syntax_data: {"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"source_data.principal().unwrap().with_self_ty(tcx,"}]}
source_snippet:         source_data.principal().unwrap().with_self_ty(tcx, source),
context_before:     let source_principal = tcx.instantiate_bound_regions_with_erased(
context_after:     );