Crash Building error when trying to create ast representation of module 'test'

[lucas-str]

Bug description

With astroid 2.12.7, when parsing the following file:

from dataclasses import dataclass, InitVar


@dataclass
class TestClass:
    """Test Class"""

    config: InitVar = None

pylint crashed with a AstroidBuildingError and with the following stacktrace:

Traceback (most recent call last):
  File "/tmp/test/env/lib/python3.9/site-packages/pylint/lint/pylinter.py", line 991, in get_ast
    return MANAGER.ast_from_file(filepath, modname, source=True)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/manager.py", line 117, in ast_from_file
    return AstroidBuilder(self).file_build(filepath, modname)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/builder.py", line 135, in file_build
    return self._post_build(module, builder, encoding)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/builder.py", line 161, in _post_build
    module = self._manager.visit_transforms(module)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/manager.py", line 94, in visit_transforms
    return self._transform.visit(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 89, in visit
    return self._visit(module)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 54, in _visit
    visited = self._visit_generic(value)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 61, in _visit_generic
    return [self._visit_generic(child) for child in node]
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 61, in <listcomp>
    return [self._visit_generic(child) for child in node]
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 67, in _visit_generic
    return self._visit(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 57, in _visit
    return self._transform(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 39, in _transform
    ret = transform_func(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/brain/brain_dataclasses.py", line 97, in dataclass_transform
    init_str = _generate_dataclass_init(
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/brain/brain_dataclasses.py", line 209, in _generate_dataclass_init
    param_str = f"{name}: {annotation.as_string()}"
AttributeError: 'NoneType' object has no attribute 'as_string'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/tmp/test/env/lib/python3.9/site-packages/pylint/lint/pylinter.py", line 690, in _get_asts
    ast_per_fileitem[fileitem] = self.get_ast(
  File "/tmp/test/env/lib/python3.9/site-packages/pylint/lint/pylinter.py", line 1010, in get_ast
    raise astroid.AstroidBuildingError(
astroid.exceptions.AstroidBuildingError: Building error when trying to create ast representation of module 'test'

Configuration

No response

Command used

pylint test.py

Pylint output

Traceback (most recent call last):
  File "/tmp/test/env/lib/python3.9/site-packages/pylint/lint/pylinter.py", line 991, in get_ast
    return MANAGER.ast_from_file(filepath, modname, source=True)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/manager.py", line 117, in ast_from_file
    return AstroidBuilder(self).file_build(filepath, modname)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/builder.py", line 135, in file_build
    return self._post_build(module, builder, encoding)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/builder.py", line 161, in _post_build
    module = self._manager.visit_transforms(module)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/manager.py", line 94, in visit_transforms
    return self._transform.visit(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 89, in visit
    return self._visit(module)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 54, in _visit
    visited = self._visit_generic(value)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 61, in _visit_generic
    return [self._visit_generic(child) for child in node]
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 61, in <listcomp>
    return [self._visit_generic(child) for child in node]
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 67, in _visit_generic
    return self._visit(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 57, in _visit
    return self._transform(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/transforms.py", line 39, in _transform
    ret = transform_func(node)
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/brain/brain_dataclasses.py", line 97, in dataclass_transform
    init_str = _generate_dataclass_init(
  File "/tmp/test/env/lib/python3.9/site-packages/astroid/brain/brain_dataclasses.py", line 209, in _generate_dataclass_init
    param_str = f"{name}: {annotation.as_string()}"
AttributeError: 'NoneType' object has no attribute 'as_string'
************* Module test
test.py:1:0: F0002: test.py: Fatal error while checking 'test.py'. Please open an issue in our bug tracker so we address this. There is a pre-filled template that you can use in '.cache/pylint/pylint-crash-2022-09-06-14-25-21.txt'. (astroid-error)

Expected behavior

No crash.

Pylint version

pylint 2.15.0
astroid 2.12.7
Python 3.9.2 (default, Feb 28 2021, 17:03:44)
[GCC 10.2.1 20210110]

OS / Environment

Debian 11.4

Additional dependencies

No response

[DanielNoord]

😡

Sorry @Pierre-Sassoulas, that seemed like a straight forward PR.

PR incoming!