diff --git a/.travis.yml b/.travis.yml
index 08a8ed2507b..008d4c88007 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -38,7 +38,7 @@ before_install:
   - source ./ci/travis/setup.sh
 
 install:
-  - pip install setuptools-rust pytest pytest-benchmark
+  - pip install setuptools-rust pytest pytest-benchmark tox
 
 script:
   - ./ci/travis/test.sh
diff --git a/ci/travis/test.sh b/ci/travis/test.sh
index 095ad69b779..cd4b9c5f351 100755
--- a/ci/travis/test.sh
+++ b/ci/travis/test.sh
@@ -7,7 +7,11 @@ cargo test --features $FEATURES
 
 for example in examples/*; do
   cd $example
-  python setup.py install
-  pytest -v tests
+  if [ -f tox.ini ]; then
+      tox -e py
+  else
+    pip install -e .
+    pytest -v tests
+  fi
   cd $TRAVIS_BUILD_DIR
 done
diff --git a/examples/rustapi_module/.gitignore b/examples/rustapi_module/.gitignore
new file mode 100644
index 00000000000..7a6ac170309
--- /dev/null
+++ b/examples/rustapi_module/.gitignore
@@ -0,0 +1,6 @@
+.pytest_cache
+.mypy_cache
+.hypothesis
+.tox
+
+*.py[co]
diff --git a/examples/rustapi_module/Cargo.toml b/examples/rustapi_module/Cargo.toml
new file mode 100644
index 00000000000..abff444343b
--- /dev/null
+++ b/examples/rustapi_module/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+authors = ["PyO3 Authors"]
+name = "rustapi-module"
+version = "0.1.0"
+description = "A Python wrapper for the Rust API for purposes of testing"
+
+[dependencies]
+
+[dependencies.pyo3]
+path = "../../"
+features = ["extension-module"]
+
+[lib]
+name = "rustapi_module"
+crate-type = ["cdylib"]
diff --git a/examples/rustapi_module/pyproject.toml b/examples/rustapi_module/pyproject.toml
new file mode 100644
index 00000000000..0f58585acf6
--- /dev/null
+++ b/examples/rustapi_module/pyproject.toml
@@ -0,0 +1,2 @@
+[build-system]
+requires = ["setuptools", "wheel", "setuptools_rust>=0.10.2"]
diff --git a/examples/rustapi_module/requirements-dev.txt b/examples/rustapi_module/requirements-dev.txt
new file mode 100644
index 00000000000..b1000dbbb17
--- /dev/null
+++ b/examples/rustapi_module/requirements-dev.txt
@@ -0,0 +1,3 @@
+hypothesis>=3.55
+pytest>=3.5.0
+setuptools-rust>=0.10.2
diff --git a/examples/rustapi_module/rustapi_module/__init__.py b/examples/rustapi_module/rustapi_module/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/examples/rustapi_module/setup.py b/examples/rustapi_module/setup.py
new file mode 100644
index 00000000000..0efaae03f9a
--- /dev/null
+++ b/examples/rustapi_module/setup.py
@@ -0,0 +1,56 @@
+import sys
+
+from setuptools import setup
+from setuptools.command.test import test as TestCommand
+from setuptools_rust import RustExtension
+
+
+class PyTest(TestCommand):
+    user_options = []
+
+    def run(self):
+        self.run_command("test_rust")
+
+        import subprocess
+        errno = subprocess.call(['pytest', 'tests'])
+        raise SystemExit(errno)
+
+
+def get_py_version_cfgs():
+    # For now each Cfg Py_3_X flag is interpreted as "at least 3.X"
+    version = sys.version_info[0:2]
+
+    if version[0] == 2:
+        return ['--cfg=Py_2']
+
+    py3_min = 5
+    out_cfg = []
+    for minor in range(py3_min, version[1]+1):
+        out_cfg.append('--cfg=Py_3_%d' % minor)
+
+    return out_cfg
+
+install_requires = []
+tests_require = install_requires + ['pytest', 'pytest-benchmark']
+
+setup(
+    name='rustapi-module',
+    version='0.1.0',
+    classifiers=[
+        'License :: OSI Approved :: MIT License',
+        'Development Status :: 3 - Alpha',
+        'Intended Audience :: Developers',
+        'Programming Language :: Python',
+        'Programming Language :: Rust',
+        'Operating System :: POSIX',
+        'Operating System :: MacOS :: MacOS X',
+    ],
+    packages=['rustapi_module'],
+    rust_extensions=[RustExtension('rustapi_module.datetime', 'Cargo.toml',
+                                   rustc_flags=get_py_version_cfgs())],
+    install_requires=install_requires,
+    tests_require=tests_require,
+    include_package_data=True,
+    zip_safe=False,
+    cmdclass=dict(test=PyTest)
+)
diff --git a/examples/rustapi_module/src/lib.rs b/examples/rustapi_module/src/lib.rs
new file mode 100644
index 00000000000..6c2ef34c619
--- /dev/null
+++ b/examples/rustapi_module/src/lib.rs
@@ -0,0 +1,217 @@
+#![feature(specialization)]
+
+#[macro_use]
+extern crate pyo3;
+
+use pyo3::prelude::PyDeltaAccess;
+use pyo3::prelude::PyModule;
+use pyo3::prelude::PyObject;
+use pyo3::prelude::{pyfunction, pymodinit};
+use pyo3::prelude::{PyDate, PyDateTime, PyDelta, PyTime, PyTzInfo};
+use pyo3::prelude::{PyDateAccess, PyTimeAccess};
+use pyo3::prelude::{PyDict, PyTuple};
+use pyo3::{ObjectProtocol, ToPyObject};
+use pyo3::{Py, PyResult, Python};
+
+#[pyfunction]
+fn make_date(py: Python, year: i32, month: u8, day: u8) -> PyResult<Py<PyDate>> {
+    PyDate::new(py, year, month, day)
+}
+
+#[pyfunction]
+fn get_date_tuple(py: Python, d: &PyDate) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[d.get_year(), d.get_month() as i32, d.get_day() as i32],
+    )
+}
+
+#[pyfunction]
+fn date_from_timestamp(py: Python, ts: i64) -> PyResult<Py<PyDate>> {
+    let timestamp = ts.to_object(py);
+    let args = PyTuple::new(py, &[timestamp]);
+    PyDate::from_timestamp(py, &args.to_object(py))
+}
+
+#[pyfunction]
+fn make_time(
+    py: Python,
+    hour: u8,
+    minute: u8,
+    second: u8,
+    microsecond: u32,
+    tzinfo: Option<&PyTzInfo>,
+) -> PyResult<Py<PyTime>> {
+    PyTime::new(
+        py,
+        hour,
+        minute,
+        second,
+        microsecond,
+        tzinfo.map(|o| o.to_object(py)).as_ref(),
+    )
+}
+
+#[cfg(Py_3_6)]
+#[pyfunction]
+fn time_with_fold(
+    py: Python,
+    hour: u8,
+    minute: u8,
+    second: u8,
+    microsecond: u32,
+    tzinfo: Option<&PyTzInfo>,
+    fold: bool,
+) -> PyResult<Py<PyTime>> {
+    PyTime::new_with_fold(
+        py,
+        hour,
+        minute,
+        second,
+        microsecond,
+        tzinfo.map(|o| o.to_object(py)).as_ref(),
+        fold,
+    )
+}
+
+#[pyfunction]
+fn get_time_tuple(py: Python, dt: &PyTime) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[
+            dt.get_hour() as u32,
+            dt.get_minute() as u32,
+            dt.get_second() as u32,
+            dt.get_microsecond(),
+        ],
+    )
+}
+
+#[cfg(Py_3_6)]
+#[pyfunction]
+fn get_time_tuple_fold(py: Python, dt: &PyTime) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[
+            dt.get_hour() as u32,
+            dt.get_minute() as u32,
+            dt.get_second() as u32,
+            dt.get_microsecond(),
+            dt.get_fold() as u32,
+        ],
+    )
+}
+
+#[pyfunction]
+fn make_delta(py: Python, days: i32, seconds: i32, microseconds: i32) -> PyResult<Py<PyDelta>> {
+    PyDelta::new(py, days, seconds, microseconds, true)
+}
+
+#[pyfunction]
+fn get_delta_tuple(py: Python, delta: &PyDelta) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[
+            delta.get_days(),
+            delta.get_seconds(),
+            delta.get_microseconds(),
+        ],
+    )
+}
+
+#[pyfunction]
+fn make_datetime(
+    py: Python,
+    year: i32,
+    month: u8,
+    day: u8,
+    hour: u8,
+    minute: u8,
+    second: u8,
+    microsecond: u32,
+    tzinfo: Option<&PyTzInfo>,
+) -> PyResult<Py<PyDateTime>> {
+    PyDateTime::new(
+        py,
+        year,
+        month,
+        day,
+        hour,
+        minute,
+        second,
+        microsecond,
+        tzinfo.map(|o| (o.to_object(py))).as_ref(),
+    )
+}
+
+#[pyfunction]
+fn get_datetime_tuple(py: Python, dt: &PyDateTime) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[
+            dt.get_year(),
+            dt.get_month() as i32,
+            dt.get_day() as i32,
+            dt.get_hour() as i32,
+            dt.get_minute() as i32,
+            dt.get_second() as i32,
+            dt.get_microsecond() as i32,
+        ],
+    )
+}
+
+#[cfg(Py_3_6)]
+#[pyfunction]
+fn get_datetime_tuple_fold(py: Python, dt: &PyDateTime) -> Py<PyTuple> {
+    PyTuple::new(
+        py,
+        &[
+            dt.get_year(),
+            dt.get_month() as i32,
+            dt.get_day() as i32,
+            dt.get_hour() as i32,
+            dt.get_minute() as i32,
+            dt.get_second() as i32,
+            dt.get_microsecond() as i32,
+            dt.get_fold() as i32,
+        ],
+    )
+}
+
+#[pyfunction]
+fn datetime_from_timestamp(py: Python, ts: f64, tz: Option<&PyTzInfo>) -> PyResult<Py<PyDateTime>> {
+    let timestamp: PyObject = ts.to_object(py);
+    let tzi: PyObject = match tz {
+        Some(t) => t.to_object(py),
+        None => py.None(),
+    };
+
+    let args = PyTuple::new(py, &[timestamp, tzi]);
+    let kwargs = PyDict::new(py);
+
+    PyDateTime::from_timestamp(py, &args.to_object(py), &kwargs.to_object(py))
+}
+
+#[pymodinit]
+fn datetime(_py: Python, m: &PyModule) -> PyResult<()> {
+    m.add_function(wrap_function!(make_date))?;
+    m.add_function(wrap_function!(get_date_tuple))?;
+    m.add_function(wrap_function!(date_from_timestamp))?;
+    m.add_function(wrap_function!(make_time))?;
+    m.add_function(wrap_function!(get_time_tuple))?;
+    m.add_function(wrap_function!(make_delta))?;
+    m.add_function(wrap_function!(get_delta_tuple))?;
+    m.add_function(wrap_function!(make_datetime))?;
+    m.add_function(wrap_function!(get_datetime_tuple))?;
+    m.add_function(wrap_function!(datetime_from_timestamp))?;
+
+    // Python 3.6+ functions
+    #[cfg(Py_3_6)]
+    {
+        m.add_function(wrap_function!(time_with_fold));
+        m.add_function(wrap_function!(get_time_tuple_fold));
+        m.add_function(wrap_function!(get_datetime_tuple_fold));
+    }
+
+    Ok(())
+}
diff --git a/examples/rustapi_module/tests/test_datetime.py b/examples/rustapi_module/tests/test_datetime.py
new file mode 100644
index 00000000000..ccfa6ae281e
--- /dev/null
+++ b/examples/rustapi_module/tests/test_datetime.py
@@ -0,0 +1,263 @@
+import rustapi_module.datetime as rdt
+
+import sys
+import datetime as pdt
+
+import pytest
+
+from hypothesis import given
+from hypothesis import strategies as st
+from hypothesis.strategies import dates, datetimes
+
+# Constants
+def _get_utc():
+    timezone = getattr(pdt, 'timezone', None)
+    if timezone:
+        return timezone.utc
+    else:
+        class UTC(pdt.tzinfo):
+            def utcoffset(self, dt):
+                return pdt.timedelta(0)
+
+            def dst(self, dt):
+                return pdt.timedelta(0)
+
+            def tzname(self, dt):
+                return "UTC"
+
+        return UTC()
+
+UTC = _get_utc()
+
+MAX_SECONDS = int(pdt.timedelta.max.total_seconds())
+MIN_SECONDS = int(pdt.timedelta.min.total_seconds())
+
+try:
+    MAX_DAYS = pdt.timedelta.max // pdt.timedelta(days=1)
+    MIN_DAYS = pdt.timedelta.min // pdt.timedelta(days=1)
+except Exception:
+    # Python 2 compatibility
+    MAX_DAYS = MAX_SECONDS // pdt.timedelta(days=1).total_seconds()
+    MIN_DAYS = MIN_SECONDS // pdt.timedelta(days=1).total_seconds()
+
+MAX_MICROSECONDS = int(pdt.timedelta.max.total_seconds() * 1e6)
+MIN_MICROSECONDS = int(pdt.timedelta.min.total_seconds() * 1e6)
+
+HAS_FOLD = getattr(pdt.datetime, 'fold', False)
+
+
+# Helper functions
+get_timestamp = getattr(pdt.datetime, 'timestamp', None)
+if get_timestamp is None:
+    def get_timestamp(dt):
+        # Python 2 compatibility
+        return (dt - pdt.datetime(1970, 1, 1)).total_seconds()
+
+
+xfail_date_bounds = pytest.mark.xfail(sys.version_info < (3, 6),
+    reason="Date bounds were not checked in the C constructor prior to version 3.6")
+
+# Tests
+def test_date():
+    assert rdt.make_date(2017, 9, 1) == pdt.date(2017, 9, 1)
+
+
+@given(d=st.dates())
+def test_date_accessors(d):
+    act = rdt.get_date_tuple(d)
+    exp = (d.year, d.month, d.day)
+
+    assert act == exp
+
+
+@xfail_date_bounds
+def test_invalid_date_fails():
+    with pytest.raises(ValueError):
+        rdt.make_date(2017, 2, 30)
+
+
+@given(d=dates())
+def test_date_from_timestamp(d):
+    ts = get_timestamp(pdt.datetime.combine(d, pdt.time(0)))
+    assert rdt.date_from_timestamp(int(ts)) == pdt.date.fromtimestamp(ts)
+
+
+@pytest.mark.parametrize('args, kwargs', [
+    ((0, 0, 0, 0, None), {}),
+    ((1, 12, 14, 124731), {}),
+    ((1, 12, 14, 124731), {'tzinfo': UTC}),
+])
+def test_time(args, kwargs):
+    act = rdt.make_time(*args, **kwargs)
+    exp = pdt.time(*args, **kwargs)
+
+    assert act == exp
+    assert act.tzinfo is exp.tzinfo
+
+
+@given(t=st.times())
+def test_time(t):
+    act = rdt.get_time_tuple(t)
+    exp = (t.hour, t.minute, t.second, t.microsecond)
+
+    assert act == exp
+
+
+@pytest.mark.skipif(not HAS_FOLD, reason="Feature not available before 3.6")
+@given(t=st.times())
+def test_time_fold(t):
+    t_nofold = t.replace(fold=0)
+    t_fold = t.replace(fold=1)
+
+    for t in (t_nofold, t_fold):
+        act = rdt.get_time_tuple_fold(t)
+        exp = (t.hour, t.minute, t.second, t.microsecond, t.fold)
+
+        assert act == exp
+
+
+@pytest.mark.skipif(not HAS_FOLD, reason="Feature not available before 3.6")
+@pytest.mark.parametrize('fold', [False, True])
+def test_time_fold(fold):
+    t = rdt.time_with_fold(0, 0, 0, 0, None, fold)
+    assert t.fold == fold
+
+
+@pytest.mark.xfail
+@pytest.mark.parametrize('args', [
+    (-1, 0, 0, 0),
+    (0, -1, 0, 0),
+    (0, 0, -1, 0),
+    (0, 0, 0, -1),
+])
+def test_invalid_time_fails_xfail(args):
+    with pytest.raises(ValueError):
+        rdt.make_time(*args)
+
+
+@xfail_date_bounds
+@pytest.mark.parametrize('args', [
+    (24, 0, 0, 0),
+    (25, 0, 0, 0),
+    (0, 60, 0, 0),
+    (0, 61, 0, 0),
+    (0, 0, 60, 0),
+    (0, 0, 61, 0),
+    (0, 0, 0, 1000000)
+])
+def test_invalid_time_fails(args):
+    with pytest.raises(ValueError):
+        rdt.make_time(*args)
+
+
+@pytest.mark.parametrize('args', [
+    ('0', 0, 0, 0),
+    (0, '0', 0, 0),
+    (0, 0, '0', 0),
+    (0, 0, 0, '0'),
+    (0, 0, 0, 0, 'UTC')
+])
+def test_time_typeerror(args):
+    with pytest.raises(TypeError):
+        rdt.make_time(*args)
+
+
+@pytest.mark.parametrize('args, kwargs', [
+    ((2017, 9, 1, 12, 45, 30, 0), {}),
+    ((2017, 9, 1, 12, 45, 30, 0), {'tzinfo': UTC}),
+])
+def test_datetime(args, kwargs):
+    act = rdt.make_datetime(*args, **kwargs)
+    exp = pdt.datetime(*args, **kwargs)
+
+    assert act == exp
+    assert act.tzinfo is exp.tzinfo
+
+
+@given(dt=st.datetimes())
+def test_datetime_tuple(dt):
+    act = rdt.get_datetime_tuple(dt)
+    exp = dt.timetuple()[0:6] + (dt.microsecond, )
+
+    assert act == exp
+
+
+@pytest.mark.skipif(not HAS_FOLD, reason="Feature not available before 3.6")
+@given(dt=st.datetimes())
+def test_datetime_tuple_fold(dt):
+    dt_fold = dt.replace(fold=1)
+    dt_nofold = dt.replace(fold=0)
+
+    for dt in (dt_fold, dt_nofold):
+        act = rdt.get_datetime_tuple_fold(dt)
+        exp = dt.timetuple()[0:6] + (dt.microsecond, dt.fold)
+
+        assert act == exp
+
+
+@xfail_date_bounds
+def test_invalid_datetime_fails():
+    with pytest.raises(ValueError):
+        rdt.make_datetime(2011, 1, 42, 0, 0, 0, 0)
+
+
+def test_datetime_typeerror():
+    with pytest.raises(TypeError):
+        rdt.make_datetime('2011', 1, 1, 0, 0, 0, 0)
+
+
+@given(dt=datetimes())
+def test_datetime_from_timestamp(dt):
+    ts = get_timestamp(dt)
+    assert rdt.datetime_from_timestamp(ts) == pdt.datetime.fromtimestamp(ts)
+
+
+def test_datetime_from_timestamp_tzinfo():
+    d1 = rdt.datetime_from_timestamp(0, tz=UTC)
+    d2 = rdt.datetime_from_timestamp(0, tz=UTC)
+
+    assert d1 == d2
+    assert d1.tzinfo is d2.tzinfo
+
+
+@pytest.mark.parametrize('args', [
+    (0, 0, 0),
+    (1, 0, 0),
+    (-1, 0, 0),
+    (0, 1, 0),
+    (0, -1, 0),
+    (1, -1, 0),
+    (-1, 1, 0),
+    (0, 0, 123456),
+    (0, 0, -123456),
+])
+def test_delta(args):
+    act = pdt.timedelta(*args)
+    exp = rdt.make_delta(*args)
+
+    assert act == exp
+
+
+@given(td=st.timedeltas())
+def test_delta_accessors(td):
+    act = rdt.get_delta_tuple(td)
+    exp = (td.days, td.seconds, td.microseconds)
+
+    assert act == exp
+
+
+@pytest.mark.parametrize('args,err_type', [
+    ((MAX_DAYS + 1, 0, 0), OverflowError),
+    ((MIN_DAYS - 1, 0, 0), OverflowError),
+    ((0, MAX_SECONDS + 1, 0), OverflowError),
+    ((0, MIN_SECONDS - 1, 0), OverflowError),
+    ((0, 0, MAX_MICROSECONDS + 1), OverflowError),
+    ((0, 0, MIN_MICROSECONDS - 1), OverflowError),
+    (('0', 0, 0), TypeError),
+    ((0, '0', 0), TypeError),
+    ((0, 0, '0'), TypeError),
+])
+def test_delta_err(args, err_type):
+    with pytest.raises(err_type):
+        rdt.make_delta(*args)
+
diff --git a/examples/rustapi_module/tox.ini b/examples/rustapi_module/tox.ini
new file mode 100644
index 00000000000..11e866b5d0d
--- /dev/null
+++ b/examples/rustapi_module/tox.ini
@@ -0,0 +1,14 @@
+[tox]
+envlist = py27,
+          py35,
+          py36,
+          py37,
+minversion = 2.9.0
+skip_missing_interpreters = true
+
+[testenv]
+description = Run the unit tests under {basepython}
+deps = -rrequirements-dev.txt
+usedevelop = True
+commands = pip install -e .
+           pytest
diff --git a/pyo3-derive-backend/src/py_class.rs b/pyo3-derive-backend/src/py_class.rs
index da09a50930d..cab748fc197 100644
--- a/pyo3-derive-backend/src/py_class.rs
+++ b/pyo3-derive-backend/src/py_class.rs
@@ -86,7 +86,7 @@ fn impl_class(
     let extra = if let Some(token) = token {
         Some(quote! {
             impl ::pyo3::PyObjectWithToken for #cls {
-                #[inline(always)]
+                #[inline]
                 fn py<'p>(&'p self) -> ::pyo3::Python<'p> {
                     self.#token.py()
                 }
@@ -243,7 +243,7 @@ fn impl_class(
         }
 
