diff --git a/.travis.yml b/.travis.yml
index 1588ee1b7..e16e26897 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ python:
 
 env:
   - JEDI_TEST_ENVIRONMENT=38
+  - JEDI_TEST_ENVIRONMENT=39
   - JEDI_TEST_ENVIRONMENT=37
   - JEDI_TEST_ENVIRONMENT=36
   - JEDI_TEST_ENVIRONMENT=interpreter
@@ -47,9 +48,15 @@ script:
           # Only required for JEDI_TEST_ENVIRONMENT=38, because it's not always
           # available.
           download_name=python-$test_env_version
-          wget https://s3.amazonaws.com/travis-python-archives/binaries/ubuntu/16.04/x86_64/$download_name.tar.bz2
-          sudo tar xjf $download_name.tar.bz2 --directory / opt/python
-          ln -s "/opt/python/${test_env_version}/bin/python" /home/travis/bin/$python_bin
+          if [ "$JEDI_TEST_ENVIRONMENT" == "39" ]; then
+            wget https://storage.googleapis.com/travis-ci-language-archives/python/binaries/ubuntu/16.04/x86_64/python-3.9-dev.tar.bz2
+            sudo tar xjf python-3.9-dev.tar.bz2 --directory / opt/python
+            ln -s "/opt/python/3.9-dev/bin/python" /home/travis/bin/python3.9
+          else
+            wget https://s3.amazonaws.com/travis-python-archives/binaries/ubuntu/16.04/x86_64/$download_name.tar.bz2
+            sudo tar xjf $download_name.tar.bz2 --directory / opt/python
+            ln -s "/opt/python/${test_env_version}/bin/python" /home/travis/bin/$python_bin
+          fi
         elif [ "${python_path#/opt/pyenv/shims}" != "$python_path" ]; then
           # Activate pyenv version (required with JEDI_TEST_ENVIRONMENT=36).
           pyenv_bin="$(pyenv whence --path "$python_bin" | head -n1)"
diff --git a/jedi/api/__init__.py b/jedi/api/__init__.py
index a0430e90d..34718881d 100644
--- a/jedi/api/__init__.py
+++ b/jedi/api/__init__.py
@@ -160,7 +160,7 @@ def __init__(self, code=None, line=None, column=None, path=None,
         self._module_node, code = self._inference_state.parse_and_get_code(
             code=code,
             path=self.path,
-            use_latest_grammar=path and path.suffix == 'pyi',
+            use_latest_grammar=path and path.suffix == '.pyi',
             cache=False,  # No disk cache, because the current script often changes.
             diff_cache=settings.fast_parser,
             cache_path=settings.cache_directory,
@@ -196,6 +196,7 @@ def _get_module(self):
             # We are in a stub file. Try to load the stub properly.
             stub_module = load_proper_stub_module(
                 self._inference_state,
+                self._inference_state.latest_grammar,
                 file_io,
                 names,
                 self._module_node
@@ -281,6 +282,11 @@ def infer(self, line=None, column=None, *, only_stubs=False, prefer_stubs=False)
             leaf = self._module_node.get_leaf_for_position(pos)
             if leaf is None or leaf.type == 'string':
                 return []
+            if leaf.end_pos == (line, column) and leaf.type == 'operator':
+                next_ = leaf.get_next_leaf()
+                if next_.start_pos == leaf.end_pos \
+                        and next_.type in ('number', 'string', 'keyword'):
+                    leaf = next_
 
         context = self._get_module_context().create_context(leaf)
 
diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index a8d9fb19c..42aac726c 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -749,6 +749,24 @@ def type(self):
 
         return super().type
 
+    def get_completion_prefix_length(self):
+        """
+        Returns the length of the prefix being completed.
+        For example, completing ``isinstance``::
+
+            isinstan# <-- Cursor is here
+
+        would return 8, because len('isinstan') == 8.
+
+        Assuming the following function definition::
+
+            def foo(param=0):
+                pass
+
+        completing ``foo(par`` would return 3.
+        """
+        return self._like_name_length
+
     def __repr__(self):
         return '<%s: %s>' % (type(self).__name__, self._name.get_public_name())
 
