isinstance() tuple unpacking raises mypy internal error

[trevorbaca]

The tuple unpacking here ...

two_types = (list, tuple)                                                       
third_type = str                                                                
if isinstance('text', (*two_types, third_type)):                                
    print('hello')                                                              

... produces ...

mypy --show-traceback test.py
test.py:3: error: INTERNAL ERROR -- please report a bug at https://github.com/python/mypy/issues version: 0.560
Traceback (most recent call last):
  File "/Users/trevorbaca/.virtualenvs/abjad3/bin/mypy", line 11, in <module>
    sys.exit(console_entry())
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/__main__.py", line 7, in console_entry
    main(None)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/main.py", line 66, in main
    res = type_check_only(sources, bin_dir, options)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/main.py", line 119, in type_check_only
    options=options)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/build.py", line 218, in build
    graph = dispatch(sources, manager)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/build.py", line 1997, in dispatch
    process_graph(graph, manager)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/build.py", line 2299, in process_graph
    process_stale_scc(graph, scc, manager)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/build.py", line 2475, in process_stale_scc
    graph[id].type_check_first_pass()
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/build.py", line 1876, in type_check_first_pass
    self.type_checker().check_first_pass()
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checker.py", line 196, in check_first_pass
    self.accept(d)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checker.py", line 286, in accept
    stmt.accept(self)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/nodes.py", line 921, in accept
    return visitor.visit_if_stmt(self)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checker.py", line 2181, in visit_if_stmt
    t = self.expr_checker.accept(e)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checkexpr.py", line 2365, in accept
    typ = node.accept(self)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/nodes.py", line 1245, in accept
    return visitor.visit_call_expr(self)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checkexpr.py", line 271, in visit_call_expr
    self.check_runtime_protocol_test(e)
  File "/Users/trevorbaca/.virtualenvs/abjad3/lib/python3.6/site-packages/mypy/checkexpr.py", line 283, in check_runtime_protocol_test
    tp = self.chk.type_map[expr]
KeyError: <mypy.nodes.StarExpr object at 0x10cb639b0>
test.py:3: : note: use --pdb to drop into pdb

... when run by mypy.

[gvanrossum]

Confirmed on master and in release-0.600.

[ilevkivskyi]

(This looks like an old bug so setting priority to normal.)