diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 562f49574..094964b63 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -21,6 +21,8 @@ Changelog
     - ``usages`` deprecated, use ``find_references`` instead
     - ``jedi.names`` deprecated, use ``jedi.Script(...).names()``
 - ``BaseDefinition.goto_assignments`` renamed to ``BaseDefinition.goto``
+- Python 2 support deprecated. For this release it is best effort. Python 2 has
+  reached the end of its life and now it's just about a smooth transition.
 
 0.15.2 (2019-12-20)
 +++++++++++++++++++
diff --git a/jedi/api/completion.py b/jedi/api/completion.py
index 465dd4f72..0602244b7 100644
--- a/jedi/api/completion.py
+++ b/jedi/api/completion.py
@@ -18,6 +18,7 @@
 from jedi.inference.value import TreeInstance
 from jedi.inference.gradual.conversion import convert_values
 from jedi.parser_utils import cut_value_at_position
+from jedi.plugins import plugin_manager
 
 
 def get_signature_param_names(signatures):
@@ -74,6 +75,13 @@ def get_flow_scope_node(module_node, position):
     return node
 
 
+@plugin_manager.decorate()
+def complete_param_names(context, function_name, decorator_nodes):
+    # Basically there's no way to do param completion. The plugins are
+    # responsible for this.
+    return []
+
+
 class Completion:
     def __init__(self, inference_state, module_context, code_lines, position,
                  signatures_callback, fuzzy=False):
@@ -216,6 +224,8 @@ def _complete_python(self, leaf):
             elif nonterminals[-1] in ('trailer', 'dotted_name') and nodes[-1] == '.':
                 dot = self._module_node.get_leaf_for_position(self._position)
                 completion_names += self._complete_trailer(dot.get_previous_leaf())
+            elif self._is_parameter_completion():
+                completion_names += self._complete_params(leaf)
             else:
                 completion_names += self._complete_global_scope()
                 completion_names += self._complete_inherited(is_function=False)
@@ -234,6 +244,41 @@ def _complete_python(self, leaf):
 
         return completion_names
 
+    def _is_parameter_completion(self):
+        tos = self.stack[-1]
+        if tos.nonterminal == 'lambdef' and len(tos.nodes) == 1:
+            # We are at the position `lambda `, where basically the next node
+            # is a param.
+            return True
+        if tos.nonterminal in 'parameters':
+            # Basically we are at the position `foo(`, there's nothing there
+            # yet, so we have no `typedargslist`.
+            return True
+        # var args is for lambdas and typed args for normal functions
+        return tos.nonterminal in ('typedargslist', 'varargslist') and tos.nodes[-1] == ','
+
+    def _complete_params(self, leaf):
+        stack_node = self.stack[-2]
+        if stack_node.nonterminal == 'parameters':
+            stack_node = self.stack[-3]
+        if stack_node.nonterminal == 'funcdef':
+            context = get_user_context(self._module_context, self._position)
+            node = search_ancestor(leaf, 'error_node', 'funcdef')
+            if node.type == 'error_node':
+                n = node.children[0]
+                if n.type == 'decorators':
+                    decorators = n.children
+                elif n.type == 'decorator':
+                    decorators = [n]
+                else:
+                    decorators = []
+            else:
+                decorators = node.get_decorators()
+            function_name = stack_node.nodes[1]
+
+            return complete_param_names(context, function_name.value, decorators)
+        return []
+
     def _complete_keywords(self, allowed_transitions):
         for k in allowed_transitions:
             if isinstance(k, str) and k.isalpha():
diff --git a/jedi/file_io.py b/jedi/file_io.py
index 37d958ea5..012bff414 100644
--- a/jedi/file_io.py
+++ b/jedi/file_io.py
@@ -13,6 +13,12 @@ def list(self):
     def get_file_io(self, name):
         raise NotImplementedError
 
+    def get_parent_folder(self):
+        raise NotImplementedError
+
+    def __repr__(self):
+        return '<%s: %s>' % (self.__class__.__name__, self.path)
+
 
 class FolderIO(AbstractFolderIO):
     def list(self):
@@ -21,6 +27,9 @@ def list(self):
     def get_file_io(self, name):
         return FileIO(os.path.join(self.path, name))
 
