diff -r dc0811953034 Lib/_pyio.py
--- a/Lib/_pyio.py	Fri Mar 25 12:50:54 2016 +0100
+++ b/Lib/_pyio.py	Fri Mar 25 13:56:34 2016 +0100
@@ -375,14 +375,19 @@ class IOBase(metaclass=abc.ABCMeta):
 
     def __del__(self):
         """Destructor.  Calls close()."""
-        # The try/except block is in case this is called at program
-        # exit time, when it's possible that globals have already been
-        # deleted, and then the close() call might fail.  Since
-        # there's nothing we can do about such failures and they annoy
-        # the end users, we suppress the traceback.
+        if self.closed:
+            return
+
+        import warnings
+        warnings.warn('unclosed file %r' % (self,), ResourceWarning,
+                      stacklevel=2, source=self)
+
         try:
             self.close()
         except:
+            # Silencing I/O errors is bad, but printing spurious tracebacks is
+            # equally as bad, and potentially more frequent (because of
+            # shutdown issues).
             pass
 
     ### Inquiries ###
@@ -1510,13 +1515,6 @@ class FileIO(RawIOBase):
             raise
         self._fd = fd
 
-    def __del__(self):
-        if self._fd >= 0 and self._closefd and not self.closed:
-            import warnings
-            warnings.warn('unclosed file %r' % (self,), ResourceWarning,
-                          stacklevel=2, source=self)
-            self.close()
-
     def __getstate__(self):
         raise TypeError("cannot serialize '%s' object", self.__class__.__name__)
 
diff -r dc0811953034 Modules/_io/bufferedio.c
--- a/Modules/_io/bufferedio.c	Fri Mar 25 12:50:54 2016 +0100
+++ b/Modules/_io/bufferedio.c	Fri Mar 25 13:56:34 2016 +0100
@@ -32,7 +32,6 @@ class io_ssize_t_converter(CConverter):
 /*[python end generated code: output=da39a3ee5e6b4b0d input=d0a811d3cbfd1b33]*/
 
 _Py_IDENTIFIER(close);
-_Py_IDENTIFIER(_dealloc_warn);
 _Py_IDENTIFIER(flush);
 _Py_IDENTIFIER(isatty);
 _Py_IDENTIFIER(mode);
@@ -446,23 +445,6 @@ buffered_clear(buffered *self)
     return 0;
 }
 
-/* Because this can call arbitrary code, it shouldn't be called when
-   the refcount is 0 (that is, not directly from tp_dealloc unless
-   the refcount has been temporarily re-incremented). */
-static PyObject *
-buffered_dealloc_warn(buffered *self, PyObject *source)
-{
-    if (self->ok && self->raw) {
-        PyObject *r;
-        r = _PyObject_CallMethodId(self->raw, &PyId__dealloc_warn, "O", source);
-        if (r)
-            Py_DECREF(r);
-        else
-            PyErr_Clear();
-    }
-    Py_RETURN_NONE;
-}
-
 /*
  * _BufferedIOMixin methods
  * This is not a class, just a collection of methods that will be reused
@@ -518,13 +500,6 @@ buffered_close(buffered *self, PyObject 
         goto end;
     }
 
-    if (self->finalizing) {
-        PyObject *r = buffered_dealloc_warn(self, (PyObject *) self);
-        if (r)
-            Py_DECREF(r);
-        else
-            PyErr_Clear();
-    }
     /* flush() will most probably re-take the lock, so drop it first */
     LEAVE_BUFFERED(self)
     res = PyObject_CallMethodObjArgs((PyObject *)self, _PyIO_str_flush, NULL);
@@ -2401,7 +2376,6 @@ static PyMethodDef bufferedreader_method
     {"writable", (PyCFunction)buffered_writable, METH_NOARGS},
     {"fileno", (PyCFunction)buffered_fileno, METH_NOARGS},
     {"isatty", (PyCFunction)buffered_isatty, METH_NOARGS},
-    {"_dealloc_warn", (PyCFunction)buffered_dealloc_warn, METH_O},
     {"__getstate__", (PyCFunction)buffered_getstate, METH_NOARGS},
 
     _IO__BUFFERED_READ_METHODDEF
@@ -2493,7 +2467,6 @@ static PyMethodDef bufferedwriter_method
     {"writable", (PyCFunction)buffered_writable, METH_NOARGS},
     {"fileno", (PyCFunction)buffered_fileno, METH_NOARGS},
     {"isatty", (PyCFunction)buffered_isatty, METH_NOARGS},
-    {"_dealloc_warn", (PyCFunction)buffered_dealloc_warn, METH_O},
     {"__getstate__", (PyCFunction)buffered_getstate, METH_NOARGS},
 
