Avoid recursion in a specific example, see also #1458

jedi/inference/compiled/mixed.py

@@ -13,10 +13,11 @@ from jedi import settings
 from jedi.inference import compiled
 from jedi.cache import underscore_memoization
 from jedi.file_io import FileIO
-from jedi.inference.base_value import ValueSet, ValueWrapper
+from jedi.inference.base_value import ValueSet, ValueWrapper, NO_VALUES
 from jedi.inference.helpers import SimpleGetItemNotFound
 from jedi.inference.value import ModuleValue
-from jedi.inference.cache import inference_state_function_cache
+from jedi.inference.cache import inference_state_function_cache, \
+    inference_state_method_cache
 from jedi.inference.compiled.getattr_static import getattr_static
 from jedi.inference.compiled.access import compiled_objects_cache, \
     ALLOWED_GETITEM_TYPES, get_api_type
@@ -58,8 +59,13 @@ class MixedObject(ValueWrapper):
         # should be very precise, especially for stuff like `partial`.
         return self.compiled_object.get_signatures()
 
+    @inference_state_method_cache(default=NO_VALUES)
     def py__call__(self, arguments):
-        return (to_stub(self._wrapped_value) or self._wrapped_value).py__call__(arguments)
+        # Fallback to the wrapped value if to stub returns no values.
+        values = to_stub(self._wrapped_value)
+        if not values:# or self in values:
+            values = self._wrapped_value
+        return values.py__call__(arguments)
 
     def get_safe_value(self, default=_sentinel):
         if default is _sentinel:

test/test_inference/test_mixed.py

@@ -1,7 +1,42 @@
+import sys
+if sys.version_info > (3, 5):
+    from typing import Generic, TypeVar, List
+
+import pytest
+
 import jedi
 
 
+def interpreter(code, namespace, *args, **kwargs):
+    return jedi.Interpreter(code, [namespace], *args, **kwargs)
+
+
 def test_on_code():
     from functools import wraps
-    i = jedi.Interpreter("wraps.__code__", [{'wraps':wraps}])
+    i = interpreter("wraps.__code__", {'wraps': wraps})
     assert i.goto_definitions()
+
+
+@pytest.mark.skipif('sys.version_info < (3,5)')
+def test_generics():
+    # Used to raise a recursion error
+    T = TypeVar('T')
+
+    class Stack(Generic[T]):
+        def __init__(self):
+            self.items = []  # type: List[T]
+
+        def push(self, item):
+            self.items.append(item)
+
+        def pop(self):
+            # type: () -> T
+            return self.items.pop()
+
+    class StackWrapper():
+        def __init__(self):
+            self.stack = Stack()
+            self.stack.push(1)
+
+    s = StackWrapper()
+    print(interpreter('s.stack.pop().', locals()).completions())