syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"AddGoal(GoalSource,"}]}
source_snippet:     AddGoal(GoalSource, CanonicalState<I, Goal<I, I::Predicate>>),
context_before:     /// the next time `EvalCtxt::try_evaluate_added_goals` is called.
context_after:     /// A call to `probe` while proving the current goal. This is