diff --git a/changelog/4829.trivial.rst b/changelog/4829.trivial.rst
new file mode 100644
index 000000000..a1935b462
--- /dev/null
+++ b/changelog/4829.trivial.rst
@@ -0,0 +1 @@
+Some left-over internal code related to ``yield`` tests has been removed.
diff --git a/src/_pytest/debugging.py b/src/_pytest/debugging.py
index 271a590a1..6d51ec59c 100644
--- a/src/_pytest/debugging.py
+++ b/src/_pytest/debugging.py
@@ -209,17 +209,12 @@ def _test_pytest_function(pyfuncitem):
     _pdb = pytestPDB._init_pdb()
     testfunction = pyfuncitem.obj
     pyfuncitem.obj = _pdb.runcall
-    if pyfuncitem._isyieldedfunction():
-        arg_list = list(pyfuncitem._args)
-        arg_list.insert(0, testfunction)
-        pyfuncitem._args = tuple(arg_list)
-    else:
-        if "func" in pyfuncitem._fixtureinfo.argnames:
-            raise ValueError("--trace can't be used with a fixture named func!")
-        pyfuncitem.funcargs["func"] = testfunction
-        new_list = list(pyfuncitem._fixtureinfo.argnames)
-        new_list.append("func")
-        pyfuncitem._fixtureinfo.argnames = tuple(new_list)
+    if "func" in pyfuncitem._fixtureinfo.argnames:  # noqa
+        raise ValueError("--trace can't be used with a fixture named func!")
+    pyfuncitem.funcargs["func"] = testfunction
+    new_list = list(pyfuncitem._fixtureinfo.argnames)
+    new_list.append("func")
+    pyfuncitem._fixtureinfo.argnames = tuple(new_list)
 
 
 def _enter_pdb(node, excinfo, rep):
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 215015d27..e41acfecc 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -156,14 +156,9 @@ def pytest_configure(config):
 @hookimpl(trylast=True)
 def pytest_pyfunc_call(pyfuncitem):
     testfunction = pyfuncitem.obj
-    if pyfuncitem._isyieldedfunction():
-        testfunction(*pyfuncitem._args)
-    else:
-        funcargs = pyfuncitem.funcargs
-        testargs = {}
-        for arg in pyfuncitem._fixtureinfo.argnames:
-            testargs[arg] = funcargs[arg]
-        testfunction(**testargs)
+    funcargs = pyfuncitem.funcargs
+    testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
+    testfunction(**testargs)
     return True
 
 
@@ -1405,7 +1400,7 @@ class Function(FunctionMixin, nodes.Item, fixtures.FuncargnamesCompatAttr):
 
         if fixtureinfo is None:
             fixtureinfo = self.session._fixturemanager.getfixtureinfo(
-                self, self.obj, self.cls, funcargs=not self._isyieldedfunction()
+                self, self.obj, self.cls, funcargs=True
             )
         self._fixtureinfo = fixtureinfo
         self.fixturenames = fixtureinfo.names_closure
@@ -1419,16 +1414,6 @@ class Function(FunctionMixin, nodes.Item, fixtures.FuncargnamesCompatAttr):
 
     def _initrequest(self):
         self.funcargs = {}
-        if self._isyieldedfunction():
-            assert not hasattr(
-                self, "callspec"
-            ), "yielded functions (deprecated) cannot have funcargs"
-        else:
-            if hasattr(self, "callspec"):
-                callspec = self.callspec
-                assert not callspec.funcargs
-                if hasattr(callspec, "param"):
-                    self.param = callspec.param
         self._request = fixtures.FixtureRequest(self)
 
     @property
@@ -1448,9 +1433,6 @@ class Function(FunctionMixin, nodes.Item, fixtures.FuncargnamesCompatAttr):
         "(compatonly) for code expecting pytest-2.2 style request objects"
         return self
 
-    def _isyieldedfunction(self):
-        return getattr(self, "_args", None) is not None
-
     def runtest(self):
         """ execute the underlying test function. """
         self.ihook.pytest_pyfunc_call(pyfuncitem=self)