Why is the mask in BertSelfOutput not passed through the MaskedLayerNorm?

[andrewboldi]

In the following code in deberta/bert.py, why are we not passing in the mask to the MaskedLayerNorm in line 38? If the mask is not needed, can't we directly call hidden_states = self.LayerNorm(hidden_states)?

DeBERTa/DeBERTa/deberta/bert.py

Lines 26 to 39 in 4d7fe0b

	class BertSelfOutput(nn.Module):
	def __init__(self, config):
	super().__init__()
	self.dense = nn.Linear(config.hidden_size, config.hidden_size)
	self.LayerNorm = LayerNorm(config.hidden_size, config.layer_norm_eps)
	self.dropout = StableDropout(config.hidden_dropout_prob)
	self.config = config
	def forward(self, hidden_states, input_states, mask=None):
	hidden_states = self.dense(hidden_states)
	hidden_states = self.dropout(hidden_states)
	hidden_states += input_states
	hidden_states = MaskedLayerNorm(self.LayerNorm, hidden_states)
	return hidden_states

Thank you in advance!