syntax_data: {"ast_node_type":"struct","tokens":[{"end":68,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! struct expression (or other expression that creates a new value)
context_before: //! `Category::of` function in the `category` module. For example, a
context_after: //! is typically easiest to write in terms of `as_rvalue` or `into`,