fix gh-855.

theano/tensor/sharedvar.py

@@ -59,11 +59,17 @@ class ScalarSharedVariable(_tensor_py_operators, SharedVariable):
 
 
 @shared_constructor
-def scalar_constructor(value, name=None, strict=False, allow_downcast=None):
+def scalar_constructor(value, name=None, strict=False, allow_downcast=None,
+                       borrow=False, ):
     """SharedVariable constructor for scalar values. Default: int64 or float64.
 
     :note: We implement this using 0-d tensors for now.
 
+    :note: We ignore the borrow parameter as we convert value to an
+      ndarray (this is a new object). This respect the semantic of
+      borrow, as it is an hint to Theano that we can reuse it, this
+      isn't mandatory.
+
     """
     if not isinstance(value, (numpy.number, float, int, complex)):
         raise TypeError()

theano/tensor/tests/test_sharedvar.py

@@ -617,3 +617,8 @@ test_shared_options = makeSharedTester(
     cast_value_=numpy.asarray,
     op_by_matrix_=False,
     name='test_shared_options')
+
+
+def test_scalar_shared_options():
+    # Simple test to make sure we do not loose that fonctionality.
+    theano.shared(value=0., name='lk', borrow=True)