diff --git a/jedi/evaluate/names.py b/jedi/evaluate/names.py
index f7e6b11a..1789a23e 100644
--- a/jedi/evaluate/names.py
+++ b/jedi/evaluate/names.py
@@ -168,14 +168,34 @@ class ParamNameInterface(object):
         raise NotImplementedError
 
 
-class ParamName(ParamNameInterface, AbstractTreeName):
-    def __init__(self, parent_context, tree_name):
-        self.parent_context = parent_context
-        self.tree_name = tree_name
+class BaseTreeParamName(ParamNameInterface, AbstractTreeName):
+    def get_default_node(self):
+        return None
 
+    def get_annotation_node(self):
+        return None
+
+    def to_string(self):
+        output = self._kind_string() + self.string_name
+        annotation = self.get_annotation_node()
+        default = self.get_default_node()
+        if annotation is not None:
+            output += ': ' + annotation.get_code(include_prefix=False)
+        if default is not None:
+            output += '=' + default.get_code(include_prefix=False)
+        return output
+
+
+class ParamName(BaseTreeParamName):
     def _get_param_node(self):
         return search_ancestor(self.tree_name, 'param')
 
+    def get_annotation_node(self):
+        return self._get_param_node().annotation
+
+    def get_default_node(self):
+        return self._get_param_node().default
+
     @property
     def string_name(self):
         name = self.tree_name.value
@@ -213,15 +233,6 @@ class ParamName(ParamNameInterface, AbstractTreeName):
                         param_appeared = True
         return Parameter.POSITIONAL_OR_KEYWORD
 
-    def to_string(self):
-        output = self._kind_string() + self.string_name
-        param_node = self._get_param_node()
-        if param_node.annotation is not None:
-            output += ': ' + param_node.annotation.get_code(include_prefix=False)
-        if param_node.default is not None:
-            output += '=' + param_node.default.get_code(include_prefix=False)
-        return output
-
     def infer(self):
         return self.get_param().infer()
 
diff --git a/jedi/plugins/stdlib.py b/jedi/plugins/stdlib.py
index 06cd7f46..db09896c 100644
--- a/jedi/plugins/stdlib.py
+++ b/jedi/plugins/stdlib.py
@@ -11,7 +11,7 @@ compiled module that returns the types for C-builtins.
 """
 import parso
 
-from jedi._compatibility import force_unicode
+from jedi._compatibility import force_unicode, Parameter
 from jedi import debug
 from jedi.evaluate.utils import safe_property
 from jedi.evaluate.helpers import get_str_or_none
@@ -27,10 +27,11 @@ from jedi.evaluate.context import ClassContext, ModuleContext, \
 from jedi.evaluate.context import iterable
 from jedi.evaluate.lazy_context import LazyTreeContext, LazyKnownContext, \
     LazyKnownContexts
-from jedi.evaluate.names import ContextName
+from jedi.evaluate.names import ContextName, BaseTreeParamName
 from jedi.evaluate.syntax_tree import is_string
 from jedi.evaluate.filters import AttributeOverwrite, publish_method, \
     ParserTreeFilter, DictFilter
+from jedi.evaluate.signature import AbstractSignature
 
 
 # Copied from Python 3.6's stdlib.
@@ -531,24 +532,54 @@ def _dataclass(obj, arguments):
 
 class DataclassWrapper(ContextWrapper):
     def get_signatures(self):
-        params = []
-        for cls in reversed(self._wrapped_context.py__mro__()):
+        param_names = []
+        for cls in reversed(list(self._wrapped_context.py__mro__())):
             if isinstance(cls, ClassContext) and not cls.is_stub():
                 filter_ = cls.get_global_filter()
-                print(filter_)
                 for name in filter_.values():
                     d = name.tree_name.get_definition()
-                    if d.type == 'expr_stmt' and d.children[1].type == 'annassign':
-                        params.append()
-        return [DataclassSignature(cls, params)]
+                    annassign = d.children[1]
+                    if d.type == 'expr_stmt' and annassign.type == 'annassign':
+                        if len(annassign.children) < 4:
+                            default = None
+                        else:
+                            default = annassign.children[3]
+                        param_names.append(DataclassParamName(
+                            parent_context=cls.parent_context,
+                            tree_name=name.tree_name,
+                            annotation_node=annassign.children[1],
+                            default_node=default,
+                        ))
+        return [DataclassSignature(cls, param_names)]
 
 
 class DataclassSignature(AbstractSignature):
-    def __init__(self, context, params):
+    def __init__(self, context, param_names):
         super(DataclassSignature, self).__init__(context)
-        self._params = params
+        self._param_names = param_names
 
     def get_param_names(self):
+        return self._param_names
+
+
+class DataclassParamName(BaseTreeParamName):
+    def __init__(self, parent_context, tree_name, annotation_node, default_node):
+        super(DataclassParamName, self).__init__(parent_context, tree_name)
+        self._annotation_node = annotation_node
+        self._default_node = default_node
+
+    def get_kind(self):
+        return Parameter.POSITIONAL_OR_KEYWORD
+    #TODO get_param?
+
+    def get_annotation_node(self):
+        return self._annotation_node
+
+    def get_default_node(self):
+        return self._default_node
+
+    def infer(self):
+        return NO_CONTEXTS  # TODO implement
 
 
 class ItemGetterCallable(ContextWrapper):