diff --git a/jedi/evaluate/dynamic.py b/jedi/evaluate/dynamic.py
index cf6f19e3..4d57c0b9 100644
--- a/jedi/evaluate/dynamic.py
+++ b/jedi/evaluate/dynamic.py
@@ -86,7 +86,7 @@ def search_params(evaluator, execution_context, funcdef):
             params = [MergedExecutedParams(executed_params) for executed_params in zipped_params]
             # Evaluate the ExecutedParams to types.
         else:
-            params = [create_default_param(execution_context, p) for p in funcdef.params]
+            params = [create_default_param(execution_context, p) for p in funcdef.get_params()]
         debug.dbg('Dynamic param result finished', color='MAGENTA')
         return params
     finally:
diff --git a/jedi/evaluate/param.py b/jedi/evaluate/param.py
index c8b3b0ab..57f35138 100644
--- a/jedi/evaluate/param.py
+++ b/jedi/evaluate/param.py
@@ -236,7 +236,7 @@ def get_params(execution_context, var_args):
     funcdef = execution_context.tree_node
     parent_context = execution_context.parent_context
 
-    for param in funcdef.params:
+    for param in funcdef.get_params():
         param_dict[param.name.value] = param
     unpacked_va = list(var_args.unpack(funcdef))
     var_arg_iterator = common.PushBackIterator(iter(unpacked_va))
@@ -245,7 +245,7 @@ def get_params(execution_context, var_args):
     keys_used = {}
     keys_only = False
     had_multiple_value_error = False
-    for param in funcdef.params:
+    for param in funcdef.get_params():
         # The value and key can both be null. There, the defaults apply.
         # args / kwargs will just be empty arrays / dicts, respectively.
         # Wrong value count is just ignored. If you try to test cases that are
@@ -381,14 +381,15 @@ def _star_star_dict(context, array, input_node, funcdef):
 
 
 def _error_argument_count(funcdef, actual_count):
-    default_arguments = sum(1 for p in funcdef.params if p.default or p.star_count)
+    params = funcdef.get_params()
+    default_arguments = sum(1 for p in params if p.default or p.star_count)
 
     if default_arguments == 0:
         before = 'exactly '
     else:
-        before = 'from %s to ' % (len(funcdef.params) - default_arguments)
+        before = 'from %s to ' % (len(params) - default_arguments)
     return ('TypeError: %s() takes %s%s arguments (%s given).'
-            % (funcdef.name, before, len(funcdef.params), actual_count))
+            % (funcdef.name, before, len(params), actual_count))
 
 
 def create_default_param(execution_context, param):
diff --git a/jedi/evaluate/pep0484.py b/jedi/evaluate/pep0484.py
index c87a967a..caef06b4 100644
--- a/jedi/evaluate/pep0484.py
+++ b/jedi/evaluate/pep0484.py
@@ -94,7 +94,7 @@ def py__annotations__(funcdef):
         dct = {'return': return_annotation}
     else:
         dct = {}
-    for function_param in funcdef.params:
+    for function_param in funcdef.get_params():
         param_annotation = function_param.annotation
         if param_annotation is not None:
             dct[function_param.name.value] = param_annotation
diff --git a/jedi/evaluate/representation.py b/jedi/evaluate/representation.py
index fe8d5cfa..80697806 100644
--- a/jedi/evaluate/representation.py
+++ b/jedi/evaluate/representation.py
@@ -170,7 +170,7 @@ class ClassContext(use_metaclass(CachedMetaClass, context.TreeContext)):
     def get_params(self):
         from jedi.evaluate.instance import AnonymousInstance
         anon = AnonymousInstance(self.evaluator, self.parent_context, self)
-        return [AnonymousInstanceParamName(anon, param.name) for param in self.funcdef.params]
+        return [AnonymousInstanceParamName(anon, param.name) for param in self.funcdef.get_params()]
 
     def get_filters(self, search_global, until_position=None, origin_scope=None, is_instance=False):
         if search_global:
@@ -291,7 +291,8 @@ class FunctionContext(use_metaclass(CachedMetaClass, context.TreeContext)):
 
     def get_param_names(self):
         function_execution = self.get_function_execution()
-        return [ParamName(function_execution, param.name) for param in self.tree_node.params]
+        return [ParamName(function_execution, param.name)
+                for param in self.tree_node.get_params()]
 
 
 class FunctionExecutionContext(context.TreeContext):
diff --git a/jedi/parser_utils.py b/jedi/parser_utils.py
index d97f0708..59c6408e 100644
--- a/jedi/parser_utils.py
+++ b/jedi/parser_utils.py
@@ -155,7 +155,7 @@ def get_call_signature(funcdef, width=72, call_string=None):
         else:
             call_string = funcdef.name.value
     if funcdef.type == 'lambdef':
-        p = '(' + ''.join(param.get_code() for param in funcdef.params).strip() + ')'
+        p = '(' + ''.join(param.get_code() for param in funcdef.get_params()).strip() + ')'
     else:
         p = funcdef.children[2].get_code()
     code = call_string + p