syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Prefix arguments are passed in specific designated registers
context_before:     pub fn unaligned_size<C: HasDataLayout>(&self, _cx: &C) -> Size {
context_after:         let prefix_size = if let Some(offset_from_start) = self.rest_offset {