         impl ::pyo3::typeob::PyTypeObject for #cls {
-            #[inline(always)]
+            #[inline]
             fn init_type() {
                 static START: std::sync::Once = std::sync::ONCE_INIT;
                 START.call_once(|| {
diff --git a/src/err.rs b/src/err.rs
index 8023f108eef..8012ac8a014 100644
--- a/src/err.rs
+++ b/src/err.rs
@@ -90,7 +90,7 @@ macro_rules! py_exception {
         }
 
         impl $crate::typeob::PyTypeObject for $name {
-            #[inline(always)]
+            #[inline]
             fn init_type() {
                 let _ = $name::type_object();
             }
diff --git a/src/ffi/datetime.rs b/src/ffi/datetime.rs
new file mode 100644
index 00000000000..6cc01762d97
--- /dev/null
+++ b/src/ffi/datetime.rs
@@ -0,0 +1,410 @@
+#![cfg_attr(feature="cargo-clippy", allow(type_complexity))]
+
+use ffi::PyCapsule_Import;
+use ffi::Py_hash_t;
+use ffi::{PyObject, PyTypeObject};
+use ffi::{PyObject_TypeCheck, Py_TYPE};
+use std::ffi::CString;
+use std::ops::Deref;
+use std::os::raw::{c_char, c_int, c_uchar};
+use std::ptr;
+use std::sync::Once;
+
+#[cfg_attr(windows, link(name = "pythonXY"))]
+extern "C" {
+    pub static mut PyDateTime_DateType: PyTypeObject;
+    pub static mut PyDateTime_TimeType: PyTypeObject;
+    pub static mut PyDateTime_DateTimeType: PyTypeObject;
+
+    pub static mut PyDateTime_DeltaType: PyTypeObject;
+    pub static mut PyDateTime_TZInfoType: PyTypeObject;
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct PyDateTime_CAPI {
+    pub DateType: *mut PyTypeObject,
+    pub DateTimeType: *mut PyTypeObject,
+    pub TimeType: *mut PyTypeObject,
+    pub DeltaType: *mut PyTypeObject,
+    pub TZInfoType: *mut PyTypeObject,
+    #[cfg(Py_3_7)]
+    pub TimeZone_UTC: *mut PyObject,
+
+    pub Date_FromDate:
+        unsafe extern "C" fn(year: c_int, month: c_int, day: c_int, cls: *mut PyTypeObject)
+            -> *mut PyObject,
+    pub DateTime_FromDateAndTime: unsafe extern "C" fn(
+        year: c_int,
+        month: c_int,
+        day: c_int,
+        hour: c_int,
+        minute: c_int,
+        second: c_int,
+        microsecond: c_int,
+        tzinfo: *mut PyObject,
+        cls: *mut PyTypeObject,
+    ) -> *mut PyObject,
+    pub Time_FromTime: unsafe extern "C" fn(
+        hour: c_int,
+        minute: c_int,
+        second: c_int,
+        microsecond: c_int,
+        tzinfo: *mut PyObject,
+        cls: *mut PyTypeObject,
+    ) -> *mut PyObject,
+    pub Delta_FromDelta: unsafe extern "C" fn(
+        days: c_int,
+        seconds: c_int,
+        microseconds: c_int,
+        normalize: c_int,
+        cls: *mut PyTypeObject,
+    ) -> *mut PyObject,
+    #[cfg(Py_3_7)]
+    pub TimeZone_FromTimeZone:
+        unsafe extern "C" fn(offset: *mut PyObject, name: *mut PyObject) -> *mut PyObject,
+    pub DateTime_FromTimestamp:
+        unsafe extern "C" fn(cls: *mut PyTypeObject, args: *mut PyObject, kwargs: *mut PyObject)
+            -> *mut PyObject,
+    pub Date_FromTimestamp:
+        unsafe extern "C" fn(cls: *mut PyTypeObject, args: *mut PyObject) -> *mut PyObject,
+    #[cfg(Py_3_6)]
+    pub DateTime_FromDateAndTimeAndFold: unsafe extern "C" fn(
+        year: c_int,
+        month: c_int,
+        day: c_int,
+        hour: c_int,
+        minute: c_int,
+        second: c_int,
+        microsecond: c_int,
+        tzinfo: *mut PyObject,
+        fold: c_int,
+        cls: *mut PyTypeObject,
+    ) -> *mut PyObject,
+    #[cfg(Py_3_6)]
+    pub Time_FromTimeAndFold: unsafe extern "C" fn(
+        hour: c_int,
+        minute: c_int,
+        second: c_int,
+        microsecond: c_int,
+        tzinfo: *mut PyObject,
+        fold: c_int,
+        cls: *mut PyTypeObject,
+    ) -> *mut PyObject,
+}
+
+// Type struct wrappers
+
+const _PyDateTime_DATE_DATASIZE: usize = 4;
+const _PyDateTime_TIME_DATASIZE: usize = 6;
+const _PyDateTime_DATETIME_DATASIZE: usize = 10;
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct PyDateTime_Date {
+    pub ob_base: PyObject,
+    pub hashcode: Py_hash_t,
+    pub hastzinfo: c_char,
+    pub data: [c_uchar; _PyDateTime_DATE_DATASIZE],
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct PyDateTime_Time {
+    pub ob_base: PyObject,
+    pub hashcode: Py_hash_t,
+    pub hastzinfo: c_char,
+    pub data: [c_uchar; _PyDateTime_TIME_DATASIZE],
+    #[cfg(Py_3_6)]
+    pub fold: c_uchar,
+    pub tzinfo: *mut PyObject,
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct PyDateTime_DateTime {
+    pub ob_base: PyObject,
+    pub hashcode: Py_hash_t,
+    pub hastzinfo: c_char,
+    pub data: [c_uchar; _PyDateTime_DATETIME_DATASIZE],
+    #[cfg(Py_3_6)]
+    pub fold: c_uchar,
+    pub tzinfo: *mut PyObject,
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct PyDateTime_Delta {
+    pub ob_base: PyObject,
+    pub hashcode: Py_hash_t,
+    pub days: c_int,
+    pub seconds: c_int,
+    pub microseconds: c_int,
+}
+
+// C API Capsule
+// Note: This is "roll-your-own" lazy-static implementation is necessary because
+// of the interaction between the call_once locks and the GIL. It turns out that
+// calling PyCapsule_Import releases and re-acquires the GIL during the import,
+// so if you have two threads attempting to use the PyDateTimeAPI singleton
+// under the GIL, it causes a deadlock; what happens is:
+//
+// Thread 1 acquires GIL
+// Thread 1 acquires the call_once lock
+// Thread 1 calls PyCapsule_Import, thus releasing the GIL
+// Thread 2 acquires the GIL
+// Thread 2 blocks waiting for the call_once lock
+// Thread 1 blocks waiting for the GIL
+//
+// However, Python's import mechanism acquires a module-specific lock around
+// each import call, so all call importing datetime will return the same
+// object, making the call_once lock superfluous. As such, we can weaken
+// the guarantees of the cache, such that PyDateTime_IMPORT can be called
+// until __PY_DATETIME_API_UNSAFE_CACHE is populated, which will happen exactly
+// one time. So long as PyDateTime_IMPORT has no side effects (it should not),
+// this will be at most a slight waste of resources.
+static PY_DATETIME_API_ONCE: Once = Once::new();
+static mut PY_DATETIME_API_UNSAFE_CACHE: *const PyDateTime_CAPI = ptr::null();
+
+pub struct PyDateTimeAPI {
+    __private_field: (),
+}
+pub static PyDateTimeAPI: PyDateTimeAPI = PyDateTimeAPI {
+    __private_field: (),
+};
+
+impl Deref for PyDateTimeAPI {
+    type Target = PyDateTime_CAPI;
+
+    fn deref(&self) -> &'static PyDateTime_CAPI {
+        unsafe {
+            if !PY_DATETIME_API_UNSAFE_CACHE.is_null() {
+                &(*PY_DATETIME_API_UNSAFE_CACHE)
+            } else {
+                PyDateTime_IMPORT()
+            }
+        }
+    }
+}
+
+#[inline]
+pub unsafe fn PyDateTime_IMPORT() -> &'static PyDateTime_CAPI {
+    // PyDateTime_CAPSULE_NAME is a macro in C
+    let PyDateTime_CAPSULE_NAME = CString::new("datetime.datetime_CAPI").unwrap();
+
+    let capsule = PyCapsule_Import(PyDateTime_CAPSULE_NAME.as_ptr(), 1) as *const PyDateTime_CAPI;
+
+    PY_DATETIME_API_ONCE.call_once(move || {
+        PY_DATETIME_API_UNSAFE_CACHE = capsule;
+    });
+
+    &(*PY_DATETIME_API_UNSAFE_CACHE)
+}
+
+//
+// Type Check macros
+//
+#[inline]
+pub unsafe fn PyDate_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, PyDateTimeAPI.DateType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyDate_CheckExact(op: *mut PyObject) -> c_int {
+    (Py_TYPE(op) == PyDateTimeAPI.DateType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyDateTime_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, PyDateTimeAPI.DateTimeType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyDateTime_CheckExact(op: *mut PyObject) -> c_int {
+    (Py_TYPE(op) == PyDateTimeAPI.DateTimeType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyTime_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, PyDateTimeAPI.TimeType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyTime_CheckExact(op: *mut PyObject) -> c_int {
+    (Py_TYPE(op) == PyDateTimeAPI.TimeType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyDelta_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, PyDateTimeAPI.DeltaType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyDelta_CheckExact(op: *mut PyObject) -> c_int {
+    (Py_TYPE(op) == PyDateTimeAPI.DeltaType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyTZInfo_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, PyDateTimeAPI.TZInfoType) as c_int
+}
+
+#[inline]
+pub unsafe fn PyTZInfo_CheckExact(op: *mut PyObject) -> c_int {
+    (Py_TYPE(op) == PyDateTimeAPI.TZInfoType) as c_int
+}
+
+//
+// Accessor functions
+//
+macro_rules! _access_field {
+    ($obj:expr, $type: ident, $field:tt) => {
+        (*($obj as *mut $type)).$field
+    };
+}
+
+// Accessor functions for PyDateTime_Date and PyDateTime_DateTime
+#[inline]
+pub unsafe fn PyDateTime_GET_YEAR(o: *mut PyObject) -> c_int {
+    // This should work for Date or DateTime
+    let d = *(o as *mut PyDateTime_Date);
+    (c_int::from(d.data[0]) << 8 | c_int::from(d.data[1]))
+}
+
+#[inline]
+pub unsafe fn PyDateTime_GET_MONTH(o: *mut PyObject) -> c_int {
+    let d = *(o as *mut PyDateTime_Date);
+    c_int::from(d.data[2])
+}
+
+#[inline]
+pub unsafe fn PyDateTime_GET_DAY(o: *mut PyObject) -> c_int {
+    let d = *(o as *mut PyDateTime_Date);
+    c_int::from(d.data[3])
+}
+
+// Accessor macros for times
+macro_rules! _PyDateTime_GET_HOUR {
+    ($o: expr, $offset:expr) => {
+        c_int::from((*$o).data[$offset + 0])
+    };
+}
+
+macro_rules! _PyDateTime_GET_MINUTE {
+    ($o: expr, $offset:expr) => {
+        c_int::from((*$o).data[$offset + 1])
+    };
+}
+
+macro_rules! _PyDateTime_GET_SECOND {
+    ($o: expr, $offset:expr) => {
+        c_int::from((*$o).data[$offset + 2])
+    };
+}
+
+macro_rules! _PyDateTime_GET_MICROSECOND {
+    ($o: expr, $offset:expr) => {
+        (c_int::from((*$o).data[$offset + 3]) << 16)
+            | (c_int::from((*$o).data[$offset + 4]) << 8)
+            | (c_int::from((*$o).data[$offset + 5]))
+    };
+}
+
+#[cfg(Py_3_6)]
+macro_rules! _PyDateTime_GET_FOLD {
+    ($o: expr) => {
+        (*$o).fold
+    };
+}
+
+macro_rules! _PyDateTime_GET_TZINFO {
+    ($o: expr) => {
+        (*$o).tzinfo
+    };
+}
+
+// Accessor functions for DateTime
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_HOUR(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_HOUR!((o as *mut PyDateTime_DateTime), _PyDateTime_DATE_DATASIZE)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_MINUTE(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_MINUTE!((o as *mut PyDateTime_DateTime), _PyDateTime_DATE_DATASIZE)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_SECOND(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_SECOND!((o as *mut PyDateTime_DateTime), _PyDateTime_DATE_DATASIZE)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_MICROSECOND(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_MICROSECOND!((o as *mut PyDateTime_DateTime), _PyDateTime_DATE_DATASIZE)
+}
+
+#[cfg(Py_3_6)]
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_FOLD(o: *mut PyObject) -> c_uchar {
+    _PyDateTime_GET_FOLD!(o as *mut PyDateTime_DateTime)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DATE_GET_TZINFO(o: *mut PyObject) -> *mut PyObject {
