AssertionError: Var is lacking info - access to class variable imported in context class

[ampanasiuk]

Crash Report

# user.py
name = 'Bob'

# hello.py
class Hello:
    from user import name

    def greet(self) -> None:
          print(self.name)

Traceback

mypy/nodes.py:2705 (__getattribute__) is the deepest frame

To Reproduce

$ mypy hello.py

Your Environment

• Mypy version used: 0.910
• Mypy command-line flags: filename
• Mypy configuration options from mypy.ini (and other config files): no
• Python version used: 3.8.12
• Operating system and version: cygwin

Thanks for looking into this,

[ampanasiuk]

For anyone inconvenienced with this issue, this is how to work around it:

# user.py
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    class name:
        pass
else:
    name = 'Bob'

[hauntsaninja]

Thanks, similar to #7806

Reproes on master, full traceback:

version: 0.920+dev.4f59ca490072a45dce5839e6397791d79dcf3352
Traceback (most recent call last):
  File "/Users/shantanu/.virtualenvs/mypy-fpoc/bin/mypy", line 33, in <module>
    sys.exit(load_entry_point('mypy', 'console_scripts', 'mypy')())
  File "/Users/shantanu/dev/mypy/mypy/__main__.py", line 12, in console_entry
    main(None, sys.stdout, sys.stderr)
  File "/Users/shantanu/dev/mypy/mypy/main.py", line 96, in main
    res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
  File "/Users/shantanu/dev/mypy/mypy/main.py", line 173, in run_build
    res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 180, in build
    result = _build(
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 256, in _build
    graph = dispatch(sources, manager, stdout)
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 2715, in dispatch
    process_graph(graph, manager)
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 3046, in process_graph
    process_stale_scc(graph, scc, manager)
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 3144, in process_stale_scc
    graph[id].type_check_first_pass()
  File "/Users/shantanu/dev/mypy/mypy/build.py", line 2180, in type_check_first_pass
    self.type_checker().check_first_pass()
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 317, in check_first_pass
    self.accept(d)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 423, in accept
    stmt.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 1000, in accept
    return visitor.visit_class_def(self)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 1778, in visit_class_def
    self.accept(defn.defs)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 423, in accept
    stmt.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 1069, in accept
    return visitor.visit_block(self)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 2040, in visit_block
    self.accept(s)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 423, in accept
    stmt.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 727, in accept
    return visitor.visit_func_def(self)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 763, in visit_func_def
    self._visit_func_def(defn)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 767, in _visit_func_def
    self.check_func_item(defn, name=defn.name)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 829, in check_func_item
    self.check_func_def(defn, typ, name)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 1014, in check_func_def
    self.accept(item.body)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 423, in accept
    stmt.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 1069, in accept
    return visitor.visit_block(self)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 2040, in visit_block
    self.accept(s)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 423, in accept
    stmt.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 1087, in accept
    return visitor.visit_expression_stmt(self)
  File "/Users/shantanu/dev/mypy/mypy/checker.py", line 3316, in visit_expression_stmt
    self.expr_checker.accept(s.expr, allow_none_return=True, always_allow_any=True)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 3966, in accept
    typ = self.visit_call_expr(node, allow_none_return=True)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 288, in visit_call_expr
    return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 377, in visit_call_expr_inner
    ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 884, in check_call_expr_with_callee_type
    return self.check_call(callee_type, e.args, e.arg_kinds, e,
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 948, in check_call
    return self.check_overload_call(callee, args, arg_kinds, arg_names, callable_name,
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 1589, in check_overload_call
    arg_types = self.infer_arg_types_in_empty_context(args)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 1132, in infer_arg_types_in_empty_context
    arg_type = self.accept(arg)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 3972, in accept
    typ = node.accept(self)
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 1631, in accept
    return visitor.visit_member_expr(self)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 2086, in visit_member_expr
    result = self.analyze_ordinary_member_access(e, is_lvalue)
  File "/Users/shantanu/dev/mypy/mypy/checkexpr.py", line 2104, in analyze_ordinary_member_access
    member_type = analyze_member_access(
  File "/Users/shantanu/dev/mypy/mypy/checkmember.py", line 126, in analyze_member_access
    result = _analyze_member_access(name, typ, mx, override_info)
  File "/Users/shantanu/dev/mypy/mypy/checkmember.py", line 143, in _analyze_member_access
    return analyze_instance_member_access(name, typ, mx, override_info)
  File "/Users/shantanu/dev/mypy/mypy/checkmember.py", line 227, in analyze_instance_member_access
    return analyze_member_var_access(name, typ, info, mx)
  File "/Users/shantanu/dev/mypy/mypy/checkmember.py", line 382, in analyze_member_var_access
    return analyze_var(name, v, itype, info, mx, implicit=implicit)
  File "/Users/shantanu/dev/mypy/mypy/checkmember.py", line 555, in analyze_var
    itype = map_instance_to_supertype(itype, var.info)
  File "/Users/shantanu/dev/mypy/mypy/maptype.py", line 20, in map_instance_to_supertype
    if not superclass.type_vars:
  File "/Users/shantanu/dev/mypy/mypy/nodes.py", line 2876, in __getattribute__
    raise AssertionError(object.__getattribute__(self, 'msg'))
AssertionError: Var is lacking info

[sobolevn]

This might be fixed by: #11344