diff --git a/jedi/api/__init__.py b/jedi/api/__init__.py
index da91b531..c35323ac 100644
--- a/jedi/api/__init__.py
+++ b/jedi/api/__init__.py
@@ -491,7 +491,7 @@ class Script(object):
             origins = cache.cache_call_signatures(_callable, user_stmt)
         debug.speed('func_call followed')
 
-        return [classes.CallDef(o, index, call) for o in origins
+        return [classes.CallDef(self._evaluator, o, index, call) for o in origins
                 if o.isinstance(er.Function, er.Instance, er.Class)
                 or isinstance(o, compiled.CompiledObject) and o.type() != 'module']
 
diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 96f61ba3..a65fa6d6 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -548,7 +548,8 @@ class CallDef(object):
     It knows what functions you are currently in. e.g. `isinstance(` would
     return the `isinstance` function. without `(` it would return nothing.
     """
-    def __init__(self, executable, index, call):
+    def __init__(self, evaluator, executable, index, call):
+        self._evaluator = evaluator
         self._executable = executable
         self.index = index
         self._call = call
@@ -558,7 +559,8 @@ class CallDef(object):
         if self._executable.isinstance(er.Function):
             if isinstance(self._executable, er.InstanceElement):
                 params = self._executable.params[1:]
-            return self._executable.params
+            else:
+                params = self._executable.params
         elif self._executable.isinstance(er.compiled.CompiledObject):
             params = self._executable.params
         else:
@@ -567,7 +569,7 @@ class CallDef(object):
                 params = sub.params[1:]  # ignore self
             except KeyError:
                 return []
-        return [Param(p) for p in params]
+        return [Param(self._evaluator, p) for p in params]
 
     @property
     def bracket_start(self):