+    _PyDateTime_GET_TZINFO!(o as *mut PyDateTime_DateTime)
+}
+
+// Accessor functions for Time
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_HOUR(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_HOUR!((o as *mut PyDateTime_Time), 0)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_MINUTE(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_MINUTE!((o as *mut PyDateTime_Time), 0)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_SECOND(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_SECOND!((o as *mut PyDateTime_Time), 0)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_MICROSECOND(o: *mut PyObject) -> c_int {
+    _PyDateTime_GET_MICROSECOND!((o as *mut PyDateTime_Time), 0)
+}
+
+#[cfg(Py_3_6)]
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_FOLD(o: *mut PyObject) -> c_uchar {
+    _PyDateTime_GET_FOLD!(o as *mut PyDateTime_Time)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_TIME_GET_TZINFO(o: *mut PyObject) -> *mut PyObject {
+    _PyDateTime_GET_TZINFO!(o as *mut PyDateTime_Time)
+}
+
+// Accessor functions for PyDateTime_Delta
+macro_rules! _access_delta_field {
+    ($obj:expr, $field:tt) => {
+        _access_field!($obj, PyDateTime_Delta, $field)
+    };
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DELTA_GET_DAYS(o: *mut PyObject) -> c_int {
+    _access_delta_field!(o, days)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DELTA_GET_SECONDS(o: *mut PyObject) -> c_int {
+    _access_delta_field!(o, seconds)
+}
+
+#[inline]
+pub unsafe fn PyDateTime_DELTA_GET_MICROSECONDS(o: *mut PyObject) -> c_int {
+    _access_delta_field!(o, microseconds)
+}
diff --git a/src/ffi/mod.rs b/src/ffi/mod.rs
new file mode 100644
index 00000000000..346857f7369
--- /dev/null
+++ b/src/ffi/mod.rs
@@ -0,0 +1,11 @@
+#![allow(non_camel_case_types, non_upper_case_globals, non_snake_case)]
+
+#[cfg(not(Py_3))]
+pub use ffi2::*;
+
+#[cfg(Py_3)]
+pub use ffi3::*;
+
+pub use self::datetime::*;
+
+pub(crate) mod datetime;
diff --git a/src/ffi2/boolobject.rs b/src/ffi2/boolobject.rs
index 0248736f5e0..2cb7553fc03 100644
--- a/src/ffi2/boolobject.rs
+++ b/src/ffi2/boolobject.rs
@@ -12,18 +12,18 @@ extern "C" {
     pub fn PyBool_FromLong(arg1: c_long) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBool_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyBool_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_False() -> *mut PyObject {
     &mut _Py_ZeroStruct as *mut PyBoolObject as *mut PyObject
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_True() -> *mut PyObject {
     &mut _Py_TrueStruct as *mut PyBoolObject as *mut PyObject
 }
diff --git a/src/ffi2/bufferobject.rs b/src/ffi2/bufferobject.rs
index 7af2feecbf5..7cc5a96bfb3 100644
--- a/src/ffi2/bufferobject.rs
+++ b/src/ffi2/bufferobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     pub static mut PyBuffer_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBuffer_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyBuffer_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/bytearrayobject.rs b/src/ffi2/bytearrayobject.rs
index 5dcd64b21f8..a86203b2027 100644
--- a/src/ffi2/bytearrayobject.rs
+++ b/src/ffi2/bytearrayobject.rs
@@ -42,7 +42,7 @@ extern "C" {
     pub fn PyByteArray_Resize(bytearray: *mut PyObject, len: Py_ssize_t) -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyByteArray_AS_STRING(o: *mut PyObject) -> *mut c_char {
     PyByteArray_AsString(o)
     // #define PyByteArray_AS_STRING(self) \
@@ -50,7 +50,7 @@ pub unsafe fn PyByteArray_AS_STRING(o: *mut PyObject) -> *mut c_char {
     //    Py_SIZE(self) ? ((PyByteArrayObject *)(self))->ob_bytes : _PyByteArray_empty_string)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyByteArray_GET_SIZE(o: *mut PyObject) -> Py_ssize_t {
     // #define PyByteArray_GET_SIZE(self)  (assert(PyByteArray_Check(self)),Py_SIZE(self))
     PyByteArray_Size(o)
diff --git a/src/ffi2/cellobject.rs b/src/ffi2/cellobject.rs
index 486f0bae914..a74c3298c01 100644
--- a/src/ffi2/cellobject.rs
+++ b/src/ffi2/cellobject.rs
@@ -19,7 +19,7 @@ extern "C" {
     pub static mut PyCell_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCell_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCell_Type) as c_int
 }
@@ -31,12 +31,12 @@ extern "C" {
     pub fn PyCell_Set(op: *mut PyObject, obj: *mut PyObject) -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCell_GET(op: *mut PyObject) -> *mut PyObject {
     (*(op as *mut PyCellObject)).ob_ref
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCell_SET(op: *mut PyObject, obj: *mut PyObject) {
     (*(op as *mut PyCellObject)).ob_ref = obj;
 }
diff --git a/src/ffi2/classobject.rs b/src/ffi2/classobject.rs
index cf4132bcbeb..9238437144b 100644
--- a/src/ffi2/classobject.rs
+++ b/src/ffi2/classobject.rs
@@ -56,19 +56,19 @@ extern "C" {
     pub static mut PyMethod_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyClass_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyClass_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyInstance_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyInstance_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMethod_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyMethod_Type;
     (Py_TYPE(op) == u) as c_int
@@ -100,17 +100,17 @@ extern "C" {
     pub fn PyMethod_ClearFreeList() -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMethod_GET_FUNCTION(meth: *mut PyObject) -> *mut PyObject {
     (*(meth as *mut PyMethodObject)).im_func
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMethod_GET_SELF(meth: *mut PyObject) -> *mut PyObject {
     (*(meth as *mut PyMethodObject)).im_self
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMethod_GET_CLASS(meth: *mut PyObject) -> *mut PyObject {
     (*(meth as *mut PyMethodObject)).im_class
 }
diff --git a/src/ffi2/cobject.rs b/src/ffi2/cobject.rs
index 8c1ab3cde91..60f7d55a3cc 100644
--- a/src/ffi2/cobject.rs
+++ b/src/ffi2/cobject.rs
@@ -6,7 +6,7 @@ extern "C" {
     pub static mut PyCObject_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCObject_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCObject_Type) as c_int
 }
diff --git a/src/ffi2/code.rs b/src/ffi2/code.rs
index 80c5be196f2..baea6be3101 100644
--- a/src/ffi2/code.rs
+++ b/src/ffi2/code.rs
@@ -88,7 +88,7 @@ extern "C" {
     ) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCode_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCode_Type) as c_int
 }
diff --git a/src/ffi2/complexobject.rs b/src/ffi2/complexobject.rs
index 48a9b032842..f650c4de28b 100644
--- a/src/ffi2/complexobject.rs
+++ b/src/ffi2/complexobject.rs
@@ -37,12 +37,12 @@ extern "C" {
     pub static mut PyComplex_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyComplex_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyComplex_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyComplex_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyComplex_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/descrobject.rs b/src/ffi2/descrobject.rs
index 5c92cca527e..c2a6c3ee5a6 100644
--- a/src/ffi2/descrobject.rs
+++ b/src/ffi2/descrobject.rs
@@ -86,7 +86,7 @@ extern "C" {
     ) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDescr_IsData(d: *mut PyObject) -> c_int {
     (*Py_TYPE(d)).tp_descr_set.is_some() as c_int
 }
diff --git a/src/ffi2/dictobject.rs b/src/ffi2/dictobject.rs
index ec043bdce34..036b05c6510 100644
--- a/src/ffi2/dictobject.rs
+++ b/src/ffi2/dictobject.rs
@@ -15,12 +15,12 @@ extern "C" {
     pub static mut PyDictValues_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDict_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_DICT_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDict_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyDict_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/fileobject.rs b/src/ffi2/fileobject.rs
index 591d87e60c1..cfe881f3d2e 100644
--- a/src/ffi2/fileobject.rs
+++ b/src/ffi2/fileobject.rs
@@ -7,12 +7,12 @@ extern "C" {
     pub static mut PyFile_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFile_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyFile_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFile_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyFile_Type) as c_int
 }
diff --git a/src/ffi2/floatobject.rs b/src/ffi2/floatobject.rs
index efc96e20f65..a07c65e6816 100644
--- a/src/ffi2/floatobject.rs
+++ b/src/ffi2/floatobject.rs
@@ -19,12 +19,12 @@ extern "C" {
     pub static mut PyFloat_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFloat_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyFloat_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFloat_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyFloat_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/funcobject.rs b/src/ffi2/funcobject.rs
index 36ed08d1153..ce0c1b44a5e 100644
--- a/src/ffi2/funcobject.rs
+++ b/src/ffi2/funcobject.rs
@@ -6,7 +6,7 @@ extern "C" {
     pub static mut PyFunction_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFunction_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyFunction_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/genobject.rs b/src/ffi2/genobject.rs
index 43c3c197b39..82004d7b82e 100644
--- a/src/ffi2/genobject.rs
+++ b/src/ffi2/genobject.rs
@@ -23,12 +23,12 @@ extern "C" {
     pub static mut PyGen_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyGen_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyGen_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyGen_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyGen_Type) as c_int
 }
diff --git a/src/ffi2/intobject.rs b/src/ffi2/intobject.rs
index 254611328f4..921f8d37893 100644
--- a/src/ffi2/intobject.rs
+++ b/src/ffi2/intobject.rs
@@ -20,12 +20,12 @@ extern "C" {
     pub static mut PyInt_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyInt_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_INT_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyInt_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyInt_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/iterobject.rs b/src/ffi2/iterobject.rs
index 7f39f445723..ee9e927a0df 100644
--- a/src/ffi2/iterobject.rs
+++ b/src/ffi2/iterobject.rs
@@ -10,12 +10,12 @@ extern "C" {
     pub fn PyCallIter_New(arg1: *mut PyObject, arg2: *mut PyObject) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PySeqIter_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PySeqIter_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCallIter_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCallIter_Type) as c_int
 }
diff --git a/src/ffi2/listobject.rs b/src/ffi2/listobject.rs
index 6600aeb798c..eefa4569060 100644
--- a/src/ffi2/listobject.rs
+++ b/src/ffi2/listobject.rs
@@ -21,30 +21,30 @@ extern "C" {
     pub static mut PyList_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_LIST_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyList_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
 // Macro, trading safety for speed
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObject {
     *(*(op as *mut PyListObject)).ob_item.offset(i as isize)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_GET_SIZE(op: *mut PyObject) -> Py_ssize_t {
     Py_SIZE(op)
 }
 
