fix problems with class method decorators

jedi/evaluate_representation.py

@@ -328,13 +328,13 @@ class Function(use_metaclass(cache.CachedMetaClass, pr.IsScope)):
                     debug.warning('decorator not found: %s on %s' %
                                  (dec, self.base_func))
                     return None
-                if len(dec_results) > 1:
+                decorator = dec_results.pop()
+                if dec_results:
                     debug.warning('multiple decorators found', self.base_func,
                                   dec_results)
-                decorator = dec_results.pop()
                 # Create param array.
                 old_func = Function(f, is_decorated=True)
-                if instance is not None:
+                if instance is not None and decorator.isinstance(Function):
                     old_func = InstanceElement(instance, old_func)
                     instance = None
 

test/completion/decorators.py

@@ -99,9 +99,12 @@ def nothing(a,b,c):
     return a,b,c
 
 class MethodDecoratorAsClass():
-    class_var
+    class_var = 3
+    @Decorator
     def func_without_self(arg):
         return arg
+
+    @Decorator
     def func_with_self(self, arg):
         return self.class_var