diff --git a/jedi/api/project.py b/jedi/api/project.py
index 415543144..8c438f26e 100644
--- a/jedi/api/project.py
+++ b/jedi/api/project.py
@@ -366,8 +366,11 @@ def __repr__(self):
 
 def _is_potential_project(path):
     for name in _CONTAINS_POTENTIAL_PROJECT:
-        if path.joinpath(name).exists():
-            return True
+        try:
+            if path.joinpath(name).exists():
+                return True
+        except OSError:
+            continue
     return False
 
 
diff --git a/jedi/inference/compiled/value.py b/jedi/inference/compiled/value.py
index 1b34b123a..88732f011 100644
--- a/jedi/inference/compiled/value.py
+++ b/jedi/inference/compiled/value.py
@@ -324,8 +324,7 @@ def __init__(self, inference_state, parent_value, name):
         self.string_name = name
 
     def py__doc__(self):
-        value, = self.infer()
-        return value.py__doc__()
+        return self.infer_compiled_value().py__doc__()
 
     def _get_qualified_names(self):
         parent_qualified_names = self.parent_context.get_qualified_names()
@@ -349,16 +348,12 @@ def __repr__(self):
 
     @property
     def api_type(self):
-        api = self.infer()
-        # If we can't find the type, assume it is an instance variable
-        if not api:
-            return "instance"
-        return next(iter(api)).api_type
+        return self.infer_compiled_value().api_type
 
-    @memoize_method
     def infer(self):
         return ValueSet([self.infer_compiled_value()])
 
+    @memoize_method
     def infer_compiled_value(self):
         return create_from_name(self._inference_state, self._parent_value, self.string_name)
 
diff --git a/jedi/inference/docstrings.py b/jedi/inference/docstrings.py
index ee7a8d895..80afbecfa 100644
--- a/jedi/inference/docstrings.py
+++ b/jedi/inference/docstrings.py
@@ -113,7 +113,7 @@ def _expand_typestr(type_str):
     elif type_str.startswith('{'):
         node = parse(type_str, version='3.7').children[0]
         if node.type == 'atom':
-            for leaf in node.children[1].children:
+            for leaf in getattr(node.children[1], "children", []):
                 if leaf.type == 'number':
                     if '.' in leaf.value:
                         yield 'float'
diff --git a/jedi/inference/gradual/typeshed.py b/jedi/inference/gradual/typeshed.py
index 6295294d7..a4b287868 100644
--- a/jedi/inference/gradual/typeshed.py
+++ b/jedi/inference/gradual/typeshed.py
@@ -279,8 +279,8 @@ def _try_to_load_stub_from_file(inference_state, python_value_set, file_io, impo
         return None
     else:
         return create_stub_module(
-            inference_state, python_value_set, stub_module_node, file_io,
-            import_names
+            inference_state, inference_state.latest_grammar, python_value_set,
+            stub_module_node, file_io, import_names
         )
 
 
@@ -294,7 +294,8 @@ def parse_stub_module(inference_state, file_io):
     )
 
 
-def create_stub_module(inference_state, python_value_set, stub_module_node, file_io, import_names):
+def create_stub_module(inference_state, grammar, python_value_set,
+                       stub_module_node, file_io, import_names):
     if import_names == ('typing',):
         module_cls = TypingModuleWrapper
     else:
@@ -306,7 +307,7 @@ def create_stub_module(inference_state, python_value_set, stub_module_node, file
         string_names=import_names,
         # The code was loaded with latest_grammar, so use
         # that.
-        code_lines=get_cached_code_lines(inference_state.latest_grammar, file_io.path),
+        code_lines=get_cached_code_lines(grammar, file_io.path),
         is_package=file_name == '__init__.pyi',
     )
     return stub_module_value
diff --git a/jedi/inference/gradual/utils.py b/jedi/inference/gradual/utils.py
index 1fc90e7f3..af3703c7a 100644
--- a/jedi/inference/gradual/utils.py
+++ b/jedi/inference/gradual/utils.py
@@ -3,7 +3,7 @@
 from jedi.inference.gradual.typeshed import TYPESHED_PATH, create_stub_module
 