 /// Macro, *only* to be used to fill in brand new lists
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_SET_ITEM(op: *mut PyObject, i: Py_ssize_t, v: *mut PyObject) {
     *(*(op as *mut PyListObject)).ob_item.offset(i as isize) = v;
 }
diff --git a/src/ffi2/longobject.rs b/src/ffi2/longobject.rs
index 8dd4a234aaa..c2cf0a4262b 100644
--- a/src/ffi2/longobject.rs
+++ b/src/ffi2/longobject.rs
@@ -12,12 +12,12 @@ extern "C" {
     pub static mut PyLong_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyLong_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_LONG_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyLong_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyLong_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/memoryobject.rs b/src/ffi2/memoryobject.rs
index 80dddcf46f9..667e0ac8b47 100644
--- a/src/ffi2/memoryobject.rs
+++ b/src/ffi2/memoryobject.rs
@@ -7,18 +7,18 @@ extern "C" {
     pub static mut PyMemoryView_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMemoryView_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyMemoryView_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMemoryView_GET_BUFFER(op: *mut PyObject) -> *mut Py_buffer {
     &mut (*(op as *mut PyMemoryViewObject)).view
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMemoryView_GET_BASE(op: *mut PyObject) -> *mut PyObject {
     (*(op as *mut PyMemoryViewObject)).view.obj
 }
diff --git a/src/ffi2/methodobject.rs b/src/ffi2/methodobject.rs
index 64912efa3a0..973849ff650 100644
--- a/src/ffi2/methodobject.rs
+++ b/src/ffi2/methodobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     pub static mut PyCFunction_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCFunction_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyCFunction_Type;
     (Py_TYPE(op) == u) as c_int
@@ -119,7 +119,7 @@ extern "C" {
     pub fn PyCFunction_ClearFreeList() -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCFunction_New(ml: *mut PyMethodDef, slf: *mut PyObject) -> *mut PyObject {
     PyCFunction_NewEx(ml, slf, ptr::null_mut())
 }
diff --git a/src/ffi2/mod.rs b/src/ffi2/mod.rs
index 29a160a73ef..14b6a75dad9 100644
--- a/src/ffi2/mod.rs
+++ b/src/ffi2/mod.rs
@@ -132,13 +132,13 @@ pub const Py_file_input: c_int = 257;
 pub const Py_eval_input: c_int = 258;
 
 #[cfg(not(py_sys_config = "Py_USING_UNICODE"))]
-#[inline(always)]
+#[inline]
 pub fn PyUnicode_Check(op: *mut PyObject) -> libc::c_int {
     0
 }
 
 #[cfg(not(py_sys_config = "Py_USING_UNICODE"))]
-#[inline(always)]
+#[inline]
 pub fn PyUnicode_CheckExact(op: *mut PyObject) -> libc::c_int {
     0
 }
diff --git a/src/ffi2/modsupport.rs b/src/ffi2/modsupport.rs
index ba66fead5ae..b915d4ca7dc 100644
--- a/src/ffi2/modsupport.rs
+++ b/src/ffi2/modsupport.rs
@@ -95,7 +95,7 @@ pub const PYTHON_API_VERSION: c_int = 1013;
     target_pointer_width = "64",
     not(py_sys_config = "Py_TRACE_REFS")
 ))]
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_InitModule4(
     name: *const c_char,
     methods: *mut PyMethodDef,
@@ -107,7 +107,7 @@ pub unsafe fn Py_InitModule4(
 }
 
 #[cfg(all(target_pointer_width = "64", py_sys_config = "Py_TRACE_REFS"))]
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_InitModule4(
     name: *const c_char,
     methods: *mut PyMethodDef,
@@ -122,7 +122,7 @@ pub unsafe fn Py_InitModule4(
     not(target_pointer_width = "64"),
     py_sys_config = "Py_TRACE_REFS"
 ))]
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_InitModule4(
     name: *const c_char,
     methods: *mut PyMethodDef,
@@ -133,7 +133,7 @@ pub unsafe fn Py_InitModule4(
     Py_InitModule4TraceRefs(name, methods, doc, _self, apiver)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_InitModule(name: *const c_char, methods: *mut PyMethodDef) -> *mut PyObject {
     Py_InitModule4(
         name,
@@ -144,7 +144,7 @@ pub unsafe fn Py_InitModule(name: *const c_char, methods: *mut PyMethodDef) -> *
     )
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_InitModule3(
     name: *const c_char,
     methods: *mut PyMethodDef,
diff --git a/src/ffi2/moduleobject.rs b/src/ffi2/moduleobject.rs
index 52546b185de..fc6c3959434 100644
--- a/src/ffi2/moduleobject.rs
+++ b/src/ffi2/moduleobject.rs
@@ -8,12 +8,12 @@ extern "C" {
     pub static mut PyModule_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyModule_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyModule_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyModule_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyModule_Type) as c_int
 }
diff --git a/src/ffi2/object.rs b/src/ffi2/object.rs
index f12d4cb9fac..c9f88079bb4 100644
--- a/src/ffi2/object.rs
+++ b/src/ffi2/object.rs
@@ -6,7 +6,7 @@ use std::os::raw::{c_char, c_double, c_int, c_long, c_uint, c_void};
 use std::ptr;
 