     _IO_BUFFEREDWRITER_WRITE_METHODDEF
@@ -2660,7 +2633,6 @@ static PyMethodDef bufferedrandom_method
     {"writable", (PyCFunction)buffered_writable, METH_NOARGS},
     {"fileno", (PyCFunction)buffered_fileno, METH_NOARGS},
     {"isatty", (PyCFunction)buffered_isatty, METH_NOARGS},
-    {"_dealloc_warn", (PyCFunction)buffered_dealloc_warn, METH_O},
     {"__getstate__", (PyCFunction)buffered_getstate, METH_NOARGS},
 
     {"flush", (PyCFunction)buffered_flush, METH_NOARGS},
diff -r dc0811953034 Modules/_io/fileio.c
--- a/Modules/_io/fileio.c	Fri Mar 25 12:50:54 2016 +0100
+++ b/Modules/_io/fileio.c	Fri Mar 25 13:56:34 2016 +0100
@@ -83,25 +83,6 @@ int
     return ((fileio *)self)->fd < 0;
 }
 
-/* Because this can call arbitrary code, it shouldn't be called when
-   the refcount is 0 (that is, not directly from tp_dealloc unless
-   the refcount has been temporarily re-incremented). */
-static PyObject *
-fileio_dealloc_warn(fileio *self, PyObject *source)
-{
-    if (self->fd >= 0 && self->closefd) {
-        PyObject *exc, *val, *tb;
-        PyErr_Fetch(&exc, &val, &tb);
-        if (PyErr_ResourceWarning(source, 1, "unclosed file %R", source)) {
-            /* Spurious errors can appear at shutdown */
-            if (PyErr_ExceptionMatches(PyExc_Warning))
-                PyErr_WriteUnraisable((PyObject *) self);
-        }
-        PyErr_Restore(exc, val, tb);
-    }
-    Py_RETURN_NONE;
-}
-
 static PyObject *
 portable_lseek(int fd, PyObject *posobj, int whence);
 
@@ -163,13 +144,6 @@ static PyObject *
     }
     if (res == NULL)
         PyErr_Fetch(&exc, &val, &tb);
-    if (self->finalizing) {
-        PyObject *r = fileio_dealloc_warn(self, (PyObject *) self);
-        if (r)
-            Py_DECREF(r);
-        else
-            PyErr_Clear();
-    }
     rc = internal_close(self);
     if (res == NULL)
         _PyErr_ChainExceptions(exc, val, tb);
@@ -1143,7 +1117,6 @@ static PyMethodDef fileio_methods[] = {
     _IO_FILEIO_WRITABLE_METHODDEF
     _IO_FILEIO_FILENO_METHODDEF
     _IO_FILEIO_ISATTY_METHODDEF
-    {"_dealloc_warn", (PyCFunction)fileio_dealloc_warn, METH_O, NULL},
     {"__getstate__", (PyCFunction)fileio_getstate, METH_NOARGS, NULL},
     {NULL,           NULL}             /* sentinel */
 };
diff -r dc0811953034 Modules/_io/iobase.c
--- a/Modules/_io/iobase.c	Fri Mar 25 12:50:54 2016 +0100
+++ b/Modules/_io/iobase.c	Fri Mar 25 13:56:34 2016 +0100
@@ -255,6 +255,12 @@ iobase_finalize(PyObject *self)
             PyErr_Clear();
     }
     if (closed == 0) {
+        if (PyErr_ResourceWarning(self, 1, "unclosed file %R", self)) {
+            /* Spurious errors can appear at shutdown */
+            if (PyErr_ExceptionMatches(PyExc_Warning))
+                PyErr_WriteUnraisable((PyObject *) self);
+        }
+
         /* Signal close() that it was called as part of the object
            finalization process. */
         if (_PyObject_SetAttrId(self, &PyId__finalizing, Py_True))
diff -r dc0811953034 Modules/_io/textio.c
--- a/Modules/_io/textio.c	Fri Mar 25 12:50:54 2016 +0100
+++ b/Modules/_io/textio.c	Fri Mar 25 13:56:34 2016 +0100
@@ -26,7 +26,6 @@ class io_ssize_t_converter(CConverter):
 /*[python end generated code: output=da39a3ee5e6b4b0d input=d0a811d3cbfd1b33]*/
 
 _Py_IDENTIFIER(close);
-_Py_IDENTIFIER(_dealloc_warn);
 _Py_IDENTIFIER(decode);
 _Py_IDENTIFIER(fileno);
 _Py_IDENTIFIER(flush);
@@ -2650,13 +2649,6 @@ static PyObject *
     }
     else {
         PyObject *exc = NULL, *val, *tb;
-        if (self->finalizing) {
-            res = _PyObject_CallMethodId(self->buffer, &PyId__dealloc_warn, "O", self);
-            if (res)
-                Py_DECREF(res);
-            else
-                PyErr_Clear();
-        }
         res = _PyObject_CallMethodId((PyObject *)self, &PyId_flush, NULL);
         if (res == NULL)
             PyErr_Fetch(&exc, &val, &tb);