 
-def load_proper_stub_module(inference_state, file_io, import_names, module_node):
+def load_proper_stub_module(inference_state, grammar, file_io, import_names, module_node):
     """
     This function is given a random .pyi file and should return the proper
     module.
@@ -27,7 +27,8 @@ def load_proper_stub_module(inference_state, file_io, import_names, module_node)
         actual_value_set = inference_state.import_module(import_names, prefer_stubs=False)
 
         stub = create_stub_module(
-            inference_state, actual_value_set, module_node, file_io, import_names
+            inference_state, grammar, actual_value_set,
+            module_node, file_io, import_names
         )
         inference_state.stub_module_cache[import_names] = stub
         return stub
diff --git a/jedi/inference/imports.py b/jedi/inference/imports.py
index 8309473fc..d2b42e438 100644
--- a/jedi/inference/imports.py
+++ b/jedi/inference/imports.py
@@ -533,8 +533,8 @@ def load_module_from_path(inference_state, file_io, import_names=None, is_packag
             values = NO_VALUES
 
         return create_stub_module(
-            inference_state, values, parse_stub_module(inference_state, file_io),
-            file_io, import_names
+            inference_state, inference_state.latest_grammar, values,
+            parse_stub_module(inference_state, file_io), file_io, import_names
         )
     else:
         module = _load_python_module(
diff --git a/jedi/inference/names.py b/jedi/inference/names.py
index 38be6f22f..2be1427c4 100644
--- a/jedi/inference/names.py
+++ b/jedi/inference/names.py
@@ -7,6 +7,7 @@
 from jedi.parser_utils import find_statement_documentation, clean_scope_docstring
 from jedi.inference.utils import unite
 from jedi.inference.base_value import ValueSet, NO_VALUES
+from jedi.inference.cache import inference_state_method_cache
 from jedi.inference import docstrings
 from jedi.cache import memoize_method
 from jedi.inference.helpers import deep_ast_copy, infer_call_of_leaf
@@ -331,6 +332,12 @@ def assignment_indexes(self):
             node = node.parent
         return indexes
 
+    @property
+    def inference_state(self):
+        # Used by the cache function below
+        return self.parent_context.inference_state
+
+    @inference_state_method_cache(default='')
     def py__doc__(self):
         api_type = self.api_type
         if api_type in ('function', 'class'):
diff --git a/jedi/inference/sys_path.py b/jedi/inference/sys_path.py
index 48b9ac897..e701686f5 100644
--- a/jedi/inference/sys_path.py
+++ b/jedi/inference/sys_path.py
@@ -171,8 +171,11 @@ def _get_paths_from_buildout_script(inference_state, buildout_script_path):
 
 def _get_parent_dir_with_file(path: Path, filename):
     for parent in path.parents:
-        if parent.joinpath(filename).is_file():
-            return parent
+        try:
+            if parent.joinpath(filename).is_file():
+                return parent
+        except OSError:
+            continue
     return None
 
 
diff --git a/jedi/inference/value/instance.py b/jedi/inference/value/instance.py
index 9514e01de..c2c203591 100644
--- a/jedi/inference/value/instance.py
+++ b/jedi/inference/value/instance.py
@@ -401,21 +401,10 @@ class AnonymousInstance(_BaseTreeInstance):
     _arguments = None
 