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Debug, Copy, Clone)]
 pub struct PyObject {
     #[cfg(py_sys_config = "Py_TRACE_REFS")]
     pub _ob_next: *mut PyObject,
@@ -37,17 +37,17 @@ pub struct PyVarObject {
     pub ob_size: Py_ssize_t,
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_REFCNT(ob: *mut PyObject) -> Py_ssize_t {
     (*ob).ob_refcnt
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_TYPE(ob: *mut PyObject) -> *mut PyTypeObject {
     (*ob).ob_type
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_SIZE(ob: *mut PyObject) -> Py_ssize_t {
     (*(ob as *mut PyVarObject)).ob_size
 }
@@ -564,7 +564,7 @@ extern "C" {
     pub fn PyType_IsSubtype(a: *mut PyTypeObject, b: *mut PyTypeObject) -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyObject_TypeCheck(ob: *mut PyObject, tp: *mut PyTypeObject) -> c_int {
     (Py_TYPE(ob) == tp || PyType_IsSubtype(Py_TYPE(ob), tp) != 0) as c_int
 }
@@ -576,12 +576,12 @@ extern "C" {
     pub static mut PySuper_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == (&mut PyType_Type as *mut _)) as c_int
 }
@@ -611,7 +611,7 @@ extern "C" {
     pub fn PyObject_Str(o: *mut PyObject) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyObject_Bytes(o: *mut PyObject) -> *mut PyObject {
     PyObject_Str(o)
 }
@@ -755,18 +755,18 @@ pub const Py_TPFLAGS_DEFAULT: c_long = (Py_TPFLAGS_HAVE_GETCHARBUFFER
     | Py_TPFLAGS_HAVE_INDEX
     | 0);
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_HasFeature(t: *mut PyTypeObject, f: c_long) -> c_int {
     (((*t).tp_flags & f) != 0) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_FastSubclass(t: *mut PyTypeObject, f: c_long) -> c_int {
     PyType_HasFeature(t, f)
 }
 
 // Reference counting macros.
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_INCREF(op: *mut PyObject) {
     if cfg!(py_sys_config = "Py_REF_DEBUG") {
         Py_IncRef(op)
@@ -775,7 +775,7 @@ pub unsafe fn Py_INCREF(op: *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_DECREF(op: *mut PyObject) {
     if cfg!(py_sys_config = "Py_REF_DEBUG") || cfg!(py_sys_config = "COUNT_ALLOCS") {
         Py_DecRef(op)
@@ -787,7 +787,7 @@ pub unsafe fn Py_DECREF(op: *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_CLEAR(op: &mut *mut PyObject) {
     let tmp = *op;
     if !tmp.is_null() {
@@ -796,14 +796,14 @@ pub unsafe fn Py_CLEAR(op: &mut *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_XINCREF(op: *mut PyObject) {
     if !op.is_null() {
         Py_INCREF(op)
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_XDECREF(op: *mut PyObject) {
     if !op.is_null() {
         Py_DECREF(op)
@@ -819,12 +819,12 @@ extern "C" {
     static mut _Py_NotImplementedStruct: PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_None() -> *mut PyObject {
     &mut _Py_NoneStruct
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_NotImplemented() -> *mut PyObject {
     &mut _Py_NotImplementedStruct
 }
@@ -855,7 +855,7 @@ extern "C" {
 
 pub const PyTrash_UNWIND_LEVEL: c_int = 50;
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_TRASHCAN<F: FnOnce() -> ()>(op: *mut PyObject, body: F) {
     let tstate = ffi2::pystate::PyThreadState_GET();
     if tstate.is_null() || (*tstate).trash_delete_nesting < PyTrash_UNWIND_LEVEL {
diff --git a/src/ffi2/objimpl.rs b/src/ffi2/objimpl.rs
index e9342989551..ff98af60981 100644
--- a/src/ffi2/objimpl.rs
+++ b/src/ffi2/objimpl.rs
@@ -30,14 +30,14 @@ extern "C" {
 }
 
 /// Test if a type has a GC head
-#[inline(always)]
+#[inline]
 #[allow(unused_parens)]
 pub unsafe fn PyType_IS_GC(t: *mut PyTypeObject) -> c_int {
     PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
 }
 
 /// Test if an object has a GC head
-#[inline(always)]
+#[inline]
 pub unsafe fn PyObject_IS_GC(o: *mut PyObject) -> c_int {
     (PyType_IS_GC(Py_TYPE(o)) != 0 && match (*Py_TYPE(o)).tp_is_gc {
         Some(tp_is_gc) => tp_is_gc(o) != 0,
@@ -46,13 +46,13 @@ pub unsafe fn PyObject_IS_GC(o: *mut PyObject) -> c_int {
 }
 
 /* Test if a type supports weak references */
-#[inline(always)]
+#[inline]
 #[allow(unused_parens)]
 pub unsafe fn PyType_SUPPORTS_WEAKREFS(t: *mut PyTypeObject) -> c_int {
     (PyType_HasFeature((t), Py_TPFLAGS_HAVE_WEAKREFS) != 0 && ((*t).tp_weaklistoffset > 0)) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyObject_GET_WEAKREFS_LISTPTR(o: *mut PyObject) -> *mut *mut PyObject {
     let weaklistoffset = (*Py_TYPE(o)).tp_weaklistoffset as isize;
     (o as *mut c_char).offset(weaklistoffset) as *mut *mut PyObject
diff --git a/src/ffi2/pystate.rs b/src/ffi2/pystate.rs
index eb2d5320d37..f17807b8dcc 100644
--- a/src/ffi2/pystate.rs
+++ b/src/ffi2/pystate.rs
@@ -92,13 +92,13 @@ extern "C" {
 }
 
 #[cfg(py_sys_config = "Py_DEBUG")]
-#[inline(always)]
+#[inline]
 pub unsafe fn PyThreadState_GET() -> *mut PyThreadState {
     PyThreadState_Get()
 }
 
 #[cfg(not(py_sys_config = "Py_DEBUG"))]
-#[inline(always)]
+#[inline]
 pub unsafe fn PyThreadState_GET() -> *mut PyThreadState {
     _PyThreadState_Current
 }
diff --git a/src/ffi2/rangeobject.rs b/src/ffi2/rangeobject.rs
index 4674aac8435..7153a802530 100644
--- a/src/ffi2/rangeobject.rs
+++ b/src/ffi2/rangeobject.rs
@@ -6,7 +6,7 @@ extern "C" {
     pub static mut PyRange_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyRange_Check(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyRange_Type;
     (Py_TYPE(op) == u) as c_int
diff --git a/src/ffi2/sliceobject.rs b/src/ffi2/sliceobject.rs
index 8fa6c2647d5..c3594da2f7d 100644
--- a/src/ffi2/sliceobject.rs
+++ b/src/ffi2/sliceobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     static mut _Py_EllipsisObject: PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_Ellipsis() -> *mut PyObject {
     &mut _Py_EllipsisObject
 }
@@ -32,7 +32,7 @@ extern "C" {
     pub static mut PyEllipsis_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PySlice_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PySlice_Type) as c_int
 }
diff --git a/src/ffi2/stringobject.rs b/src/ffi2/stringobject.rs
index 80fc742d92e..ca69720f322 100644
--- a/src/ffi2/stringobject.rs
+++ b/src/ffi2/stringobject.rs
@@ -23,12 +23,12 @@ extern "C" {
     pub static mut PyString_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyString_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_STRING_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBaseString_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(
         Py_TYPE(op),
@@ -36,18 +36,18 @@ pub unsafe fn PyBaseString_Check(op: *mut PyObject) -> c_int {
     )
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyString_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyString_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyString_GET_SIZE(op: *mut PyObject) -> Py_ssize_t {
     (*(op as *mut PyStringObject)).ob_size
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyString_AS_STRING(op: *mut PyObject) -> *mut c_char {
     (*(op as *mut PyStringObject)).ob_sval.as_mut_ptr()
 }
diff --git a/src/ffi2/traceback.rs b/src/ffi2/traceback.rs
index 346e5771964..2f98da2b635 100644
--- a/src/ffi2/traceback.rs
+++ b/src/ffi2/traceback.rs
@@ -26,7 +26,7 @@ extern "C" {
     pub static mut PyTraceBack_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTraceBack_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyTraceBack_Type) as c_int
 }
diff --git a/src/ffi2/tupleobject.rs b/src/ffi2/tupleobject.rs
index eed43b313d6..5b8eff7e26e 100644
--- a/src/ffi2/tupleobject.rs
+++ b/src/ffi2/tupleobject.rs
@@ -20,19 +20,19 @@ extern "C" {
     pub static mut PyTuple_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TUPLE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyTuple_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
 // Macro, trading safety for speed
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObject {
     *(*(op as *mut PyTupleObject))
         .ob_item
@@ -40,13 +40,13 @@ pub unsafe fn PyTuple_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObjec
         .offset(i as isize)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_GET_SIZE(op: *mut PyObject) -> Py_ssize_t {
     Py_SIZE(op)
 }
 
