syntax_data: {"ast_node_type":"impl","tokens":[{"end":42,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // in the same impl block.
context_before:                 // supporting the case of a method defining opaque types from assoc types
context_after:                 if let Some(impl_trait_ref) = self.parent_impl_trait_ref() {