+    def get_parent_folder(self):
+        return FolderIO(os.path.dirname(self.path))
+
 
 class FileIOFolderMixin(object):
     def get_parent_folder(self):
diff --git a/jedi/inference/__init__.py b/jedi/inference/__init__.py
index e3c2db7ad..42d5c56a9 100644
--- a/jedi/inference/__init__.py
+++ b/jedi/inference/__init__.py
@@ -169,6 +169,8 @@ def infer(self, context, name):
                 return imports.infer_import(context, name)
             if type_ == 'with_stmt':
                 return tree_name_to_values(self, context, name)
+            elif type_ == 'param':
+                return context.py__getattribute__(name.value, position=name.end_pos)
         else:
             result = follow_error_node_imports_if_possible(context, name)
             if result is not None:
diff --git a/jedi/inference/filters.py b/jedi/inference/filters.py
index 9001484b7..9bac3d897 100644
--- a/jedi/inference/filters.py
+++ b/jedi/inference/filters.py
@@ -246,24 +246,18 @@ def __repr__(self):
         return '%s(%s)' % (self.__class__.__name__, ', '.join(str(f) for f in self._filters))
 
 
-class _BuiltinMappedMethod(Value):
+class _BuiltinMappedMethod(ValueWrapper):
     """``Generator.__next__`` ``dict.values`` methods and so on."""
     api_type = u'function'
 
-    def __init__(self, builtin_value, method, builtin_func):
-        super(_BuiltinMappedMethod, self).__init__(
-            builtin_value.inference_state,
-            parent_context=builtin_value
-        )
+    def __init__(self, value, method, builtin_func):
+        super(_BuiltinMappedMethod, self).__init__(builtin_func)
+        self._value = value
         self._method = method
-        self._builtin_func = builtin_func
 
     def py__call__(self, arguments):
         # TODO add TypeError if params are given/or not correct.
-        return self._method(self.parent_context)
-
-    def __getattr__(self, name):
-        return getattr(self._builtin_func, name)
+        return self._method(self._value)
 
 
 class SpecialMethodFilter(DictFilter):
diff --git a/jedi/inference/gradual/typing.py b/jedi/inference/gradual/typing.py
index e1bf15661..861cc9f02 100644
--- a/jedi/inference/gradual/typing.py
+++ b/jedi/inference/gradual/typing.py
@@ -322,6 +322,11 @@ def __init__(self, inference_state, parent_context, tree_node, type_value_set):
     def py__call__(self, arguments):
         return self._type_value_set.execute_annotation()
 
+    @property
+    def name(self):
+        from jedi.inference.compiled.value import CompiledValueName
+        return CompiledValueName(self, 'NewType')
+
 
 class CastFunction(BaseTypingValue):
     @repack_with_argument_clinic('type, object, /')
diff --git a/jedi/inference/imports.py b/jedi/inference/imports.py
index e28ce314d..ab2c75bd2 100644
--- a/jedi/inference/imports.py
+++ b/jedi/inference/imports.py
@@ -505,7 +505,7 @@ def _load_builtin_module(inference_state, import_names=None, sys_path=None):
     return module
 
 
-def _load_module_from_path(inference_state, file_io, base_names):
+def load_module_from_path(inference_state, file_io, base_names=None):
     """
     This should pretty much only be used for get_modules_containing_name. It's
     here to ensure that a random path is still properly loaded into the Jedi
@@ -552,7 +552,7 @@ def check_fs(file_io, base_names):
         if name not in code:
             return None
         new_file_io = KnownContentFileIO(file_io.path, code)
-        m = _load_module_from_path(inference_state, new_file_io, base_names)
+        m = load_module_from_path(inference_state, new_file_io, base_names)
         if isinstance(m, compiled.CompiledObject):
             return None
         return m.as_context()
diff --git a/jedi/inference/names.py b/jedi/inference/names.py
index 56d5daf61..effc2410b 100644
--- a/jedi/inference/names.py
+++ b/jedi/inference/names.py
@@ -9,6 +9,7 @@
 from jedi.inference import docstrings
 from jedi.cache import memoize_method
 from jedi.inference.helpers import deep_ast_copy, infer_call_of_leaf
+from jedi.plugins import plugin_manager
 
 
 def _merge_name_docs(names):
@@ -482,6 +483,11 @@ def infer(self):
 
 
 class AnonymousParamName(_ActualTreeParamName):
+    @plugin_manager.decorate(name='goto_anonymous_param')
+    def goto(self):
+        return super(AnonymousParamName, self).goto()
+
+    @plugin_manager.decorate(name='infer_anonymous_param')
     def infer(self):
         values = super(AnonymousParamName, self).infer()
         if values:
diff --git a/jedi/inference/value/function.py b/jedi/inference/value/function.py
index dfe190f90..18963f648 100644
--- a/jedi/inference/value/function.py
+++ b/jedi/inference/value/function.py
@@ -277,17 +277,19 @@ def merge_yield_values(self, is_async=False):
             for lazy_value in self.get_yield_lazy_values()
         )
 