 /// Macro, *only* to be used to fill in brand new tuples
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_SET_ITEM(op: *mut PyObject, i: Py_ssize_t, v: *mut PyObject) {
     *(*(op as *mut PyTupleObject))
         .ob_item
diff --git a/src/ffi2/unicodeobject.rs b/src/ffi2/unicodeobject.rs
index 0bb57d2a822..bbd7add1972 100644
--- a/src/ffi2/unicodeobject.rs
+++ b/src/ffi2/unicodeobject.rs
@@ -35,33 +35,33 @@ extern "C" {
     pub static mut PyUnicode_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_UNICODE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_CheckExact(op: *mut PyObject) -> c_int {
     let u: *mut PyTypeObject = &mut PyUnicode_Type;
     (Py_TYPE(op) == u) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_GET_SIZE(o: *mut PyObject) -> Py_ssize_t {
     (*(o as *mut PyUnicodeObject)).length
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_GET_DATA_SIZE(o: *mut PyObject) -> Py_ssize_t {
     (*(o as *mut PyUnicodeObject)).length * Py_UNICODE_SIZE
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_AS_UNICODE(o: *mut PyObject) -> *mut Py_UNICODE {
     (*(o as *mut PyUnicodeObject)).data
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_AS_DATA(o: *mut PyObject) -> *const c_char {
     (*(o as *mut PyUnicodeObject)).data as *const c_char
 }
@@ -642,31 +642,31 @@ extern "C" {
     fn _PyUnicodeUCS2_IsAlpha(ch: Py_UNICODE) -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(py_sys_config = "Py_UNICODE_SIZE_4")]
 pub unsafe fn PyUnicode_FromStringAndSize(u: *const c_char, size: Py_ssize_t) -> *mut PyObject {
     PyUnicodeUCS4_FromStringAndSize(u, size)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(py_sys_config = "Py_UNICODE_SIZE_4"))]
 pub unsafe fn PyUnicode_FromStringAndSize(u: *const c_char, size: Py_ssize_t) -> *mut PyObject {
     PyUnicodeUCS2_FromStringAndSize(u, size)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(py_sys_config = "Py_UNICODE_SIZE_4")]
 pub unsafe fn PyUnicode_AsUTF8String(u: *mut PyObject) -> *mut PyObject {
     PyUnicodeUCS4_AsUTF8String(u)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(py_sys_config = "Py_UNICODE_SIZE_4"))]
 pub unsafe fn PyUnicode_AsUTF8String(u: *mut PyObject) -> *mut PyObject {
     PyUnicodeUCS2_AsUTF8String(u)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(py_sys_config = "Py_UNICODE_SIZE_4")]
 pub unsafe fn PyUnicode_FromEncodedObject(
     obj: *mut PyObject,
@@ -676,7 +676,7 @@ pub unsafe fn PyUnicode_FromEncodedObject(
     PyUnicodeUCS4_FromEncodedObject(obj, encoding, errors)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(py_sys_config = "Py_UNICODE_SIZE_4"))]
 pub unsafe fn PyUnicode_FromEncodedObject(
     obj: *mut PyObject,
diff --git a/src/ffi2/weakrefobject.rs b/src/ffi2/weakrefobject.rs
index abf00b61e9f..a1bd3e3c2e7 100644
--- a/src/ffi2/weakrefobject.rs
+++ b/src/ffi2/weakrefobject.rs
@@ -25,23 +25,23 @@ extern "C" {
     static mut _PyWeakref_CallableProxyType: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckRef(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut _PyWeakref_RefType)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckRefExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut _PyWeakref_RefType) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckProxy(op: *mut PyObject) -> c_int {
     ((Py_TYPE(op) == &mut _PyWeakref_ProxyType)
         || (Py_TYPE(op) == &mut _PyWeakref_CallableProxyType)) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_Check(op: *mut PyObject) -> c_int {
     (PyWeakref_CheckRef(op) != 0 || PyWeakref_CheckProxy(op) != 0) as c_int
 }
@@ -56,7 +56,7 @@ extern "C" {
     pub fn _PyWeakref_ClearRef(slf: *mut PyWeakReference);
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_GET_OBJECT(_ref: *mut PyObject) -> *mut PyObject {
     let obj = (*(_ref as *mut PyWeakReference)).wr_object;
     if Py_REFCNT(obj) > 0 {
diff --git a/src/ffi3/boolobject.rs b/src/ffi3/boolobject.rs
index 6949067cac3..0c669b2f864 100644
--- a/src/ffi3/boolobject.rs
+++ b/src/ffi3/boolobject.rs
@@ -10,17 +10,17 @@ extern "C" {
     pub fn PyBool_FromLong(arg1: c_long) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBool_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyBool_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_False() -> *mut PyObject {
     &mut _Py_FalseStruct as *mut PyLongObject as *mut PyObject
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_True() -> *mut PyObject {
     &mut _Py_TrueStruct as *mut PyLongObject as *mut PyObject
 }
diff --git a/src/ffi3/bytearrayobject.rs b/src/ffi3/bytearrayobject.rs
index 40799b408fe..1e5455286d6 100644
--- a/src/ffi3/bytearrayobject.rs
+++ b/src/ffi3/bytearrayobject.rs
@@ -8,12 +8,12 @@ extern "C" {
     pub static mut PyByteArrayIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyByteArray_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyByteArray_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyByteArray_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyByteArray_Type) as c_int
 }
diff --git a/src/ffi3/bytesobject.rs b/src/ffi3/bytesobject.rs
index ca7569d0ebf..4d1469e103a 100644
--- a/src/ffi3/bytesobject.rs
+++ b/src/ffi3/bytesobject.rs
@@ -8,12 +8,12 @@ extern "C" {
     pub static mut PyBytesIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBytes_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_BYTES_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyBytes_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyBytes_Type) as c_int
 }
diff --git a/src/ffi3/complexobject.rs b/src/ffi3/complexobject.rs
index b003e666f53..8b3ff0f5d5d 100644
--- a/src/ffi3/complexobject.rs
+++ b/src/ffi3/complexobject.rs
@@ -6,12 +6,12 @@ extern "C" {
     pub static mut PyComplex_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyComplex_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyComplex_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyComplex_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyComplex_Type) as c_int
 }
diff --git a/src/ffi3/dictobject.rs b/src/ffi3/dictobject.rs
index 20d58d1a4eb..dc4c16d8174 100644
--- a/src/ffi3/dictobject.rs
+++ b/src/ffi3/dictobject.rs
@@ -13,32 +13,32 @@ extern "C" {
     pub static mut PyDictValues_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDict_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_DICT_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDict_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyDict_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDictKeys_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyDictKeys_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDictItems_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyDictItems_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDictValues_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyDictValues_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyDictViewSet_Check(op: *mut PyObject) -> c_int {
     (PyDictKeys_Check(op) != 0 || PyDictItems_Check(op) != 0) as c_int
 }
diff --git a/src/ffi3/floatobject.rs b/src/ffi3/floatobject.rs
index 6c3bdb46122..f1b5439e664 100644
--- a/src/ffi3/floatobject.rs
+++ b/src/ffi3/floatobject.rs
@@ -6,12 +6,12 @@ extern "C" {
     pub static mut PyFloat_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFloat_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyFloat_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyFloat_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyFloat_Type) as c_int
 }
diff --git a/src/ffi3/genobject.rs b/src/ffi3/genobject.rs
index e1dad5aef44..ff22fea0d3e 100644
--- a/src/ffi3/genobject.rs
+++ b/src/ffi3/genobject.rs
@@ -23,12 +23,12 @@ extern "C" {
     pub static mut PyGen_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyGen_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyGen_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyGen_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyGen_Type) as c_int
 }
@@ -44,7 +44,7 @@ extern "C" {
     pub static mut PyCoro_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCoro_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyCoro_Type)
 }
@@ -54,7 +54,7 @@ extern "C" {
     pub static mut _PyCoroWrapper_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCoroWrapper_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut _PyCoroWrapper_Type)
 }
@@ -66,13 +66,13 @@ extern "C" {
 }
 
 #[cfg(Py_3_6)]
-#[inline(always)]
+#[inline]
 pub unsafe fn PyAsyncGen_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyAsyncGen_Type)
 }
 
 #[cfg(not(Py_3_6))]
-#[inline(always)]
+#[inline]
 pub unsafe fn PyAsyncGen_Check(_op: *mut PyObject) -> c_int {
     0
 }
diff --git a/src/ffi3/iterobject.rs b/src/ffi3/iterobject.rs
index df110ffe4ab..30bd9038912 100644
--- a/src/ffi3/iterobject.rs
+++ b/src/ffi3/iterobject.rs
@@ -10,12 +10,12 @@ extern "C" {
     pub fn PyCallIter_New(arg1: *mut PyObject, arg2: *mut PyObject) -> *mut PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PySeqIter_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PySeqIter_Type) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCallIter_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCallIter_Type) as c_int
 }
diff --git a/src/ffi3/listobject.rs b/src/ffi3/listobject.rs
index fa526b8d018..63c8efe2893 100644
--- a/src/ffi3/listobject.rs
+++ b/src/ffi3/listobject.rs
@@ -9,12 +9,12 @@ extern "C" {
     pub static mut PyListRevIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_LIST_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyList_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyList_Type) as c_int
 }
diff --git a/src/ffi3/longobject.rs b/src/ffi3/longobject.rs
index e4e7cb64b0b..49aebc559ae 100644
--- a/src/ffi3/longobject.rs
+++ b/src/ffi3/longobject.rs
@@ -12,12 +12,12 @@ extern "C" {
     pub static mut PyLong_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyLong_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_LONG_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyLong_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyLong_Type) as c_int
 }
diff --git a/src/ffi3/memoryobject.rs b/src/ffi3/memoryobject.rs
index 6b839acfa5c..90a7ccece44 100644
--- a/src/ffi3/memoryobject.rs
+++ b/src/ffi3/memoryobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     pub static mut PyMemoryView_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyMemoryView_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyMemoryView_Type) as c_int
 }
diff --git a/src/ffi3/methodobject.rs b/src/ffi3/methodobject.rs
index 33c4b1185c6..b90f52329d2 100644
--- a/src/ffi3/methodobject.rs
+++ b/src/ffi3/methodobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     pub static mut PyCFunction_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCFunction_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyCFunction_Type) as c_int
 }
@@ -63,7 +63,7 @@ impl Default for PyMethodDef {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyCFunction_New(ml: *mut PyMethodDef, slf: *mut PyObject) -> *mut PyObject {
     PyCFunction_NewEx(ml, slf, ptr::null_mut())
 }
diff --git a/src/ffi3/moduleobject.rs b/src/ffi3/moduleobject.rs
index becdb4ecda0..bd842026767 100644
--- a/src/ffi3/moduleobject.rs
+++ b/src/ffi3/moduleobject.rs
@@ -8,12 +8,12 @@ extern "C" {
     pub static mut PyModule_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyModule_Check(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut PyModule_Type)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyModule_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyModule_Type) as c_int
 }
diff --git a/src/ffi3/object.rs b/src/ffi3/object.rs
index 78f10c66685..a8c0348783c 100644
--- a/src/ffi3/object.rs
+++ b/src/ffi3/object.rs
@@ -34,7 +34,7 @@ pub struct PyVarObject {
     pub ob_size: Py_ssize_t,
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_REFCNT(ob: *mut PyObject) -> Py_ssize_t {
     if ob.is_null() {
         panic!();
@@ -42,12 +42,12 @@ pub unsafe fn Py_REFCNT(ob: *mut PyObject) -> Py_ssize_t {
     (*ob).ob_refcnt
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_TYPE(ob: *mut PyObject) -> *mut PyTypeObject {
     (*ob).ob_type
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_SIZE(ob: *mut PyObject) -> Py_ssize_t {
     (*(ob as *mut PyVarObject)).ob_size
 }
@@ -616,7 +616,7 @@ extern "C" {
     pub fn PyType_IsSubtype(a: *mut PyTypeObject, b: *mut PyTypeObject) -> c_int;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyObject_TypeCheck(ob: *mut PyObject, tp: *mut PyTypeObject) -> c_int {
     (Py_TYPE(ob) == tp || PyType_IsSubtype(Py_TYPE(ob), tp) != 0) as c_int
 }
@@ -633,12 +633,12 @@ extern "C" {
     pub fn PyType_GetFlags(arg1: *mut PyTypeObject) -> c_ulong;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyType_Type) as c_int
 }
@@ -753,19 +753,19 @@ pub const Py_TPFLAGS_DEFAULT: c_ulong =
 
 pub const Py_TPFLAGS_HAVE_FINALIZE: c_ulong = 1;
 
-#[inline(always)]
+#[inline]
 #[cfg(Py_LIMITED_API)]
 pub unsafe fn PyType_HasFeature(t: *mut PyTypeObject, f: c_ulong) -> c_int {
     ((PyType_GetFlags(t) & f) != 0) as c_int
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyType_HasFeature(t: *mut PyTypeObject, f: c_ulong) -> c_int {
     (((*t).tp_flags & f) != 0) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyType_FastSubclass(t: *mut PyTypeObject, f: c_ulong) -> c_int {
     PyType_HasFeature(t, f)
 }
@@ -776,7 +776,7 @@ extern "C" {
 }
 
 // Reference counting macros.
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_INCREF(op: *mut PyObject) {
     if cfg!(py_sys_config = "Py_REF_DEBUG") {
         Py_IncRef(op)
@@ -785,7 +785,7 @@ pub unsafe fn Py_INCREF(op: *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_DECREF(op: *mut PyObject) {
     if cfg!(py_sys_config = "Py_REF_DEBUG") {
         Py_DecRef(op)
@@ -797,7 +797,7 @@ pub unsafe fn Py_DECREF(op: *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_CLEAR(op: &mut *mut PyObject) {
     let tmp = *op;
     if !tmp.is_null() {
@@ -806,14 +806,14 @@ pub unsafe fn Py_CLEAR(op: &mut *mut PyObject) {
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_XINCREF(op: *mut PyObject) {
     if !op.is_null() {
         Py_INCREF(op)
     }
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_XDECREF(op: *mut PyObject) {
     if !op.is_null() {
         Py_DECREF(op)
@@ -829,12 +829,12 @@ extern "C" {
     static mut _Py_NotImplementedStruct: PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_None() -> *mut PyObject {
     &mut _Py_NoneStruct
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_NotImplemented() -> *mut PyObject {
     &mut _Py_NotImplementedStruct
 }
diff --git a/src/ffi3/objimpl.rs b/src/ffi3/objimpl.rs
index 2b50f36ec31..ba22cc5790f 100644
--- a/src/ffi3/objimpl.rs
+++ b/src/ffi3/objimpl.rs
@@ -48,14 +48,14 @@ extern "C" {
 }
 
 /// Test if a type has a GC head
-#[inline(always)]
+#[inline]
 #[allow(unused_parens)]
 pub unsafe fn PyType_IS_GC(t: *mut PyTypeObject) -> c_int {
     PyType_HasFeature(t, Py_TPFLAGS_HAVE_GC)
 }
 
 /// Test if an object has a GC head
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyObject_IS_GC(o: *mut PyObject) -> c_int {
     (PyType_IS_GC(Py_TYPE(o)) != 0 && match (*Py_TYPE(o)).tp_is_gc {
@@ -80,13 +80,13 @@ extern "C" {
 }
 
