syntax_data: {"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // Store this set of additional projections (fields and derefs).
context_before:         |(parent_field_idx, parent_capture), (child_field_idx, child_capture)| {
context_after:             // We need to re-apply them later.