+    def is_generator(self):
+        return bool(get_yield_exprs(self.inference_state, self.tree_node))
+
     def infer(self):
         """
         Created to be used by inheritance.
         """
         inference_state = self.inference_state
         is_coroutine = self.tree_node.parent.type in ('async_stmt', 'async_funcdef')
-        is_generator = bool(get_yield_exprs(inference_state, self.tree_node))
         from jedi.inference.gradual.base import GenericClass
 
         if is_coroutine:
-            if is_generator:
+            if self.is_generator():
                 if inference_state.environment.version_info < (3, 6):
                     return NO_VALUES
                 async_generator_classes = inference_state.typing_module \
@@ -312,7 +314,7 @@ def infer(self):
                     GenericClass(c, TupleGenericManager(generics)) for c in async_classes
                 ).execute_annotation()
         else:
-            if is_generator:
+            if self.is_generator():
                 return ValueSet([iterable.Generator(inference_state, self)])
             else:
                 return self.get_return_values()
diff --git a/jedi/plugins/__init__.py b/jedi/plugins/__init__.py
index df106cfca..23588bd44 100644
--- a/jedi/plugins/__init__.py
+++ b/jedi/plugins/__init__.py
@@ -14,18 +14,18 @@ def register(self, *plugins):
         self._registered_plugins.extend(plugins)
         self._build_functions()
 
-    def decorate(self):
+    def decorate(self, name=None):
         def decorator(callback):
             @wraps(callback)
             def wrapper(*args, **kwargs):
-                return built_functions[name](*args, **kwargs)
+                return built_functions[public_name](*args, **kwargs)
 
-            name = callback.__name__
+            public_name = name or callback.__name__
 
-            assert name not in self._built_functions
+            assert public_name not in self._built_functions
             built_functions = self._built_functions
-            built_functions[name] = callback
-            self._cached_base_callbacks[name] = callback
+            built_functions[public_name] = callback
+            self._cached_base_callbacks[public_name] = callback
 
