Added check to make sure the variable is of the user specified size after…

theano/tensor/basic.py

@@ -167,7 +167,12 @@ def as_tensor_variable(x, name=None, ndim=None):
                 # strip off leading broadcastable dimensions
                 first_non_broadcastable = [idx for idx in range(x.ndim)
                                            if x.broadcastable[idx] == False][0]
-                return x.dimshuffle(range(x.ndim)[first_non_broadcastable:])
+                x = x.dimshuffle(range(x.ndim)[first_non_broadcastable:])
+                if x.ndim > ndim:
+                    raise ValueError(
+                        'TensorType could not be cast to have %i dimensions' % ndim, x.type
+                    )
+                return x
             elif (x.type.ndim < ndim):
                 return shape_padleft(x, n_ones=(ndim - x.type.ndim))
             else:

theano/tensor/tests/test_basic.py

@@ -1920,10 +1920,17 @@ Allocb4GradTester = makeBroadcastTester(
 
 
 def test_as_tensor_variable():
-    x = tensor.TensorType(config.floatX, (True, False))()
+    x = tensor.TensorType(config.floatX, (True, False))('x')
     x = as_tensor_variable(x, ndim=1)
     assert(x.ndim == 1)
 
+    x = tensor.matrix('x', dtype=config.floatX)
+    try:
+        x = as_tensor_variable(x, ndim=1)
+        assert(False)  # The call above should have failed
+    except ValueError:
+        pass
+
 
 class TestAlloc(unittest.TestCase):
     dtype = config.floatX