema.

[proofit404]

I strongly suggest using https://github.com/mkurnikov/pytest-mypy-plugins before the merge.

[sobolevn]

@proofit404

I suggest to move it into returns.contrib.mypy.decorator_plugin.

Good idea!

I strongly suggest using https://github.com/mkurnikov/pytest-mypy-plugins before the merge.

Sure! That's what I have mentioned in the PR's body:

I have not tested it yet, I will need to implement #47 first, but this is huge!