Merge pull request #635 from google/google_sync

When raising not-supported-yet for Alias = Union[T, ...] set the type…

pytype/tests/py3/test_typevar.py

@@ -415,12 +415,11 @@ def f(x: T) -> T:
 
   def test_use_unsupported_typevar(self):
     # Test that we don't crash when using this pattern (b/162274390)
-    # Note that it throws four distinct errors, which is less than ideal.
     self.CheckWithErrors("""
       from typing import List, TypeVar, Union
       T = TypeVar("T")
       Tree = Union[T, List['Tree']]  # not-supported-yet  # not-supported-yet
-      def f(x: Tree[int]): ...  # invalid-typevar  # unsupported-operands
+      def f(x: Tree[int]): ... # no error since Tree is set to Any
     """)
 
 

pytype/vm.py

@@ -1287,11 +1287,13 @@ def store_global(self, state, name, value):
     """Same as store_local except for globals."""
     return self._store_value(state, name, value, local=False)
 
-  def _check_aliased_type_params(self, value):
+  def _check_for_aliased_type_params(self, value):
     for v in value.data:
       if isinstance(v, abstract.Union) and v.formal:
         self.errorlog.not_supported_yet(
             self.frames, "aliases of Unions with type parameters")
+        return True
+    return False
 
   def _remove_recursion(self, node, name, value):
     """Remove any recursion in the named value."""
@@ -1374,7 +1376,8 @@ def _pop_and_store(self, state, op, name, local):
     value = self._apply_annotation(
         state, op, name, orig_val, annotations_dict, check_types)
     value = self._remove_recursion(state.node, name, value)
-    self._check_aliased_type_params(value)
+    if self._check_for_aliased_type_params(value):
+      value = self.new_unsolvable(state.node)
     state = state.forward_cfg_node()
     state = self._store_value(state, name, value, local)
     self.trace_opcode(op, name, value)