             return wrapper
 
diff --git a/jedi/plugins/pytest.py b/jedi/plugins/pytest.py
new file mode 100644
index 000000000..08ff09050
--- /dev/null
+++ b/jedi/plugins/pytest.py
@@ -0,0 +1,133 @@
+from parso.python.tree import search_ancestor
+from jedi._compatibility import FileNotFoundError
+from jedi.inference.cache import inference_state_method_cache
+from jedi.inference.imports import load_module_from_path
+from jedi.inference.filters import ParserTreeFilter
+from jedi.inference.base_value import NO_VALUES, ValueSet
+
+
+def execute(callback):
+    def wrapper(value, arguments):
+        # This might not be necessary anymore in pytest 4/5, definitely needed
+        # for pytest 3.
+        if value.py__name__() == 'fixture' \
+                and value.parent_context.py__name__() == '_pytest.fixtures':
+            return NO_VALUES
+
+        return callback(value, arguments)
+    return wrapper
+
+
+def infer_anonymous_param(func):
+    def get_returns(value):
+        if value.tree_node.annotation is not None:
+            return value.execute_with_values()
+
+        # In pytest we need to differentiate between generators and normal
+        # returns.
+        # Parameters still need to be anonymous, .as_context() ensures that.
+        function_context = value.as_context()
+        if function_context.is_generator():
+            return function_context.merge_yield_values()
+        else:
+            return function_context.get_return_values()
+
+    def wrapper(param_name):
+        if _is_a_pytest_param(param_name):
+            module = param_name.get_root_context()
+            fixtures = _goto_pytest_fixture(module, param_name.string_name)
+            if fixtures:
+                return ValueSet.from_sets(
+                    get_returns(value)
+                    for fixture in fixtures
+                    for value in fixture.infer()
+                )
+        return func(param_name)
+    return wrapper
+
+
+def goto_anonymous_param(func):
+    def wrapper(param_name):
+        if _is_a_pytest_param(param_name):
+            names = _goto_pytest_fixture(param_name.get_root_context(), param_name.string_name)
+            if names:
+                return names
+        return func(param_name)
+    return wrapper
+
+
+def complete_param_names(func):
+    def wrapper(context, func_name, decorator_nodes):
+        module_context = context.get_root_context()
+        if _is_pytest_func(func_name, decorator_nodes):
+            names = []
+            for module_context in _iter_pytest_modules(module_context):
+                names += FixtureFilter(module_context).values()
+            if names:
+                return names
+        return func(context, func_name, decorator_nodes)
+    return wrapper
+
+
+def _goto_pytest_fixture(module_context, name):
+    for module_context in _iter_pytest_modules(module_context):
+        names = FixtureFilter(module_context).get(name)
+        if names:
+            return names
+
+
+def _is_a_pytest_param(param_name):
+    """
+    Pytest params are either in a `test_*` function or have a pytest fixture
+    with the decorator @pytest.fixture.
+
+    This is a heuristic and will work in most cases.
+    """
+    funcdef = search_ancestor(param_name.tree_name, 'funcdef')
+    if funcdef is None:  # A lambda
+        return False
+    decorators = funcdef.get_decorators()
+    return _is_pytest_func(funcdef.name.value, decorators)
+
+
+def _is_pytest_func(func_name, decorator_nodes):
+    return func_name.startswith('test_') \
+        or any('fixture' in n.get_code() for n in decorator_nodes)
+
+
+@inference_state_method_cache()
+def _iter_pytest_modules(module_context):
+    yield module_context
+
+    folder = module_context.get_value().file_io.get_parent_folder()
+    sys_path = module_context.inference_state.get_sys_path()
+    while any(folder.path.startswith(p) for p in sys_path):
+        file_io = folder.get_file_io('conftest.py')
+        try:
+            m = load_module_from_path(module_context.inference_state, file_io)
+            yield m.as_context()
+        except FileNotFoundError:
+            pass
+        folder = folder.get_parent_folder()
+
+
+class FixtureFilter(ParserTreeFilter):
+    def _filter(self, names):
+        for name in super(FixtureFilter, self)._filter(names):
+            funcdef = name.parent
+            if funcdef.type == 'funcdef':
+                # Class fixtures are not supported
+                decorated = funcdef.parent
+                if decorated.type == 'decorated' and self._is_fixture(decorated):
+                    yield name
+
+    def _is_fixture(self, decorated):
+        for decorator in decorated.children:
+            dotted_name = decorator.children[1]
+            # A heuristic, this makes it faster.
+            if 'fixture' in dotted_name.get_code():
+                for value in self.parent_context.infer_node(dotted_name):
+                    if value.name.get_qualified_names(include_module_names=True) \
+                            == ('_pytest', 'fixtures', 'fixture'):
+                        return True
+        return False
diff --git a/jedi/plugins/registry.py b/jedi/plugins/registry.py
index 239132446..b39cbbe97 100644
--- a/jedi/plugins/registry.py
+++ b/jedi/plugins/registry.py
@@ -4,7 +4,8 @@
 
 from jedi.plugins import stdlib
 from jedi.plugins import flask
+from jedi.plugins import pytest
 from jedi.plugins import plugin_manager
 
 
-plugin_manager.register(stdlib, flask)
+plugin_manager.register(stdlib, flask, pytest)
diff --git a/test/completion/basic.py b/test/completion/basic.py
index a74ca81c1..28089debe 100644
--- a/test/completion/basic.py
+++ b/test/completion/basic.py
@@ -299,6 +299,56 @@ def __init__(self, my_attr):
     for x in e.my_attr:
         pass
 
+# -----------------
+# params
+# -----------------
+
+my_param = 1
+#? 9 str()
+def foo1(my_param):
+    my_param = 3.0
+foo1("")
+
+my_type = float()
+#? 20 float()
+def foo2(my_param: my_type):
+    pass
+foo2("")
+#? 20 int()
+def foo3(my_param=my_param):
+    pass
+foo3("")
+
+some_default = ''
+#? []
+def foo(my_t
+#? []
+def foo(my_t, my_ty
+#? ['some_default']
+def foo(my_t=some_defa
+#? ['some_default']
+def foo(my_t=some_defa, my_t2=some_defa
+
+# python > 2.7
+
+#? ['my_type']
+def foo(my_t: lala=some_defa, my_t2: my_typ
+#? ['my_type']
+def foo(my_t: lala=some_defa, my_t2: my_typ
+#? []
+def foo(my_t: lala=some_defa, my_t
+
+#? []
+lambda my_t
+#? []
+lambda my_, my_t
+#? ['some_default']
+lambda x=some_defa
+#? ['some_default']
+lambda y, x=some_defa
+
+# Just make sure we're not in some weird parsing recovery after opening brackets
+def  
 
