syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // `TrustedLen`, which in turn means that this `.collect()`
context_before:                 // IntoIterator>::IntoIter` and `std::iter::Map` both implement
context_after:                 // allocates the correct number of elements once up-front [1].