 /// Test if a type supports weak references
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyType_SUPPORTS_WEAKREFS(t: *mut PyTypeObject) -> c_int {
     ((*t).tp_weaklistoffset > 0) as c_int
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyObject_GET_WEAKREFS_LISTPTR(o: *mut PyObject) -> *mut *mut PyObject {
     let weaklistoffset = (*Py_TYPE(o)).tp_weaklistoffset as isize;
diff --git a/src/ffi3/pystate.rs b/src/ffi3/pystate.rs
index c33227280bb..83357640134 100644
--- a/src/ffi3/pystate.rs
+++ b/src/ffi3/pystate.rs
@@ -58,7 +58,7 @@ extern "C" {
     pub fn PyGILState_GetThisThreadState() -> *mut PyThreadState;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyThreadState_GET() -> *mut PyThreadState {
     PyThreadState_Get()
 }
diff --git a/src/ffi3/rangeobject.rs b/src/ffi3/rangeobject.rs
index 93388240150..bdd8e3396a9 100644
--- a/src/ffi3/rangeobject.rs
+++ b/src/ffi3/rangeobject.rs
@@ -8,7 +8,7 @@ extern "C" {
     pub static mut PyLongRangeIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyRange_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyRange_Type) as c_int
 }
diff --git a/src/ffi3/sliceobject.rs b/src/ffi3/sliceobject.rs
index cda1b1be1e6..2a973c0f4f0 100644
--- a/src/ffi3/sliceobject.rs
+++ b/src/ffi3/sliceobject.rs
@@ -7,7 +7,7 @@ extern "C" {
     static mut _Py_EllipsisObject: PyObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn Py_Ellipsis() -> *mut PyObject {
     &mut _Py_EllipsisObject
 }
@@ -18,7 +18,7 @@ extern "C" {
     pub static mut PyEllipsis_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PySlice_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PySlice_Type) as c_int
 }
diff --git a/src/ffi3/traceback.rs b/src/ffi3/traceback.rs
index 211fe53aa3a..096e9b1c8be 100644
--- a/src/ffi3/traceback.rs
+++ b/src/ffi3/traceback.rs
@@ -8,7 +8,7 @@ extern "C" {
     pub static mut PyTraceBack_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTraceBack_Check(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyTraceBack_Type) as c_int
 }
diff --git a/src/ffi3/tupleobject.rs b/src/ffi3/tupleobject.rs
index 4751f53de0a..994f70e552e 100644
--- a/src/ffi3/tupleobject.rs
+++ b/src/ffi3/tupleobject.rs
@@ -15,12 +15,12 @@ extern "C" {
     pub static mut PyTupleIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TUPLE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyTuple_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyTuple_Type) as c_int
 }
@@ -41,7 +41,7 @@ extern "C" {
 }
 
 // Macro, trading safety for speed
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyTuple_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObject {
     *(*(op as *mut PyTupleObject))
@@ -50,14 +50,14 @@ pub unsafe fn PyTuple_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObjec
         .offset(i as isize)
 }
 
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyTuple_GET_SIZE(op: *mut PyObject) -> Py_ssize_t {
     Py_SIZE(op)
 }
 
 /// Macro, *only* to be used to fill in brand new tuples
-#[inline(always)]
+#[inline]
 #[cfg(not(Py_LIMITED_API))]
 pub unsafe fn PyTuple_SET_ITEM(op: *mut PyObject, i: Py_ssize_t, v: *mut PyObject) {
     *(*(op as *mut PyTupleObject))
diff --git a/src/ffi3/unicodeobject.rs b/src/ffi3/unicodeobject.rs
index a227eae10c1..04893b298ba 100644
--- a/src/ffi3/unicodeobject.rs
+++ b/src/ffi3/unicodeobject.rs
@@ -16,12 +16,12 @@ extern "C" {
     pub static mut PyUnicodeIter_Type: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_Check(op: *mut PyObject) -> c_int {
     PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_UNICODE_SUBCLASS)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyUnicode_CheckExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut PyUnicode_Type) as c_int
 }
diff --git a/src/ffi3/weakrefobject.rs b/src/ffi3/weakrefobject.rs
index 07198d6dd6d..554bc9302cf 100644
--- a/src/ffi3/weakrefobject.rs
+++ b/src/ffi3/weakrefobject.rs
@@ -10,23 +10,23 @@ extern "C" {
     static mut _PyWeakref_CallableProxyType: PyTypeObject;
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckRef(op: *mut PyObject) -> c_int {
     PyObject_TypeCheck(op, &mut _PyWeakref_RefType)
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckRefExact(op: *mut PyObject) -> c_int {
     (Py_TYPE(op) == &mut _PyWeakref_RefType) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_CheckProxy(op: *mut PyObject) -> c_int {
     ((Py_TYPE(op) == &mut _PyWeakref_ProxyType)
         || (Py_TYPE(op) == &mut _PyWeakref_CallableProxyType)) as c_int
 }
 
-#[inline(always)]
+#[inline]
 pub unsafe fn PyWeakref_Check(op: *mut PyObject) -> c_int {
     (PyWeakref_CheckRef(op) != 0 || PyWeakref_CheckProxy(op) != 0) as c_int
 }
diff --git a/src/instance.rs b/src/instance.rs
index b46458ecdaa..17d27c6a2cc 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -21,7 +21,7 @@ impl PyToken {
         PyToken(PhantomData)
     }
 
-    #[inline(always)]
+    #[inline]
 
     pub fn py(&self) -> Python {
         unsafe { Python::assume_gil_acquired() }
diff --git a/src/lib.rs b/src/lib.rs
index 0107453650f..8835e2e72b3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -129,21 +129,15 @@ extern crate spin;
 #[doc(hidden)]
 pub extern crate mashup;
 
+/// Rust FFI declarations for Python
+pub mod ffi;
+
 #[cfg(not(Py_3))]
 mod ffi2;
 
 #[cfg(Py_3)]
 mod ffi3;
 
-/// Rust FFI declarations for Python
-pub mod ffi {
-    #[cfg(not(Py_3))]
-    pub use ffi2::*;
-
-    #[cfg(Py_3)]
-    pub use ffi3::*;
-}
-
 pub use conversion::{
     FromPyObject, IntoPyObject, IntoPyTuple, PyTryFrom, PyTryInto, ReturnTypeIntoPyResult,
     ToBorrowedObject, ToPyObject,
diff --git a/src/objects/datetime.rs b/src/objects/datetime.rs
new file mode 100644
index 00000000000..630fe42ca0e
--- /dev/null
+++ b/src/objects/datetime.rs
@@ -0,0 +1,300 @@
+use err::PyResult;
+use ffi;
+use ffi::PyDateTimeAPI;
+use ffi::{PyDateTime_Check, PyDateTime_DateTimeType};
+use ffi::{
+    PyDateTime_DATE_GET_HOUR, PyDateTime_DATE_GET_MICROSECOND, PyDateTime_DATE_GET_MINUTE,
+    PyDateTime_DATE_GET_SECOND,
+};
+use ffi::{
+    PyDateTime_DELTA_GET_DAYS, PyDateTime_DELTA_GET_MICROSECONDS, PyDateTime_DELTA_GET_SECONDS,
+};
+use ffi::{PyDateTime_DateType, PyDate_Check};
+use ffi::{PyDateTime_DeltaType, PyDelta_Check};
+use ffi::{PyDateTime_GET_DAY, PyDateTime_GET_MONTH, PyDateTime_GET_YEAR};
+use ffi::{
+    PyDateTime_TIME_GET_HOUR, PyDateTime_TIME_GET_MICROSECOND, PyDateTime_TIME_GET_MINUTE,
+    PyDateTime_TIME_GET_SECOND,
+};
+use ffi::{PyDateTime_TZInfoType, PyTZInfo_Check};
+use ffi::{PyDateTime_TimeType, PyTime_Check};
+use object::PyObject;
+use std::os::raw::c_int;
+
+#[cfg(Py_3_6)]
+use ffi::{PyDateTime_DATE_GET_FOLD, PyDateTime_TIME_GET_FOLD};
+
+use instance::Py;
+use python::{Python, ToPyPointer};
+
+// Traits
+pub trait PyDateAccess {
+    fn get_year(&self) -> i32;
+    fn get_month(&self) -> u8;
+    fn get_day(&self) -> u8;
+}
+
+pub trait PyDeltaAccess {
+    fn get_days(&self) -> i32;
+    fn get_seconds(&self) -> i32;
+    fn get_microseconds(&self) -> i32;
+}
+
+pub trait PyTimeAccess {
+    fn get_hour(&self) -> u8;
+    fn get_minute(&self) -> u8;
+    fn get_second(&self) -> u8;
+    fn get_microsecond(&self) -> u32;
+    #[cfg(Py_3_6)]
+    fn get_fold(&self) -> u8;
+}
+
+// datetime.date bindings
+pub struct PyDate(PyObject);
+pyobject_native_type!(PyDate, PyDateTime_DateType, PyDate_Check);
+
+impl PyDate {
+    pub fn new(py: Python, year: i32, month: u8, day: u8) -> PyResult<Py<PyDate>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.Date_FromDate)(
+                year as c_int,
+                month as c_int,
+                day as c_int,
+                PyDateTimeAPI.DateType,
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+
+    pub fn from_timestamp(py: Python, args: &PyObject) -> PyResult<Py<PyDate>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.Date_FromTimestamp)(PyDateTimeAPI.DateType, args.as_ptr());
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+}
+
+impl PyDateAccess for PyDate {
+    fn get_year(&self) -> i32 {
+        unsafe { PyDateTime_GET_YEAR(self.as_ptr()) as i32 }
+    }
+
+    fn get_month(&self) -> u8 {
+        unsafe { PyDateTime_GET_MONTH(self.as_ptr()) as u8 }
+    }
+
+    fn get_day(&self) -> u8 {
+        unsafe { PyDateTime_GET_DAY(self.as_ptr()) as u8 }
+    }
+}
+
+// datetime.datetime bindings
+pub struct PyDateTime(PyObject);
+pyobject_native_type!(PyDateTime, PyDateTime_DateTimeType, PyDateTime_Check);
+
+impl PyDateTime {
+    pub fn new(
+        py: Python,
+        year: i32,
+        month: u8,
+        day: u8,
+        hour: u8,
+        minute: u8,
+        second: u8,
+        microsecond: u32,
+        tzinfo: Option<&PyObject>,
+    ) -> PyResult<Py<PyDateTime>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.DateTime_FromDateAndTime)(
+                year as c_int,
+                month as c_int,
+                day as c_int,
+                hour as c_int,
+                minute as c_int,
+                second as c_int,
+                microsecond as c_int,
+                opt_to_pyobj(py, tzinfo),
+                PyDateTimeAPI.DateTimeType,
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+
+    pub fn from_timestamp(
+        py: Python,
+        args: &PyObject,
+        kwargs: &PyObject,
+    ) -> PyResult<Py<PyDateTime>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.DateTime_FromTimestamp)(
+                PyDateTimeAPI.DateTimeType,
+                args.as_ptr(),
+                kwargs.as_ptr(),
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+}
+
+impl PyDateAccess for PyDateTime {
+    fn get_year(&self) -> i32 {
+        unsafe { PyDateTime_GET_YEAR(self.as_ptr()) as i32 }
+    }
+
+    fn get_month(&self) -> u8 {
+        unsafe { PyDateTime_GET_MONTH(self.as_ptr()) as u8 }
+    }
+
+    fn get_day(&self) -> u8 {
+        unsafe { PyDateTime_GET_DAY(self.as_ptr()) as u8 }
+    }
+}
+
+impl PyTimeAccess for PyDateTime {
+    fn get_hour(&self) -> u8 {
+        unsafe { PyDateTime_DATE_GET_HOUR(self.as_ptr()) as u8 }
+    }
+
+    fn get_minute(&self) -> u8 {
+        unsafe { PyDateTime_DATE_GET_MINUTE(self.as_ptr()) as u8 }
+    }
+
+    fn get_second(&self) -> u8 {
+        unsafe { PyDateTime_DATE_GET_SECOND(self.as_ptr()) as u8 }
+    }
+
+    fn get_microsecond(&self) -> u32 {
+        unsafe { PyDateTime_DATE_GET_MICROSECOND(self.as_ptr()) as u32 }
+    }
+
+    #[cfg(Py_3_6)]
+    fn get_fold(&self) -> u8 {
+        unsafe { PyDateTime_DATE_GET_FOLD(self.as_ptr()) as u8 }
+    }
+}
+
+// datetime.time
+pub struct PyTime(PyObject);
+pyobject_native_type!(PyTime, PyDateTime_TimeType, PyTime_Check);
+
+impl PyTime {
+    pub fn new(
+        py: Python,
+        hour: u8,
+        minute: u8,
+        second: u8,
+        microsecond: u32,
+        tzinfo: Option<&PyObject>,
+    ) -> PyResult<Py<PyTime>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.Time_FromTime)(
+                hour as c_int,
+                minute as c_int,
+                second as c_int,
+                microsecond as c_int,
+                opt_to_pyobj(py, tzinfo),
+                PyDateTimeAPI.TimeType,
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+
+    #[cfg(Py_3_6)]
+    pub fn new_with_fold(
+        py: Python,
+        hour: u8,
+        minute: u8,
+        second: u8,
+        microsecond: u32,
+        tzinfo: Option<&PyObject>,
+        fold: bool,
+    ) -> PyResult<Py<PyTime>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.Time_FromTimeAndFold)(
+                hour as c_int,
+                minute as c_int,
+                second as c_int,
+                microsecond as c_int,
+                opt_to_pyobj(py, tzinfo),
+                fold as c_int,
+                PyDateTimeAPI.TimeType,
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+}
+
+impl PyTimeAccess for PyTime {
+    fn get_hour(&self) -> u8 {
+        unsafe { PyDateTime_TIME_GET_HOUR(self.as_ptr()) as u8 }
+    }
+
+    fn get_minute(&self) -> u8 {
+        unsafe { PyDateTime_TIME_GET_MINUTE(self.as_ptr()) as u8 }
+    }
+
+    fn get_second(&self) -> u8 {
+        unsafe { PyDateTime_TIME_GET_SECOND(self.as_ptr()) as u8 }
+    }
+
+    fn get_microsecond(&self) -> u32 {
+        unsafe { PyDateTime_TIME_GET_MICROSECOND(self.as_ptr()) as u32 }
+    }
+
+    #[cfg(Py_3_6)]
+    fn get_fold(&self) -> u8 {
+        unsafe { PyDateTime_TIME_GET_FOLD(self.as_ptr()) as u8 }
+    }
+}
+
+// datetime.tzinfo bindings
+pub struct PyTzInfo(PyObject);
+pyobject_native_type!(PyTzInfo, PyDateTime_TZInfoType, PyTZInfo_Check);
+
+// datetime.timedelta bindings
+pub struct PyDelta(PyObject);
+pyobject_native_type!(PyDelta, PyDateTime_DeltaType, PyDelta_Check);
+
+impl PyDelta {
+    pub fn new(
+        py: Python,
+        days: i32,
+        seconds: i32,
+        microseconds: i32,
+        normalize: bool,
+    ) -> PyResult<Py<PyDelta>> {
+        unsafe {
+            let ptr = (PyDateTimeAPI.Delta_FromDelta)(
+                days as c_int,
+                seconds as c_int,
+                microseconds as c_int,
+                normalize as c_int,
+                PyDateTimeAPI.DeltaType,
+            );
+            Py::from_owned_ptr_or_err(py, ptr)
+        }
+    }
+}
+
+impl PyDeltaAccess for PyDelta {
+    fn get_days(&self) -> i32 {
+        unsafe { PyDateTime_DELTA_GET_DAYS(self.as_ptr()) as i32 }
+    }
+
+    fn get_seconds(&self) -> i32 {
+        unsafe { PyDateTime_DELTA_GET_SECONDS(self.as_ptr()) as i32 }
+    }
+
+    fn get_microseconds(&self) -> i32 {
+        unsafe { PyDateTime_DELTA_GET_MICROSECONDS(self.as_ptr()) as i32 }
+    }
+}
+
+// Utility function
+unsafe fn opt_to_pyobj(py: Python, opt: Option<&PyObject>) -> *mut ffi::PyObject {
+    // Convenience function for unpacking Options to either an Object or None
+    match opt {
+        Some(tzi) => tzi.as_ptr(),
+        None => py.None().as_ptr(),
+    }
+}
diff --git a/src/objects/exc.rs b/src/objects/exc.rs
index de8ddda16df..866263fd057 100644
--- a/src/objects/exc.rs
+++ b/src/objects/exc.rs
@@ -38,7 +38,7 @@ macro_rules! exc_type(
             }
         }
         impl PyTypeObject for $name {
-            #[inline(always)]
+            #[inline]
             fn init_type() {}
 
