Pylint incorrectly flags as unused-import things that are used in type comments

[chadrik]

This issue was supposed to have been fixed in #1063, but it appears that it was not completely fixed.

Current Behavior

The following example works correctly, and all imports from the typing module are correctly identified as being "used":

"""docstring"""

from typing import Iterable, List, Sequence

def function(arg1, arg2):
    # type: (Iterable, List) -> Sequence
    """docstring"""
    print(arg1, arg2)

$ pylint ./pylint_test2.py 

------------------------------------
Your code has been rated at 10.00/10

But use of the one-arg-per-line form of pep 484 is not properly detected by pylint:

"""docstring"""

from typing import Iterable, List, Sequence

def function(arg1,  # type: Iterable
             arg2  # type: List
            ):
    # type: (...) -> Sequence
    """docstring"""
    print(arg1, arg2)

$ pylint ./pylint_test1.py 
************* Module pylint_test1
pylint_test1.py:3:0: W0611: Unused Iterable imported from typing (unused-import)
pylint_test1.py:3:0: W0611: Unused List imported from typing (unused-import)

-------------------------------------------------------------------
Your code has been rated at 3.33/10 (previous run: -3.33/10, +6.67

Expected Behavior

There should be no error: all items should be detected as being used, as in the first example

Environment

$ pylint --version
pylint 2.3.1
astroid 2.2.5
Python 3.7.3 (default, Jun 19 2019, 07:40:15) 
[Clang 10.0.0 (clang-1000.11.45.5)]

I also tried with python 3.6.1. Same issue.

[chadrik]

Wow. Thanks for fixing that so fast!

[davidgiga1993]

I'm still having the same issue with python 3.7.4 on linux:

from typing import Optional

class A:
    def __init__(self):
        self.field = None  # type: Optional[str]

pylint  Test.py
************* Module Test
...
Test.py:1:0: W0611: Unused Optional imported from typing (unused-import)

pylint --version
pylint 2.4.2
astroid 2.3.1
Python 3.7.4 (default, Jul 23 2019, 10:08:33)
[GCC 4.8.5]

Interestingly I don't get this issue on windows with python 3.7.3:

pylint --version
pylint 2.4.2
astroid 2.3.1
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 21:26:53) [MSC v.1916 32 bit (Intel)]

Any ideas what could cause this issue?

[gaborbernat]

"""yes"""
from datetime import datetime
from typing import Optional, Any


def magic(alpha, beta, gamma):
    # type: (str, Optional[str], Optional[datetime]) -> Any
    """going strong"""
    return alpha, beta, gamma

************* Module test
test.py:2:0: W0611: Unused datetime imported from datetime (unused-import)

------------------------------------------------------------------
Your code has been rated at 7.50/10 (previous run: 7.50/10, +0.00)

pylint --version                                                                                                                                               790ms  Thu 31 Oct 10:20:47 2019
pylint 2.4.3
astroid 2.3.2
Python 3.8.0 (default, Oct 15 2019, 18:49:26)
[Clang 11.0.0 (clang-1100.0.33.8)]

See the above also throws this.

[PCManticore]

@davidgiga1993 The fix was released as part of 2.4.3, it seems you are using 2.4.2. Can you also give it a try with 2.4.3 and see if it works for you?

@gaborbernat Thanks, I can reproduce that one using the latest version.

[PCManticore]

Thanks for that additional example @gaborbernat This is now fixed in master and the 2.4 branch, will be released as 2.4.4 soon.