syntax_data: {"ast_node_type":"other","tokens":[{"end":64,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //!   except it always returns a fresh place, even for constants
context_before: //! - `as_temp` -- evaluates into a temporary; this is similar to `as_operand`
context_after: //! - `as_rvalue` -- yields an `Rvalue`, suitable for use in an assignment;