DefNodeWrapper: set __pyx_r to error_value() on error

Cython/Compiler/Nodes.py

@@ -3365,6 +3365,9 @@ class DefNodeWrapper(FuncDefNode):
             code.put_label(code.error_label)
             for cname, type in code.funcstate.all_managed_temps():
                 code.put_xdecref(cname, type)
+            err_val = self.error_value()
+            if err_val is not None:
+                code.putln("%s = %s;" % (Naming.retval_cname, err_val))
 
         # ----- Non-error return cleanup
         code.put_label(code.return_label)

tests/run/defnode_err_val.pyx

+# mode: run
+
+cdef class TestErrVal(object):
+    def __cinit__(self, TestErrVal a):
+        pass
+
+
+def test_errval():
+    """
+    >>> test_errval()
+    Traceback (most recent call last):
+    ...
+    TypeError: Argument 'a' has incorrect type (expected defnode_err_val.TestErrVal, got int)
+    """
+    TestErrVal(123)