syntax_data: {"ast_node_type":"variable","tokens":[{"end":90,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let predicate = self.infcx.resolve_vars_if_possible(obligation.predicate);
context_before:             Err(()) => {
context_after:                 bug!("impl {impl_def_id:?} was matchable against {predicate:?} but now is not")