syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"ImplSource::Builtin(BuiltinImplSource::Misc,"}]}
source_snippet:                 ImplSource::Builtin(BuiltinImplSource::Misc, data)
context_before:                 let data = self.confirm_auto_impl_candidate(obligation)?;
context_after:             }