diff --git a/jedi/evaluate/__init__.py b/jedi/evaluate/__init__.py
index 3feb4491..365609f9 100644
--- a/jedi/evaluate/__init__.py
+++ b/jedi/evaluate/__init__.py
@@ -109,7 +109,7 @@ class Evaluator(object):
             return f.filter_name(scopes)
         return f.find(scopes, resolve_decorator)
 
-    @memoize_default(default=(), evaluator_is_first_arg=True)
+    @memoize_default(default=[], evaluator_is_first_arg=True)
     @recursion.recursion_decorator
     @debug.increase_indent
     def eval_statement(self, stmt, seek_name=None):
diff --git a/jedi/evaluate/finder.py b/jedi/evaluate/finder.py
index f9e4e6bf..0638aa28 100644
--- a/jedi/evaluate/finder.py
+++ b/jedi/evaluate/finder.py
@@ -11,7 +11,6 @@ would check whether a flow has the form of ``if isinstance(a, type_or_tuple)``.
 Unfortunately every other thing is being ignored (e.g. a == '' would be easy to
 check for -> a is a string). There's big potential in these checks.
 """
-import copy
 import sys
 
 from jedi._compatibility import hasattr, unicode, u, reraise
diff --git a/jedi/evaluate/representation.py b/jedi/evaluate/representation.py
index 93445e76..070e502f 100644
--- a/jedi/evaluate/representation.py
+++ b/jedi/evaluate/representation.py
@@ -169,6 +169,12 @@ class Instance(use_metaclass(CachedMetaClass, Executable)):
             return False
 
     def get_index_types(self, indexes=[]):
+        if any([isinstance(i, iterable.Slice) for i in indexes]):
+            # Slice support in Jedi is very marginal, at the moment, so just
+            # ignore them in case of __getitem__.
+            # TODO support slices in a more general way.
+            indexes = []
+
         try:
             return self.execute_subscope_by_name('__getitem__', indexes)
         except KeyError:
diff --git a/test/completion/arrays.py b/test/completion/arrays.py
index ea3cbcf8..1d4d0e1d 100644
--- a/test/completion/arrays.py
+++ b/test/completion/arrays.py
@@ -30,6 +30,9 @@ b = [6,7]
 #? int()
 b[8-7]
 
+# -----------------
+# Slices
+# -----------------
 #? list()
 b[8:]
 
@@ -37,6 +40,14 @@ b[8:]
 b[int():]
 
 
+class _StrangeSlice():
+    def __getitem__(self, slice):
+        return slice
+
+#? []
+_StrangeSlice()[1:2]
+
+
 # -----------------
 # iterable multiplication
 # -----------------