syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // generics do as the trait always has a self ty param. We need to offset.
context_before:         // The args don't contain the self ty (as it has been erased) but the corresp.
context_after:         let args = &self.args[p.tcx().generics_of(self.def_id).parent_count - 1..];