             #[inline]
diff --git a/src/objects/exc_impl.rs b/src/objects/exc_impl.rs
index 4846764ea90..c6eb50bf83d 100644
--- a/src/objects/exc_impl.rs
+++ b/src/objects/exc_impl.rs
@@ -69,7 +69,7 @@ macro_rules! import_exception {
         }
 
         impl $crate::typeob::PyTypeObject for $name {
-            #[inline(always)]
+            #[inline]
             fn init_type() {}
 
             #[inline]
diff --git a/src/objects/mod.rs b/src/objects/mod.rs
index 2a4a1a13dc6..9e644e007c1 100644
--- a/src/objects/mod.rs
+++ b/src/objects/mod.rs
@@ -5,6 +5,9 @@ mod exc_impl;
 
 pub use self::boolobject::PyBool;
 pub use self::bytearray::PyByteArray;
+pub use self::datetime::PyDeltaAccess;
+pub use self::datetime::{PyDate, PyDateTime, PyDelta, PyTime, PyTzInfo};
+pub use self::datetime::{PyDateAccess, PyTimeAccess};
 pub use self::dict::PyDict;
 pub use self::floatob::PyFloat;
 pub use self::iterator::PyIterator;
@@ -65,7 +68,7 @@ macro_rules! pyobject_native_type_named(
         }
 
         impl<$($type_param,)*> $crate::PyObjectWithToken for $name {
-            #[inline(always)]
+            #[inline]
             fn py(&self) -> $crate::Python {
                 unsafe { $crate::Python::assume_gil_acquired() }
             }
@@ -126,7 +129,7 @@ macro_rules! pyobject_native_type_convert(
         }
 
         impl<$($type_param,)*> $crate::typeob::PyTypeObject for $name {
-            #[inline(always)]
+            #[inline]
             fn init_type() {}
 
             #[inline]
@@ -185,6 +188,7 @@ pyobject_native_type_convert!(PyObjectRef, ffi::PyBaseObject_Type, ffi::PyObject
 
 mod boolobject;
 mod bytearray;
+mod datetime;
 mod dict;
 pub mod exc;
 mod floatob;
diff --git a/src/typeob.rs b/src/typeob.rs
index 88a1f1d47fd..df5fa3c49c3 100644
--- a/src/typeob.rs
+++ b/src/typeob.rs
@@ -205,7 +205,7 @@ impl IntoPyPointer for PyRawObject {
 }
 
 impl PyObjectWithToken for PyRawObject {
-    #[inline(always)]
+    #[inline]
     fn py(&self) -> Python {
         unsafe { Python::assume_gil_acquired() }
     }
diff --git a/tests/test_datetime.rs b/tests/test_datetime.rs
new file mode 100644
index 00000000000..61eb7b5f7ab
--- /dev/null
+++ b/tests/test_datetime.rs
@@ -0,0 +1,211 @@
+#![feature(concat_idents)]
+
+extern crate pyo3;
+
+use std::iter;
+
+use pyo3::ffi::*;
+use pyo3::prelude::*;
+
+fn _get_subclasses<'p>(
+    py: &'p Python,
+    py_type: &str,
+    args: &str,
+) -> PyResult<(&'p PyObjectRef, &'p PyObjectRef, &'p PyObjectRef)> {
+    // Import the class from Python and create some subclasses
+    let datetime = py.import("datetime")?;
+
+    let locals = PyDict::new(*py);
+    locals.set_item(py_type, datetime.get(py_type)?).unwrap();
+
+    let make_subclass_py = format!("class Subklass({}):\n    pass", py_type);
+
+    let make_sub_subclass_py = "class SubSubklass(Subklass):\n    pass";
+
+    py.run(&make_subclass_py, None, Some(&locals))?;
+    py.run(&make_sub_subclass_py, None, Some(&locals))?;
+
+    // Construct an instance of the base class
+    let obj = py.eval(&format!("{}({})", py_type, args), None, Some(&locals))?;
+
+    // Construct an instance of the subclass
+    let sub_obj = py.eval(&format!("Subklass({})", args), None, Some(&locals))?;
+
+    // Construct an instance of the sub-subclass
+    let sub_sub_obj = py.eval(&format!("SubSubklass({})", args), None, Some(&locals))?;
+
+    Ok((obj, sub_obj, sub_sub_obj))
+}
+
+macro_rules! assert_check_exact {
+    ($check_func:ident, $obj: expr) => {
+        unsafe {
+            assert!($check_func(($obj).as_ptr()) != 0);
+            assert!(concat_idents!($check_func, Exact)(($obj).as_ptr()) != 0);
+        }
+    };
+}
+
+macro_rules! assert_check_only {
+    ($check_func:ident, $obj: expr) => {
+        unsafe {
+            assert!($check_func(($obj).as_ptr()) != 0);
+            assert!(concat_idents!($check_func, Exact)(($obj).as_ptr()) == 0);
+        }
+    };
+}
+
+#[test]
+fn test_date_check() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let (obj, sub_obj, sub_sub_obj) = _get_subclasses(&py, "date", "2018, 1, 1").unwrap();
+
+    assert_check_exact!(PyDate_Check, obj);
+    assert_check_only!(PyDate_Check, sub_obj);
+    assert_check_only!(PyDate_Check, sub_sub_obj);
+}
+
+#[test]
+fn test_time_check() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let (obj, sub_obj, sub_sub_obj) = _get_subclasses(&py, "time", "12, 30, 15").unwrap();
+
+    assert_check_exact!(PyTime_Check, obj);
+    assert_check_only!(PyTime_Check, sub_obj);
+    assert_check_only!(PyTime_Check, sub_sub_obj);
+}
+
+#[test]
+fn test_datetime_check() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let (obj, sub_obj, sub_sub_obj) =
+        _get_subclasses(&py, "datetime", "2018, 1, 1, 13, 30, 15").unwrap();
+
+    assert_check_only!(PyDate_Check, obj);
+    assert_check_exact!(PyDateTime_Check, obj);
+    assert_check_only!(PyDateTime_Check, sub_obj);
+    assert_check_only!(PyDateTime_Check, sub_sub_obj);
+}
+
+#[test]
+fn test_delta_check() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let (obj, sub_obj, sub_sub_obj) = _get_subclasses(&py, "timedelta", "1, -3").unwrap();
+
+    assert_check_exact!(PyDelta_Check, obj);
+    assert_check_only!(PyDelta_Check, sub_obj);
+    assert_check_only!(PyDelta_Check, sub_sub_obj);
+}
+
+#[test]
+#[cfg(Py_3)]
+fn test_datetime_utc() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let datetime = py.import("datetime").map_err(|e| e.print(py)).unwrap();
+    let timezone = datetime.get("timezone").unwrap();
+    let utc = timezone.getattr("utc").unwrap().to_object(py);
+
+    let dt = PyDateTime::new(py, 2018, 1, 1, 0, 0, 0, 0, Some(&utc)).unwrap();
+
+    let locals = PyDict::new(py);
+    locals.set_item("dt", dt).unwrap();
+
+    let offset: f32 = py
+        .eval("dt.utcoffset().total_seconds()", None, Some(locals))
+        .unwrap()
+        .extract()
+        .unwrap();
+    assert_eq!(offset, 0f32);
+}
+
+static INVALID_DATES: &'static [(i32, u8, u8)] = &[
+    (-1, 1, 1),
+    (0, 1, 1),
+    (10000, 1, 1),
+    (2 << 30, 1, 1),
+    (2018, 0, 1),
+    (2018, 13, 1),
+    (2018, 1, 0),
+    (2017, 2, 29),
+    (2018, 1, 32),
+];
+
+static INVALID_TIMES: &'static [(u8, u8, u8, u32)] =
+    &[(25, 0, 0, 0), (255, 0, 0, 0), (0, 60, 0, 0), (0, 0, 61, 0)];
+
+#[cfg(Py_3_6)]
+#[test]
+fn test_pydate_out_of_bounds() {
+    // This test is an XFAIL on Python < 3.6 until bounds checking is implemented
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    for val in INVALID_DATES.into_iter() {
+        let (year, month, day) = val;
+        let dt = PyDate::new(py, *year, *month, *day);
+        let msg = format!("Should have raised an error: {:#?}", val);
+        match dt {
+            Ok(_) => assert!(false, msg),
+            Err(_) => assert!(true),
+        }
+    }
+}
+
+#[cfg(Py_3_6)]
+#[test]
+fn test_pytime_out_of_bounds() {
+    // This test is an XFAIL on Python < 3.6 until bounds checking is implemented
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    for val in INVALID_TIMES.into_iter() {
+        let (hour, minute, second, microsecond) = val;
+        let dt = PyTime::new(py, *hour, *minute, *second, *microsecond, None);
+        let msg = format!("Should have raised an error: {:#?}", val);
+        match dt {
+            Ok(_) => assert!(false, msg),
+            Err(_) => assert!(true),
+        }
+    }
+}
+
+#[cfg(Py_3_6)]
+#[test]
+fn test_pydatetime_out_of_bounds() {
+    // This test is an XFAIL on Python < 3.6 until bounds checking is implemented
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let valid_time = (0, 0, 0, 0);
+    let valid_date = (2018, 1, 1);
+
+    let invalid_dates = INVALID_DATES.into_iter().zip(iter::repeat(&valid_time));
+    let invalid_times = iter::repeat(&valid_date).zip(INVALID_TIMES.into_iter());
+
+    let vals = invalid_dates.chain(invalid_times);
+
+    for val in vals {
+        let (date, time) = val;
+        let (year, month, day) = date;
+        let (hour, minute, second, microsecond) = time;
+        let dt = PyDateTime::new(
+            py,
+            *year,
+            *month,
+            *day,
+            *hour,
+            *minute,
+            *second,
+            *microsecond,
+            None,
+        );
+        let msg = format!("Should have raised an error: {:#?}", val);
+        match dt {
+            Ok(_) => assert!(false, msg),
+            Err(_) => assert!(true),
+        }
+    }
+}