syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! needs to be treated as mapping to the same move path as `a[y]` as
context_before: //! in both domains). Indexed projections are the exception: `a[x]`
context_after: //! well as `a[13]`, etc. So we map these `x`/`y` values to `()`.