syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // same region and mutability as the receiver. This holds for
context_before:         // Reconstruct the output assuming it's a reference with the
context_after:         // `Deref(Mut)::deref(_mut)` and `Index(Mut)::index(_mut)`.