 
-class CompiledInstanceName(compiled.CompiledName):
-    def __init__(self, inference_state, instance, klass, name):
-        parent_value = klass.parent_context.get_value()
-        assert parent_value is not None, "How? Please reproduce and report"
-        super().__init__(
-            inference_state,
-            parent_value,
-            name.string_name
-        )
-        self._instance = instance
-        self._class_member_name = name
-
+class CompiledInstanceName(NameWrapper):
     @iterator_to_value_set
     def infer(self):
-        for result_value in self._class_member_name.infer():
+        for result_value in self._wrapped_name.infer():
             if result_value.api_type == 'function':
                 yield CompiledBoundMethod(result_value)
             else:
@@ -434,11 +423,7 @@ def values(self):
         return self._convert(self._class_filter.values())
 
     def _convert(self, names):
-        klass = self._class_filter.compiled_value
-        return [
-            CompiledInstanceName(self._instance.inference_state, self._instance, klass, n)
-            for n in names
-        ]
+        return [CompiledInstanceName(n) for n in names]
 
 
 class BoundMethod(FunctionMixin, ValueWrapper):
@@ -516,6 +501,18 @@ def parent_context(self):
     def get_defining_qualified_value(self):
         return self._instance
 
+    def infer(self):
+        stmt = search_ancestor(self.tree_name, 'expr_stmt')
+        if stmt is not None:
+            if stmt.children[1].type == "annassign":
+                from jedi.inference.gradual.annotation import infer_annotation
+                values = infer_annotation(
+                    self.parent_context, stmt.children[1].children[1]
+                ).execute_annotation()
+                if values:
+                    return values
+        return super().infer()
+
 
 class LazyInstanceClassName(NameWrapper):
     def __init__(self, instance, class_member_name):
diff --git a/jedi/plugins/stdlib.py b/jedi/plugins/stdlib.py
index fddde91f7..17f1df3bc 100644
--- a/jedi/plugins/stdlib.py
+++ b/jedi/plugins/stdlib.py
@@ -819,7 +819,8 @@ def wrapper(cls, metaclasses, is_instance):
                     and metaclass.get_root_context().py__name__() == 'enum':
                 filter_ = ParserTreeFilter(parent_context=cls.as_context())
                 return [DictFilter({
-                    name.string_name: EnumInstance(cls, name).name for name in filter_.values()
+                    name.string_name: EnumInstance(cls, name).name
+                    for name in filter_.values()
                 })]
         return func(cls, metaclasses, is_instance)
     return wrapper
@@ -837,6 +838,14 @@ def name(self):
         return ValueName(self, self._name.tree_name)
 
     def _get_wrapped_value(self):
+        n = self._name.string_name
+        if n.startswith('__') and n.endswith('__') or self._name.api_type == 'function':
+            inferred = self._name.infer()
+            if inferred:
+                return next(iter(inferred))
+            o, = self.inference_state.builtins_module.py__getattribute__('object')
+            return o
+
         value, = self._cls.execute_with_values()
         return value
 
