import paddle

paddle.enable_static()
x = paddle.static.data(name='x', shape=[-1, 1, -1], dtype='float32')
index = paddle.static.data(name='index', shape=[-1, 1, -1], dtype='bool')
a = paddle.static.data(name="a", shape=[-1, ])
# getitem for bool tensor
out = x[index]

# setitem for bool tensor
x[index] = a

x = paddle.rand((2,3,4))
index = x < 0   # all elements are False
x[index].shape 

# before this PR :  [0, 3, 4]
# After this PR: [0]

index = index[:, :, 0]  # shape of index is [2, 3]
x[index].shape 
# before this PR :  [0, 3, 4]
# After this PR: [0, 4]

# when length of index is less than x, and the later part of x.shape contains -1
x = paddle.static.data(name='x', shape=[-1, 1, -1], dtype='float32')
index = paddle.static.data(name='index', shape=[-1, 1], dtype='bool')
x[index] = a   # will raise a error