diff --git a/parso/python/tree.py b/parso/python/tree.py
index 3865781..7a2ab12 100644
--- a/parso/python/tree.py
+++ b/parso/python/tree.py
@@ -433,7 +433,10 @@ def _create_params(parent, argslist_list):
     elif first == '*':
         return [first]
     else:  # argslist is a `typedargslist` or a `varargslist`.
-        children = first.children
+        if first.type == 'tfpdef':
+            children = [first]
+        else:
+            children = first.children
         new_children = []
         start = 0
         # Start with offset 1, because the end is higher.
@@ -958,8 +961,10 @@ class Param(PythonBaseNode):
         The default is the test node that appears after the `=`. Is `None` in
         case no default is present.
         """
+        has_comma = self.children[-1] == ','
         try:
-            return self.children[int(self.children[0] in ('*', '**')) + 2]
+            if self.children[-2 - int(has_comma)] == '=':
+                return self.children[-1 - int(has_comma)]
         except IndexError:
             return None
 
diff --git a/test/test_parser_tree.py b/test/test_parser_tree.py
index 2bf546f..dd8a933 100644
--- a/test/test_parser_tree.py
+++ b/test/test_parser_tree.py
@@ -69,3 +69,40 @@ def test_end_pos_line(each_version):
     for i, simple_stmt in enumerate(module.children[:-1]):
         expr_stmt = simple_stmt.children[0]
         assert expr_stmt.end_pos == (i + 1, i + 3)
+
+
+def test_default_param(each_version):
+    func = parse('def x(foo=42): pass', version=each_version).children[0]
+    param, = func.params
+    assert param.default.value == '42'
+    assert param.annotation is None
+    assert not param.star_count
+
+
+def test_annotation_param(each_py3_version):
+    func = parse('def x(foo: 3): pass', version=each_py3_version).children[0]
+    param, = func.params
+    assert param.default is None
+    assert param.annotation.value == '3'
+    assert not param.star_count
+
+
+def test_annotation_params(each_py3_version):
+    func = parse('def x(foo: 3, bar: 4): pass', version=each_py3_version).children[0]
+    param1, param2 = func.params
+
+    assert param1.default is None
+    assert param1.annotation.value == '3'
+    assert not param1.star_count
+
+    assert param2.default is None
+    assert param2.annotation.value == '4'
+    assert not param2.star_count
+
+
+def test_default_and_annotation_param(each_py3_version):
+    func = parse('def x(foo:3=42): pass', version=each_py3_version).children[0]
+    param, = func.params
+    assert param.default.value == '42'
+    assert param.annotation.value == '3'
+    assert not param.star_count