diff --git a/test/completion/pep0484_basic.py b/test/completion/pep0484_basic.py
index 54ec87701..e20fe4408 100644
--- a/test/completion/pep0484_basic.py
+++ b/test/completion/pep0484_basic.py
@@ -179,3 +179,22 @@ def argskwargs(*args: int, **kwargs: float):
     next(iter(kwargs.keys()))
     #? float()
     kwargs['']
+
+
+class NotCalledClass:
+    def __init__(self, x):
+        self.x: int = x
+        self.y: int = ''
+        #? int()
+        self.x
+        #? int()
+        self.y
+        #? int()
+        self.y
+        self.z: int
+        self.z = ''
+        #? str() int()
+        self.z
+        self.w: float
+        #? float()
+        self.w
diff --git a/test/examples/import-recursion/cadquery_simple/__init__.py b/test/examples/import-recursion/cadquery_simple/__init__.py
new file mode 100644
index 000000000..e87c66328
--- /dev/null
+++ b/test/examples/import-recursion/cadquery_simple/__init__.py
@@ -0,0 +1 @@
+from .cq import selectors
diff --git a/test/examples/import-recursion/cadquery_simple/cq.py b/test/examples/import-recursion/cadquery_simple/cq.py
new file mode 100644
index 000000000..90bb9ac75
--- /dev/null
+++ b/test/examples/import-recursion/cadquery_simple/cq.py
@@ -0,0 +1 @@
+from . import selectors
diff --git a/test/examples/import-recursion/cq_example.py b/test/examples/import-recursion/cq_example.py
new file mode 100644
index 000000000..00a571762
--- /dev/null
+++ b/test/examples/import-recursion/cq_example.py
@@ -0,0 +1,3 @@
+import cadquery_simple as cq
+
+cq.
diff --git a/test/test_api/test_api.py b/test/test_api/test_api.py
index 1829e30f9..51c0da3be 100644
--- a/test/test_api/test_api.py
+++ b/test/test_api/test_api.py
@@ -370,3 +370,35 @@ def test_multi_goto(Script):
     y, = script.goto(line=4)
     assert x.line == 1
     assert y.line == 2
+
+
+@pytest.mark.parametrize(
+    'code, column, expected', [
+        ('str() ', 3, 'str'),
+        ('str() ', 4, 'str'),
+        ('str() ', 5, 'str'),
+        ('str() ', 6, None),
+        ('str(    ) ', 6, None),
+        ('   1', 1, None),
+        ('str(1) ', 3, 'str'),
+        ('str(1) ', 4, 'int'),
+        ('str(1) ', 5, 'int'),
+        ('str(1) ', 6, 'str'),
+        ('str(1) ', 7, None),
+        ('str( 1) ', 4, 'str'),
+        ('str( 1) ', 5, 'int'),
+        ('str(+1) ', 4, 'str'),
+        ('str(+1) ', 5, 'int'),
+        ('str(1, 1.) ', 3, 'str'),
+        ('str(1, 1.) ', 4, 'int'),
+        ('str(1, 1.) ', 5, 'int'),
+        ('str(1, 1.) ', 6, None),
+        ('str(1, 1.) ', 7, 'float'),
+    ]
+)
+def test_infer_after_parentheses(Script, code, column, expected):
+    completions = Script(code).infer(column=column)
+    if expected is None:
+        assert completions == []
+    else:
+        assert [c.name for c in completions] == [expected]
diff --git a/test/test_api/test_classes.py b/test/test_api/test_classes.py
index 6add83f61..4a6f7323c 100644
--- a/test/test_api/test_classes.py
+++ b/test/test_api/test_classes.py
@@ -513,10 +513,14 @@ def foo(bar, baz):
 
     assert run('foo(bar').name_with_symbols == 'bar='
     assert run('foo(bar').complete == '='
+    assert run('foo(bar').get_completion_prefix_length() == 3
     assert run('foo(bar, baz').complete == '='
+    assert run('foo(bar, baz').get_completion_prefix_length() == 3
     assert run('    bar').name_with_symbols == 'bar'
     assert run('    bar').complete == ''
+    assert run('    bar').get_completion_prefix_length() == 3
     x = run('foo(bar=isins').name_with_symbols
+    assert run('foo(bar=isins').get_completion_prefix_length() == 5
     assert x == 'isinstance'
 
 
diff --git a/test/test_api/test_project.py b/test/test_api/test_project.py
index c8533618d..9ca4686ca 100644
--- a/test/test_api/test_project.py
+++ b/test/test_api/test_project.py
@@ -6,6 +6,7 @@
 from ..helpers import get_example_dir, set_cwd, root_dir, test_dir
 from jedi import Interpreter
 from jedi.api import Project, get_default_project
+from jedi.api.project import _is_potential_project, _CONTAINS_POTENTIAL_PROJECT
 
 
 def test_django_default_project(Script):
@@ -160,3 +161,21 @@ def test_complete_search(Script, string, completions, all_scopes):
     project = Project(test_dir)
     defs = project.complete_search(string, all_scopes=all_scopes)
     assert [d.complete for d in defs] == completions
+
+
+@pytest.mark.parametrize(
+    'path,expected', [
+        (Path(__file__).parents[2], True), # The path of the project
+        (Path(__file__).parents[1], False), # The path of the tests, not a project
+        (Path.home(), None)
+    ]
+)
+def test_is_potential_project(path, expected):
+
+    if expected is None:
+        try:
+            expected = _CONTAINS_POTENTIAL_PROJECT in os.listdir(path)
+        except OSError:
+            expected = False
+
+    assert _is_potential_project(path) == expected
diff --git a/test/test_inference/test_docstring.py b/test/test_inference/test_docstring.py
index 3fc54eb19..62d36683b 100644
--- a/test/test_inference/test_docstring.py
+++ b/test/test_inference/test_docstring.py
@@ -206,6 +206,24 @@ def foobar(x, y):
     assert 'capitalize' in names
     assert 'numerator' in names
 