 # -----------------
 # continuations
diff --git a/test/completion/completion.py b/test/completion/completion.py
index b254e8d3f..f509a19c7 100644
--- a/test/completion/completion.py
+++ b/test/completion/completion.py
@@ -20,7 +20,7 @@ def x():
 class MyClass:
     @pass_decorator
     def x(foo,
-#? 5 ["tuple"]
+#? 5 []
 tuple,
           ):
         return 1
diff --git a/test/completion/conftest.py b/test/completion/conftest.py
new file mode 100644
index 000000000..c9646b9b9
--- /dev/null
+++ b/test/completion/conftest.py
@@ -0,0 +1,17 @@
+# Exists only for completion/pytest.py
+
+import pytest
+
+
+@pytest.fixture()
+def my_other_conftest_fixture():
+    return 1.0
+
+
+@pytest.fixture()
+def my_conftest_fixture(my_other_conftest_fixture):
+    return my_other_conftest_fixture
+
+
+def my_not_existing_fixture():
+    return 3  # Just a normal function
diff --git a/test/completion/parser.py b/test/completion/parser.py
index db88824fd..e0159cac4 100644
--- a/test/completion/parser.py
+++ b/test/completion/parser.py
@@ -40,4 +40,4 @@ def with_param(
 class Foo(object):
     @property
     #? ['str']
-    def bar(str
+    def bar(x=str
diff --git a/test/completion/pytest.py b/test/completion/pytest.py
new file mode 100644
index 000000000..bb48387e3
--- /dev/null
+++ b/test/completion/pytest.py
@@ -0,0 +1,118 @@
+# python > 2.7
+import pytest
+from pytest import fixture
+
+
+@pytest.fixture(scope='module')
+def my_fixture() -> str:
+    pass
+
+
+@fixture
+def my_simple_fixture():
+    return 1
+
+
+@fixture
+def my_yield_fixture():
+    yield 1
+
+
+@fixture
+class MyClassFixture():
+    pass
+
+# -----------------
+# goto/infer
+# -----------------
+
+#! 18 ['def my_conftest_fixture']
+def test_x(my_conftest_fixture, my_fixture, my_not_existing_fixture, my_yield_fixture):
+    #? str()
+    my_fixture
+    #? int()
+    my_yield_fixture
+    #?
+    my_not_existing_fixture
+    #? float()
+    return my_conftest_fixture
+
+#? 18 float()
+def test_x(my_conftest_fixture, my_fixture):
+    pass
+
+
+#! 18 ['param MyClassFixture']
+def test_x(MyClassFixture):
+    #?
+    MyClassFixture
+
+#? 15
+def lala(my_fixture):
+    pass
+
+@pytest.fixture
+#? 15 str()
+def lala(my_fixture):
+    pass
+
+#! 15 ['param my_fixture']
+def lala(my_fixture):
+    pass
+
+@pytest.fixture
+#! 15 ['def my_fixture']
+def lala(my_fixture):
+    pass
+
+# -----------------
+# completion
+# -----------------
+
+#? 34 ['my_fixture']
+def test_x(my_simple_fixture, my_fixture):
+    return
+#? 34 ['my_fixture']
+def test_x(my_simple_fixture, my_fixture):
+    return
+#? ['my_fixture']
+def test_x(my_simple_fixture, my_f
+    return
+#? 18 ['my_simple_fixture']
+def test_x(my_simple_fixture):
+    return
+#? ['my_simple_fixture']
+def test_x(my_simp
+    return
+#? ['my_conftest_fixture']
+def test_x(my_con
+    return
+#? 18 ['my_conftest_fixture']
+def test_x(my_conftest_fixture):
+    return
+
+#? []
+def lala(my_con
+    return
+
+@pytest.fixture
+#? ['my_conftest_fixture']
+def lala(my_con
+    return
+
+@pytest.fixture
+#? 15 ['my_conftest_fixture']
+def lala(my_con):
+    return
+
+@pytest.fixture
+@some_decorator
+#? ['my_conftest_fixture']
+def lala(my_con
+    return
+
+@pytest.fixture
+@some_decorator
+#? 15 ['my_conftest_fixture']
+def lala(my_con):
+    return
diff --git a/test/test_inference/test_imports.py b/test/test_inference/test_imports.py
index 5d628d056..935827438 100644
--- a/test/test_inference/test_imports.py
+++ b/test/test_inference/test_imports.py
@@ -342,7 +342,7 @@ def test_get_modules_containing_name(inference_state, path, goal, is_package):
 )
 def test_load_module_from_path(inference_state, path, base_names, is_package, names):
     file_io = KnownContentFileIO(path, '')
-    m = imports._load_module_from_path(inference_state, file_io, base_names)
+    m = imports.load_module_from_path(inference_state, file_io, base_names)
     assert m.is_package() == is_package
     assert m.string_names == names