kwargs expension with Mapping raise AttributeError: 'NoneType' object has no attribute 'get_line'

[tharvik]

from typing import Mapping

a = {}  # type: Mapping
dict(**a)

raise

Traceback (most recent call last):
  File "/usr/lib/python-exec/python3.4/mypy", line 6, in <module>
    main(__file__)
  File "/usr/lib64/python3.4/site-packages/mypy/main.py", line 54, in main
    res = type_check_only(sources, bin_dir, options)
  File "/usr/lib64/python3.4/site-packages/mypy/main.py", line 102, in type_check_only
    python_path=options.python_path)
  File "/usr/lib64/python3.4/site-packages/mypy/build.py", line 209, in build
    dispatch(sources, manager)
  File "/usr/lib64/python3.4/site-packages/mypy/build.py", line 1325, in dispatch
    process_graph(graph, manager)
  File "/usr/lib64/python3.4/site-packages/mypy/build.py", line 1456, in process_graph
    process_stale_scc(graph, scc)
  File "/usr/lib64/python3.4/site-packages/mypy/build.py", line 1486, in process_stale_scc
    graph[id].type_check()
  File "/usr/lib64/python3.4/site-packages/mypy/build.py", line 1305, in type_check
    manager.type_checker.visit_file(self.tree, self.xpath)
  File "/usr/lib64/python3.4/site-packages/mypy/checker.py", line 424, in visit_file
    self.accept(d)
  File "/usr/lib64/python3.4/site-packages/mypy/checker.py", line 465, in accept
    typ = node.accept(self)
  File "/usr/lib64/python3.4/site-packages/mypy/nodes.py", line 729, in accept
    return visitor.visit_expression_stmt(self)
  File "/usr/lib64/python3.4/site-packages/mypy/checker.py", line 1570, in visit_expression_stmt
    self.accept(s.expr)
  File "/usr/lib64/python3.4/site-packages/mypy/checker.py", line 465, in accept
    typ = node.accept(self)
  File "/usr/lib64/python3.4/site-packages/mypy/nodes.py", line 1185, in accept
    return visitor.visit_call_expr(self)
  File "/usr/lib64/python3.4/site-packages/mypy/checker.py", line 1997, in visit_call_expr
    return self.expr_checker.visit_call_expr(e)
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 141, in visit_call_expr
    return self.check_call_expr_with_callee_type(callee_type, e)
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 192, in check_call_expr_with_callee_type
    e.arg_names, callable_node=e.callee)[0]
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 257, in check_call
    messages=arg_messages)
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 666, in overload_call_target
    typ)
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 742, in erased_signature_similarity
    None, check_arg=check_arg)
  File "/usr/lib64/python3.4/site-packages/mypy/checkexpr.py", line 614, in check_argument_types
    messages.invalid_keyword_var_arg(arg_type, context)
  File "/usr/lib64/python3.4/site-packages/mypy/messages.py", line 687, in invalid_keyword_var_arg
    context)
  File "/usr/lib64/python3.4/site-packages/mypy/messages.py", line 147, in fail
    self.report(msg, context, 'error', file=file)
  File "/usr/lib64/python3.4/site-packages/mypy/messages.py", line 143, in report
    self.errors.report(context.get_line(), msg.strip(), severity=severity, file=file)
AttributeError: 'NoneType' object has no attribute 'get_line'

but using

from typing import Dict

a = {}  # type: Dict
dict(**a)

does nothing, it seems to be specific to Mapping or MutableMapping.