+@pytest.mark.skipif(numpydoc_unavailable,
+                    reason='numpydoc module is unavailable')
+def test_numpydoc_parameters_set_single_value():
+    """
+    This is found in numpy  masked-array I'm not too sure what this means but should not crash
+    """
+    s = dedent('''
+    def foobar(x, y):
+        """
+        Parameters
+        ----------
+        x : {var}, optional
+        """
+        x.''')
+    names = [c.name for c in jedi.Script(s).complete()]
+    # just don't crash
+    assert names == []
+
 
 @pytest.mark.skipif(numpydoc_unavailable,
                     reason='numpydoc module is unavailable')
diff --git a/test/test_inference/test_gradual/test_conversion.py b/test/test_inference/test_gradual/test_conversion.py
index fd201aee0..c77a06b03 100644
--- a/test/test_inference/test_gradual/test_conversion.py
+++ b/test/test_inference/test_gradual/test_conversion.py
@@ -1,4 +1,5 @@
 import os
+from parso.cache import parser_cache
 
 from test.helpers import root_dir
 from jedi.api.project import Project
@@ -64,6 +65,17 @@ def test_goto_import(Script):
     assert not d.is_stub()
 
 
+def test_stub_get_line_code(Script):
+    code = 'from abc import ABC; ABC'
+    script = Script(code)
+    d, = script.goto(only_stubs=True)
+    assert d.get_line_code() == 'class ABC(metaclass=ABCMeta): ...\n'
+    del parser_cache[script._inference_state.latest_grammar._hashed][d.module_path]
+    d, = Script(path=d.module_path).goto(d.line, d.column, only_stubs=True)
+    assert d.is_stub()
+    assert d.get_line_code() == 'class ABC(metaclass=ABCMeta): ...\n'
+
+
 def test_os_stat_result(Script):
     d, = Script('import os; os.stat_result').goto()
     assert d.is_stub()
diff --git a/test/test_inference/test_imports.py b/test/test_inference/test_imports.py
index bbc337acc..0dd97dfd1 100644
--- a/test/test_inference/test_imports.py
+++ b/test/test_inference/test_imports.py
@@ -489,3 +489,9 @@ def test_relative_imports_without_path_and_setup_py(
             assert n.name == name
             assert n.type == 'module'
             assert n.line == 1
+
+
+def test_import_recursion(Script):
+    path = get_example_dir('import-recursion', "cq_example.py")
+    for c in Script(path=path).complete(3, 3):
+        c.docstring()
diff --git a/test/test_inference/test_signature.py b/test/test_inference/test_signature.py
index 500759bc5..02f119a8b 100644
--- a/test/test_inference/test_signature.py
+++ b/test/test_inference/test_signature.py
@@ -340,3 +340,20 @@ def test_overload(Script, code):
     x1, x2 = Script(code, path=os.path.join(dir_, 'foo.py')).get_signatures()
     assert x1.to_string() == 'with_overload(x: int, y: int) -> float'
     assert x2.to_string() == 'with_overload(x: str, y: list) -> float'
+
+
+def test_enum(Script):
+    script = Script('''\
+        from enum import Enum
+
+        class Planet(Enum):
+            MERCURY = (3.303e+23, 2.4397e6)
+            VENUS = (4.869e+24, 6.0518e6)
+
+            def __init__(self, mass, radius):
+                self.mass = mass  # in kilograms
+                self.radius = radius  # in meters
+
+        Planet.MERCURY''')
+    completion, = script.complete()
+    assert not completion.get_signatures()