syntax_data: {"ast_node_type":"other","tokens":[{"end":70,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! which is a [GoalEvaluation]. These  trees are used by the compiler
context_before: //! During trait solving we optionally build "proof trees", the root of
context_after: //! to inspect the behavior of the trait solver and to access its internal